airpak常见问题问与答(一)建模基础
Airpak原创培训学习教程-中文教程(自然通风、空调、污染物CFD流体模拟)
Airpak软件简介
1.1.2 Airpak软件特点 （1）快速建模 Airpak是基于"object"的建模方式，这些"object"包括房间、人体、块 、风扇、通风孔、墙壁、隔板、热负荷源、阻尼板(块)、排烟罩等模型 。另外，Airpak还提供了各式各样的diffuser模型，以及用于计算大气 边界层的模型。Airpak同时还提供了与CAD软件的接口，可以通过IGES 和DXF格式导入CAD软件的几何。
Airpak软件简介
1.1.2 Airpak软件特点 （5）强大的报告和可视化工具 Airpak提供了强大的数值报告，可以模拟不同空调系统送风气流组织形式下室内的温度场、湿度场、 速度场、空气龄场、污染物浓度场、PMV场 、PPD场等，以对房间的气流组织、热舒适性和室内空 气品质(IAQ)进行全面综合评价。使您更方便地理解和比较分析结果。您可以看到速度矢量、云图和 粒子流线动画等。它可以实时描绘出气流运动情况。 设计性能评估 后处理还包括产品设计性能的评估，气流、温度、湿度分布、舒适度、压力等参数。
Airpak软件简介
1.1.2 Airpak软件特点 （2）自动的网格划分功能 Airpak具有自动化的非结构化、结构化网格生成能力。支持四面体、六面体以及混合 网格，因而可以在模型上生成高质量的网格。
Airpak软件简介
1.1.2 Airpak软件特点 （2）自动的网格划分功能 非结构化的网格技术--可以逼近各种形状复杂的几何，大大减少网格 数 量 ，提高模型 精度。四面体网格--用来模拟形状极其复杂的形状，从而保证求解精度
Airpak软件简介
1.1.2 Airpak软件特点 （4）强大的可视化后置处理 面向对象的、完全集成的后置处理环境 可视化速度矢量图、温度(湿度、压力、浓度) 等值面云图、粒子轨迹图、切面云图、点示踪图等 。
CFD模拟篇-Airpak软件学习
CFD模拟篇-Airpak软件学习1.Airpak软件可以用来做什么？在学习CFD软件之前，我们要知道这个软件能够帮助我们解决什么问题。
Airpak软件其实是一款基于Fluent求解的一款十分强大的软件。
可以用来进行建筑室内空调气流组织模拟，空气品质、自然通风，室外风环境，产品设备散热模拟，客车火车等交通工具室内模拟，室外空调外机气流模拟，室内污染物（co2,甲醛等），厨房通风等等。
模拟完了之后，可以出的结果有：温度、湿度、风速、压力、pmv-ppd(即热舒适度）、空气龄（空气新鲜程度）等等。
这个软件对于暖通专业（建环）或者从事绿建方面工作的人使用的比较多，当然在其他行业也会用的到。
对于设计院或者绿建单位，要用他出一些前期的可研报告、建筑设计评估和优化，对于科研单位，主要用于科学研究。
2.如何学习CFD如何学好CFD，对于这个问题，其实我觉得没有什么特别好的捷径。
我们要做的是，正确的方法和努力勤奋，少走弯路。
2.1软件底层逻辑在学习任何一个CFD软件之前，你首先要了解这个软件运行的底层逻辑是什么，他是基于什么原理，弄明白了这个道理，你学习来才不会费劲。
比如Airpak是基于"object"的建模方式，fluent求解器运行的，而ICEM是基于拓扑结构的建模方式。
很多人在学了gambit后，再来学习ICEM，大半年过去了，ICEM还是没有摸着门道，特别痛苦，回头接着学习gambit。
这是因为这2个软件建模的方式是不一样的，所以思维没有转换，学起来也很难。
掌握了大的学习思维之后，我们最重要的是要有一条系统的科学学习方法。
2.2理论知识的掌握在学习具体软件之前，你需要掌握CFD模拟的一些基本知识比如什么是湍流方程、网格划分的目的、什么是后处理，这些知识是你学习软件之前必须掌握的，也是根基。
那如何学习这些知识呢，你可以看看很多CFD相关的书籍，一般第一章都会介绍一些。
如果你觉得看书麻烦，可以关注某公众号：七师兄课堂，里面有CFD公开课的讲解和文章。
airpak建模问题求助
airpak建模问题求助1.airpak中有hood,vent,opening。
那么对于一个没有新风的内部循环系统怎么表现了。
例如，普通的家用空调房间，其中是一个柜式空调，送风和回风都在机箱上，我是画两个ope ning吗，一进一出？---不是很清楚，没做过。
不过，如果我做得话，会画两个vent，一进一出，但他们的边界条件是不一样的。
opening一般模拟窗户、门等大型的开口；---对于室内循环，应该用使用Recirculation Openings ，当然也可利用两个Opening来代替，用Recirculation的好处是supply和exhaust必然是相同的。
至于vent和opening 的区别，我认为主要在于vent可以定义阻力系数，无法直接给定风口的速度，而opening 恰恰相反。
事实上，有些情况下两者可以互相替换。
而hood不过是由一些基本组件block、fan、partation 等做成的part，完全可以自己来做，个人认为用处不大。
---对于室内内部循环系统，这个airpak当然是可以处理的。
正如你想的，你可以开两个o pening，其中送风口可以定义送风速度，当然你也可以定义其为一个fan，则变化更多，你可以定义不同的diffuser类型。
会风口就定义为一个opening即可。
---关于opening和vent的问题，chabbage的解释可能会引起误解。
实际上, vent诗通常只用在边界上的，这个边界不仅仅是房间的边界，也包括房间里一个hollow的block的边界，比方说这个市内空调机，假如你将其设定为一个hollow的block,那么在他的边界面上就可以定义vent. opening是不可以定义阻力，但是它是定义控制体内不开口的部件，如果有阻力在上面，那就使用resistance.www.2.airpak可以表现管道吗？因为很多风口就在管道上，空气沿管道流动，由于内外压差的存在，又送风口喷出，那么，如果不表现管道的话，送风口的边界条件似乎不好确定。
【资料】Airpak中文帮助文档(1.7部分)
Airpak中文帮助文档（1.7部分）此文翻译来自Airpak帮助文档1.7部分通过1.7部分，你将使用Airpak 建立一个问题、解决一个问题以及输出结果。
这是 对Airpak 特点的基础介绍。
如有疑问可参考Airpak帮助文档的相关部分1.7 示例在下面的示例中，你将使用Airpak建立一个问题、解决一个问题以及输出结果。
这是对Airpak特点的基础介绍。
使用指南中的例子将提供更完整的程序特点。
1.7.1 问题描述图1.7.1显示的所要解决的问题。
房间中包含了一个开放的进风口、一个排气口和一个恒定温度的墙。
房间的长是4.57 m，宽是 2.74 m，高是2.74m。
房间外测量值是0.92 m ×0.46 m，同时引入一个冷空气射入房间使得空气流动。
排气口的尺寸是0.91 m×0.45 m。
惯性的力量、浮力的力量以及湍流混合的相互作用对所提供的空气的渗透及路径有着重要的影响。
1.7.2 主要的过程图1.7.1显示的问题是一个稳定通风的情形。
边界温度以及速度是被定义的。
示例中的步骤简要如下：z打开和定义一项工作z调整默认房间大小z对于一个房间生成一个进风口（opening）、排气口（vent）以及墙z生成网格z计算z检查结果1.7.3 开始一个新工作启动Airpak（1.5节）。
图1.7.2.显示的是【Open job】面板。
在【Select the job to open】文本显示框中路径的最后将/sample写上。
点击【Accept】打开一个新工作。
Airpak将生成一个10 m×3 m×10 m默认房间，同时在图形窗口显示房间。
你可以使用鼠标左键围绕一个中心点旋转房间，或者使用鼠标中间键你可以将房间转移到屏幕的任意一点上。
使用右键放大或缩小房间。
为了将房间回复的默认方位，点击【Options】菜单下【Orient】，在下拉菜单中选择【Home】。
1.7.4 定义工作通过定义房间的种类和设置环境温度来开始工作。
airpak3.0帮助文件第一部分中文tutorial-guide(中文)
帮助文件办公室通风简介：这篇教程演示了如何使用Airpak在电脑上创建有两个人工作的办公室模型。
教程中你将会了解到：1.打开一个新的任务2.电脑模拟相对湿度分布的设置3.创建blocks，openings，vents，partitions和walls4.创建辐射影响的模型5.改变电脑计算的迭代次数〔即为模型的细腻光滑程度，迭代次数越高模型效果越佳〕6.初步计算出一个结果7.检查模型外表的轮廓和物体外表的迭量，以及横断面图8.跟踪空气入口粒子流轨迹9.通过仿真计算检查房间里舒适度的预测平均值〔PMV-同一环境下绝大多数人的热感觉〕和预测不满百分比〔PDD-同环境下人群对热环境不满的百分比〕先决条件：本教程假设你对Airpak软件没有太多经验，但是相对较熟悉软件界面，假设不是请检阅第一张用户指南。
问题描述：该待仿真办公室共分为两大部分，每一部分包含一个坐在电脑前办公的人。
如图1.1 。
同时该办公室还有六个荧光灯、暖气、新风入口、回风口、窗户等。
通过对办公室外表温度和空气流速的剖面仿真，我们可以直观了解办公室整体的舒适度。
图：通风问题所研究的办公室的几何参数步骤1：打开并定义一个新的工作1.启动Airpak，当软件打开后会主动弹出NEW/EXISTING选项卡。
2.单击NEW选项，软件会开始一个新的任务，同时NEW project选项卡将会打开。
(a)你可以为你的任务起一个名称，并将其填写在Project旁边的窗口中。
你可以为此案例命名OFFICE。
(b)点击Create创建。
Airpak会默认创建一个尺寸为10*3*10的房间，并放置在图形窗口内。
你可以使用鼠标左键围绕一个中心点旋转物体，还可以用鼠标中键将它移动到任意一点，鼠标右键则可以放大缩小视窗选择进入或者退出房间。
如果想把房间调整到默认位置，点击界面上方的选项Orient在弹出的菜单中点击Home position。
3.修改默认房间尺寸，设置室内空气属性并打开理性气体定律(a)在Basic parameters基本参数面板，在Species〔种类〕一栏选择ON，并点击旁边的Edit开始编辑。
Airpak使用简介
Atmospheric Boundary Layer
Thanks
情况设置 求解设置
材料库
组 后处理 垃圾箱 非激活 模型元件
建模基本步骤
• 1、设置基本参数（basic parameters） • 2、建立或导入体块（block） • 3、设置计算域（room）大小：迎风面放3倍宽度，背风面 放3～6倍，两边放3倍左右，高度放3倍左右 • 4、建立风场 • 5、划分网格 • 6、迭代计算 • 7、截平面，导出数据、云图等
设置基本参数
I. 计算模型内容选择 II. 重力方向 III.北向
CAD模型导入
具体方法： I. 在CAD中建立体块，输出： ACIS(*.sat)格式； II. 在gambit中打开已保存的*.sat文 件，输出成IGES文件，保存为 *.igs格式； III.在airpak中，在model→ CAD data中打开*.igs格式文件。 IV. 不勾选Use CAD surface directly V. 点击block按钮，根据下方提示， 左键选择face，完毕点击鼠标中 键。
Airpak 演示
装使用
• 安装路径要在英文目录下（最好在盘符下） • 安装文件中的License（授权文件破解）放入：C:\Fluent.Inc\license\ • 文件路径要在英文目录下（否则无法生成网格） • 使用时关闭有道、灵格斯的屏幕取词
菜单栏
建立风场
I. 进口设置成大气层边界。在 model:Macros:atmospheric boundary layer中设置，选风向 和速度，profile direction选 竖直方向的坐标轴 II. 出口设置成openings:pressure 选ambient III.其余两边以及顶部天空设为 wall,symmetry
airpak气流组织模拟教程教程
Airpak气流组织模拟教程编制人：张占莲2015-9-15案例：以广州某办公室房间为例，房间尺寸6m×8m×4.5m，室内通风采用同侧侧送风，上送下回送风方式，送风量1800m³/h，送风温度18℃，广州夏季室外干球温度34.2℃。
室内各物体尺寸、数量及边界条件设置如下表1所示：表1 边界条件设置名称尺寸数量边界条件送风口0.5m×0.2m2个速度入口，2.5m/s 人0.4m×0.35m×1.73m2人热源，75W灯 1.2m×0.2m×0.15m3个热源，40W电脑0.4m×0.4m×0.4m2台热源，173W回风口0.5m×0.2m2个自由出口桌子 1.5m×4m×1.05m1个——北外墙————定壁温，34.2℃1.建模1）打开软件，新建工程。
注：保存路径及工程名称中不要出现中文，中文无法识别。
2）调整房间模型尺寸：Model Room Edit可更改odject名称调整尺寸大小、坐标位置：Geometry可根据个人习惯通过输入起点/终点或起点/长度来确定坐标位置。
3）建立灯、人体、电脑等模型：Creat b locka.创建灯具模型修改block名称：lamp输入坐标尺寸定位a .创建灯具模型：在properties 中修改属性，定义热源。
将灯简化为长方体的固体block定义热源40W利用copy object 可复制灯具模型。
复制数量偏移量b.创建简易桌子模型（可无）采用固体block 创建桌子模型，因桌子并非热源散发源，桌子模型可有可无。
（这里仅作为障碍物）c.创建电脑模型步骤：◆简化为固体的block；◆修改名称为com.1；◆输入坐标定位；◆定义热源属性：173W；◆Copy object命令，设置偏移量。
d.创建人体模型步骤：◆可直接使用自带人体模型，也可将人体简化为长方体的固体block；◆修改名称为person.1；◆修改尺寸，人体为坐姿；◆定义热源属性：75W；◆Copy object命令，设置偏移量。
Airpak使用简介
情况设置 求解设置
材料库
组 后处理 垃圾箱 非激活 模型元件
建模基本步骤
• 1、设置基本参数（basic parameters） • 2、建立或导入体块（block） • 3、设置计算域（room）大小：迎风面放3倍宽度，背风面 放3～6倍，两边放3倍左右，高度放3倍左右 • 4、建立风场 • 5、划分网格 • 6、迭代计算 • 7、截平面，导出数据、 model:Macros:atmospheric boundary layer中设置，选风向 和速度，profile direction选 竖直方向的坐标轴 II. 出口设置成openings:pressure 选ambient III.其余两边以及顶部天空设为 wall,symmetry
设置基本参数
I. 计算模型内容选择 II. 重力方向 III.北向
CAD模型导入
具体方法： I. 在CAD中建立体块，输出： ACIS(*.sat)格式； II. 在gambit中打开已保存的*.sat文 件，输出成IGES文件，保存为 *.igs格式； III.在airpak中，在model→ CAD data中打开*.igs格式文件。 IV. 不勾选Use CAD surface directly V. 点击block按钮，根据下方提示， 左键选择face，完毕点击鼠标中 键。
Airpak 演示
董 剑 2013年10月26日星期六
安装使用
• 安装路径要在英文目录下（最好在盘符下） • 安装文件中的License（授权文件破解）放入：C:\Fluent.Inc\license\ • 文件路径要在英文目录下（否则无法生成网格） • 使用时关闭有道、灵格斯的屏幕取词
菜单栏
Atmospheric Boundary Layer
airpak33问题总结
公告：TopEnergy绿色建筑版主招募计划第一章AirPak版讨论精华内容(33问）----整理版1.请教一下在airpak中物体的散湿量怎么输入，特别是人体？----直接在人体上加了opening，也就是和fluent的处理方法是相同的。
人体散湿量是一个比较烦的问题，一般情况计算的稳态问题，要求这人长期在一个地方不动，这其实与实际情况不太相符。
散湿量是可以定义到一个prism的source上的，单位是kg/s.但是直接用airpak中的人的话，是没有办法设定的。
除非你重新建一个group。
其实用一个长方体就可以代表人了。
用体源项来定义的时间欧就有kg/s的单位了。
用prism的source，不是面的，而是体的。
2.airpak的数据如何提取出来？, `# R6 z) `; u/ b% q0 C airpak的文件如何才能读入到fluent？或者能读入到tecplot 里？report-〉point report，然后输入那些具有代表性的点的参数值，可以创建很多个点，然后勾上write to file，给出文件名称，然后就可以用text文本打开了，不知道这对你有没有用。
How do I include the effect of natural convection in mymodel?. R' u( ^, z: Z2 H. b"File/Problem", toggle the "Gravity vector" and give the gravity value in the appropriate direction. - F2 L1 ^" C( A2 X* ]What is the "Minimum object separation"?; _+ s# ?) W; n9 M2 s+ y' D5 ^7 H# uThis is a value you specify in "File/Configure". It sets a tolerance limit where if any two adjacent faces are separated by a distance less than this tolerance limit, Airpak warns you of the situation. You may choose to cancel the meshing and examine the model for any errors or ignore the warning and go ahead with the meshing. It is not advisable to let Airpak make the changes automatically for it may make many unintended changes. 3 D/ Q2 w; w; o, ^- \"Radiation temperature" is the partial enclosure temperature applied when the default surface-to-surface radiation model is used. When a given surface radiates to some surfaces, normally all of the radiation does not reach these surfaces. The portion of radiation that doesn't reach these surfaces is assumed to go to the ambient maintained at a reference temperature called the"Radiation temperature". 3 t+ a7 N7 R3 d7 Q- t: N1 K5 S1 @+ _3.关于model的问题, k v; a5 N j1 S% W! @0 ~room--当创建一个新文件时，airpak会在图形窗口自动生成一个默认的room，尺寸：10m×3m×10m，显示的是xy平面的视图。
airpak常见问题问与答-整理版
airpak常见问题问与答（一）建模基础1)My model is very complicated, what is the best way to build it ? (3)2)How can I simplify my model? (3)3)How often shall I save? (3)4)I am making models with only small changes between them, shall I save them under different names or get different solutions under the same name? (3)5)My area of interest is not surrounded by walls on all sides, is it OK to use the room walls or should I put openings on these walls? (4)6)Should I include the effect of gravity in my model? (4)7)Should I include the effect of radiation in my model? (4)8)The calculation for the view-factor matrix is taking too long, what is happening? (5)9)How do I decide whether the flow is turbulent or laminar? (5)10)Is is easier to import a model from a CAD package or construct the model inside Airpak? (5)11)What are the CAD package files I can import into Airpak? (5)12)What units should I use? (6)13)How do I take the effect of elevation into account? (6)14)My model is symmetric but my solution is not, what is the reason? (6)15)What is a typical magnitude of flow velocity due to (pure) natural convection? (6)16)Can I predict condensation in a room? (6)17)My Airpak jobs are taking up too much disk space, what should I do? (7)18)How can I free-up disk space without deleting model, mesh and postprocessing files?719)What are the three most essential files of an Airpak model? (7)20)What does "pack" and "unpack" mean? (7)21)How do I print out an Airpak model? (7)22)Where do I define my units? (8)23)How do I run a time-dependent or unsteady simulation? (8)24)What are initial conditions? (8)25)What is the "Minimum object separation"? (8)26)What is the meaning of "Radiation temperature" on the "Problem/Setup" menu? (9)27)My Airpak model is so cluttered, what should I do to see the model more clearly? (9)28)How can I suppress the view of objects in Airpak? (9)29)Sometimes the dimensions of objects contain too many decimal places: Is there a way to avoid this situation? (9)30)How do I move, copy or scale a group of objects at the same time? (9)31)How do I move a group of objects using the mouse? (10)32)How can I change the specifications (material type, power, etc.) of a group of objects in my model? (10)33)What is a part? (10)34)How can I scale an object with different scale factors in each of the coordinate directions? (10)35)How do I reverse the order of object creation? (10)36)How do I change the default values of material properties? (11)37)How do I define new materials in my database? (11)38)How do I view my model in shaded form? (11)39)What is the difference between "Device" and "Approach" methods in the calculation for pressure losses in vents and resistances? (12)40)What is a macro? (12)41)I have created a heat sink macro and want to send it to my colleague. What is the quickest option? (13)42)How do I apply a transient thermal loading (power) to my block? (13)43)Can I prescribe several transient power loading segments to my model? (13)44)I am only interested in getting the flow distribution and not the temperature. How doI solve for the flow distribution only? (13)45)I have obtained the flow distribution from a previous run and want to solve my model for another power loading. Can I only solve for temperature? (13)46)I am modeling a pole-mounted enclosure and want to include the effect of solar loading, what is the best approach? (14)47)I am modeling external airflow. How large should my room be? (14)48)Can I build my model in inches and use the SI system of units to specify the other parameters such as conductivity, power, etc.? (14)49)The origin of my room is a non-zero number, can I convert it to (0,0,0)? (14)50)I am modeling a telecom rack and do not know whether I should use a plate or PCB for my motherboard? (14)51)How can I model small air gaps or interface material between surfaces? (15)52)What is the difference between conducting thick partitions and contact resistances?1553)My region of interest is not a rectangular prism, how can I construct the room in Airpak? (15)54)When should I use hollow blocks? (15)55)I have a table of volume flow vs pressure data for my fan, can I load this data directly, instead of entering it manually? (15)56)How do I take the effect of elevation into account? (16)57)How do I determine the operating point of a fan? (16)58)What is the difference between blocks and partitions? (16)59)What is the difference between internal and external fans? (16)60)Is there flow through the hub of my fan? (17)61)How do I incorporate a swirl effect into my fan flow? (17)62)Can I use partitions on the sides of the room? (17)63)What is the difference between partitions and walls? (17)64)How do I specify a non-uniform conductivity to my blocks or partitions? (17)65)I am specifying power on a block. Can I specify the power to the volume as well as to the faces? (18)66)When I write out an IGES file from IDEAS, Airpak can not read it. How can I fix this?1867)Is it possible to copy one object type to another? (18)68)What is the difference between "Total heat" and "Fixed value" in "Model/Source"?1969)How do I calculate the thermal resistance given conductivty data? (19)1)My model is very complicated, what is the best way to build it ?Start simple. First include the most important items such as the cabinet, big power devices, fans, vents and openings, if any. For first level analysis, ignore small details. For example, you may smear power sources over blocks or plates, instead of modeling them in detail using small blocks. Make sure the simple model runs well and the solution makes sense. You can then gradually include more details into your model. It is absolutely essential that you build your model step by step!2)How can I simplify my model?To simplify your model, you may consider:reducing your model by using symmetry conditionsusing planar objects instead of thin objectsbreaking the model into two or more smaller modelsneglect small curves, small protrusions, etc.aligning nearly-aligned faces of objects3)How often shall I save?As with all software products, it is advisable to save as often as possible. This will ensure that your data is not lost in the event of machine or system failure. In particular, it is important to save the model before starting the solution process. So, if you need to terminate your solution process for any reason using the control C option, the latest model will be saved.4)I am making models with only small changes between them, shall I savethem under different names or get different solutions under the samename?If the changes are geometric (so that the mesh between the two is different) you should save them under different names. For example, if you have a model named job1, you may copy it to job2. Then make the changes you want in job2 and run it. However, if you are just changing the ventilation flowrate or inlet temperature (so that the mesh is the same), you may either save it to a different name, or, if you wish to use the Restart option, run a second solution under the same name.5)My area of interest is not surrounded by walls on all sides, is it OK to usethe room walls or should I put openings on these walls?In general, it is not necessary to put openings on all room walls. It is sufficient to put openings on the walls which are perpedicular to the dominant flow direction(s). However, make sure that the walls that don't have openings are far enough so that they don't influence the flow distribution near the area of interest.6)Should I include the effect of gravity in my model?Generally, you should include gravity because room air flows are relatively low velocity flows and the buoyant plumes from local heat sources or non-isothermal behavior of air jets can be important to model. However, if you have an isothermal application, gravity will have no effect.7)Should I include the effect of radiation in my model?In most forced convection cases (where fluid is pushed through by fans, pumps, etc.), the effect of radiation is under 2-5% and may be ignored. In some cases, the effect may be of the order of 10% or even greater and must be included. Examples are:natural convection casessealed systemsisolated hot components radiating to nearby objects or the ambientlarge areas radiating to the ambientsolar loadingIt is often a good practice to ignore the effect of radiation in the first level of analysis and include it later, in the final stages of analysis.8)The calculation for the view-factor matrix is taking too long, what ishappening?Your model probably has a large number of objects. Even if the number of objects participating in radiation is small, Airpak still involves the other objects in the calculation. One way of speeding the calculation is to construct the radiation.ff file from a simpler Airpak model and use this file in the actual model. To construct the simpler model, make a copy of the actual model and delete some components that are either not participating in radiation or have minimal effect on radiation. Then compute the view factor matrix and use the resulting radiation file (radiation.ff) in the actual model. Another option is to activate the discrete ordinates radiation model which alleviates the need for a time-consuming view-factor calculation although the ensuing flow solution will require more computational time.9)How do I decide whether the flow is turbulent or laminar?Airpak estimates the non-dimensional numbers which will help you determine whether the flow is turbulent or laminar. For forced convection problems, the number to watch is the Reynolds number, for natural convection problems, look at the Rayleigh number. You can look at the estimates of these numbers by clicking the "Reset" button in Solution/Setup. The numbers as well as the recommended flow setting will be displayed in the messages window. In general, the flow is considered tubulent if the Reynolds number is greater than 5000 or the Rayleigh number if greater than 1e+8. The user is advised to use his/her own judgement as to this setting, particulary when the flow regime is in the transition region (between laminar and turbulent).10)Is is easier to import a model from a CAD package or construct the modelinside Airpak?It varies from case to case. In many cases, you can easily and rapidly construct your model in Airpak. In some cases, however, it may be advantageous to import from CAD packages directly. This is true in situations where transfering the dimensions (sizes and locations) is time consuming.11)What are the CAD package files I can import into Airpak?You can import an Airpak model from Pro/E directly. You can also import IGES files from any CAD package and DXF files from AutoCad.12)What units should I use?You can use any system of units or a combination of them (e.g., SI, English system, etc.). You can define your units in the "Edit unit definitions" under "File/Configure". You can also define units locally for any particular object (dimensions, properties, etc.). However, in general, it is advisable to use a consistent set of units so that the possibility of error is minimized.13)How do I take the effect of elevation into account?The effect of elevation can be taken into account by simply altering the density of air in the materials database. The default value of air density can be seen in "Model/Materials". Go to "Fluid/Gases/Air" and enter the new air density for the elevation under consideration. Make sure to click "Update" after editing the material properties.14)My model is symmetric but my solution is not, what is the reason?This is most likely due to one or both of the following reasons:The mesh is not symmetric.The solution hasn't converged..15)What is a typical magnitude of flow velocity due to (pure) naturalconvection?It is of the order of 0.1 m/s.16)Can I predict condensation in a room?In Airpak, you can track water vapor as a species and look at the relative humidity. Although there is no condensation mass transfer model in Airpak, seeing results in which the relative humidity approaches 100% in some areas is a good indication that condensation is likely.17)My Airpak jobs are taking up too much disk space, what should I do?Use "Cleanup" under "File" menu and delete mesh, scratch, and solution files18)How can I free-up disk space without deleting model, mesh andpostprocessing files?You can compress the files using the "Compress" option under "File/Cleanup", or, you can delete the scratch files in "File/Cleanup" and save as much as 20% of the disk space. 19)What are the three most essential files of an Airpak model?They are "job", "model" and "problem". These files contain all the information specified to build the model, such as the size and location of objects, properties of objects, problem setup data, mesh specifications, and solver settings. Any Airpak model must have atleast these three files.20)What does "pack" and "unpack" mean?The "Pack" and "Unpack" facility in Airpak allows you to communicate with Airpak support or with another Airpak user rather easily."Pack" means packaging the component files of an Airpak model (job, model and problem) into one file by tarring and zipping these files. You can send that file to Airpak support or another Airpak user for examination. The packaged file is named "jobname.tzr"."Unpack" means unpacking a packaged job automatically. The unpack routine unzips and untars the zipped and tarred file and saves the component files "job", "model" and "problem" under the the directory "jobname", where jobname is the name of the model specified in the packaged job.21)How do I print out an Airpak model?First display the model in the Airpak inteface the way you want the model to appear in the print (including the size, view, shading, etc.). Then, in the options menu at the far right of the Airpak main inteface, click "Print" and save the image under one of the file formats allowed, e.g. gif, tiff, etc. You can then send the saved file to your printer.22)Where do I define my units?You can define units in "File/Configure". Click "Edit unit definitions" and define the units for any quantity (length, conductivity, power, etc.) and click "Set as default". The units so defined will be applied to any new object introduced into the cabinet. You can also alter the units of any variable of an object by editing the object and changing the unit definitions selected. To do this, just click the unit indicator beneath the quantity under consideration and change it to any other unit in the pick-list. The user also has the ability to simply set the type of units used for the entire problem to SI units or Imperial (English) units.23)How do I run a time-dependent or unsteady simulation?First select "Transient" by going to "File/Problem" and then specify "Start", "End time", "Time step increment", and "Solution save interval" of your simulation. Then go to "Solution/Setup" and specifiy the "Iteration/timestep".24)What are initial conditions?"Radiation temperature" is the partial enclosure temperature applied when the default surface-to-surface radiation model is used. When a given surface radiates to some surfaces, normally all of the radiation does not reach these surfaces. The portion of radiation that doesn't reach these surfaces is assumed to go to the ambient maintained at a reference temperature called the "Radiation temperature".How do I include the effect of natural convection in my model?In "File/Problem", toggle the "Gravity vector" and give the gravity value in the appropriate direction.25)What is the "Minimum object separation"?This is a value you specify in "File/Configure". It sets a tolerance limit where if any two adjacent faces are separated by a distance less than this tolerance limit, Airpak warns you of the situation. You may choose to cancel the meshing and examine the model for any errors or ignore the warning and go ahead with the meshing. It is not advisable to letAirpak make the changes automatically for it may make many unintended changes. 26)W hat is the meaning of "Radiation temperature" on the "Problem/Setup"menu?These are initial values of velocity and temperature that will be assigned to each cell in the mesh to serve as the first guess values for the solver. These are just initial guess values and are replaced by new values after the first iteration is completed. The default initial conditions are sufficient for most cases.27)My Airpak model is so cluttered, what should I do to see the model moreclearly?You can suppress the views of some objects. See the next FAQ on suppressing views for how to do it. You can also use the "Gouraud shading" on a given class of objects (or just one object) to see these objects clearly.28)How can I suppress the view of objects in Airpak?At the top right hand corner of the Airpak interface, there are two columns of boxes. Click on "Visible" and toggle off the object type (e.g. blocks) the views which you want to supress. Note that the object class that is suppressed is still part of the model, it is just not visible. For that reason, it is a good practice to toggle on these objects (after you are finished viewing) so that you don't forget about them. You can also suppress the view of a particular object (rather than a class of objects) by editing that object and selecting "Invisible" under "Shading" in the object edit form.29)Sometimes the dimensions of objects contain too many decimal places: Isthere a way to avoid this situation?Before beginning to build your model, set the "x-grid", "y-grid" and "z-grid" to the minimum decimal place you want to have (for example 0.0001). This will force objects to move or locate with fixed increments and you will not get the unwanted decimals unless you scale the model.30)How do I move, copy or scale a group of objects at the same time?Use the "Groups" option in the "Model" menu to group the objects. You can then move,copy, or scale as you wish. Please refer to the training notes or the Airpak manual for more details.31)How do I move a group of objects using the mouse?Use the "Groups" option in the "Model" menu and group the objects. Then toggel on the "Move group" button and move the group using the mouse (shift + middle mouse button).32)How can I change the specifications (material type, power, etc.) of a groupof objects in my model?First, group all the objects. Then change the specifications of one of the objects. Then use the "Copy parameters" option in the "Groups control" form to copy the specifications from that object (which is highlighted in the Airpak edit form) to all other object in the group. You will see the following messages in the messages window: Copying parameters from ... to ...33)What is a part?A part is an assembly of objects which you create and store that can then be used in different models. To create and store a part, go to "Model/Groups" and make a group and then click "Create part". This will create an internal part, i.e., a part specific to the current model. To create an external part, go to "Parts", under "Model", and highlight the part you have just created. Click "Edit" and then "Write part" in the Parts form. This will open a "Save job" form for you. Save the part (with a given name) inside a directory of your choice.34)How can I scale an object with different scale factors in each of thecoordinate directions?Use the "Move" option in the "Model" menu. Toggle "Scale" and enter scaling factors for each of the three directions. For example entering 0.5, 1.0, 1.0 reduces the X dimension of the object by 50%.35)How do I reverse the order of object creation?You can change the priority values in "Model/Priorities". Objects that were created first have a lower priority number than objects that were created later. By changing these numbers, you can change the order of creation. This in turn affects, among other things, the meshing hierarchy.36)How do I change the default values of material properties?Go to "Model/Materials" and then select "Solid", "Fluid" or "Surface" properties. For example, under "Solid", you can go to "Metals/Alloys" and alter the default propreties of materials such as Al-Extruded, Cu-Brass, etc. Just click "Edit" and alter one or more of the properties. If necessary, you can also define a linear or curve variation of a property value with temperature.37)How do I define new materials in my database?If the new materials to be defined are specific to the current model only, go to "Model/Materials" and add new materials in one of the three catergories available (Solid, Fluid and Surfaces). To do this, select the proper subclass (e.g. "Metals/Alloys" under "Solid") and click "New". Then, click "Edit" and edit the name of the new material and specify its properties.If the new materials to be defined are common to all other Airpak models, you need to create them differently. In this case, create a new Airpak model called "materials" (just the default room is sufficient). Then create new materials following the steps described above and save the Airpak model (called materials). The newly defined materials will then be available to any Airpak model, provided the correct path is specified in "Edit library path" under "File/Configure". To specify the path, type the complete path (to the directory containing the model called materials) in the "Edit entry" and click "Add". For more details, call your Airpak support.38)How do I view my model in shaded form?Go to "view" and select "Gouraud shading" instead of the default "Wireframe" display. In this case, all the objects in the cabinet will be shaded. If you need to shade one class of objects only, go to "File/Configure" and click "Edit graphical styles" and select "Gouraud", instead of "View", for one class of objects (blocks, plates, etc.). It is also possible to have Gouraud shading for one object only. To do this, edit the particular object under consideration and, under "Shading", select "Solid".In my fan curve, the volume flow/pressure numbers are not what I specified in the "Edit" form, what is happening?The numbers are scaled by a factor shown along the axis. For example, 1.5 Pa with a scale factor of 1e2 is equal to 150 Pa.39)What is the difference between "Device" and "Approach" methods in thecalculation for pressure losses in vents and resistances?The two differ in the way the pressure drop is calculated. In the "Approach velocity method", the pressure drop is calculated based on the loss coefficient data provided and the flow velocity approaching the device (vent or resistance); the free area ratio data is not used. In the "Device velocity method", however, the flow velocity through the device is used, as well as the loss coefficient and the free area ratio data provided. The following relationships may be noted:V-dev = V-app/AL-app = L-dev/A**nwhere,V-app = Approach velocityV-dev = Device velocityL-app = loss coeff. based on approach velocityL-dev = loss coeff. based on device velocityA = free area ration = 1 for linear relationship and 2 for quadratic relationship40)What is a macro?A macro is a compact and easy representation of a complex system. Examples are heatsink macros and macros for packages (BGA). Such models may be used when detailed modeling is time consuming and/or impractical.41)I have created a heat sink macro and want to send it to my colleague.What is the quickest option?Save the heat sink macro settings (in the heat sink creation form) and send that file to your colleague. The settings can be saved in a file insied the directory "heatsink_info".42)How do I apply a transient thermal loading (power) to my block?Edit the block and give the Total power. Then select "Transient", instead of "Constant value". Now, click "Edit" and you will need to specify tS and tE (the starting and ending times within which the specified power is on), and the time variation of power with time (Linear, Power law, etc.). Note that you can specify trainsient loading for solid or fluid blocks only. Sources (planar or volumetric) can also be used to specify transient power loading.43)Can I prescribe several transient power loading segments to my model?Yes. For example, you can ramp up the power for 5 minutes, maintain the maximum power for 10 minutes, and ramp down the power for 15 minutes. To do this, use the "Text editor" (under "Piecewise linear") and specify the time-dependent power.44)I am only interested in getting the flow distribution and not thetemperature. How do I solve for the flow distribution only?Go to "File/Problem" and click off "Temperature" in the "Variables solved" option.45)I have obtained the flow distribution from a previous run and want tosolve my model for another power loading. Can I only solve for temperature?Yes. Go to "File/Problem" and click off "Flow (velocity/pressure)" in the "Variables solved" option. In order to use the previous flow solution, you need to use the "Restart" option in "Solution/Solve".46)I am modeling a pole-mounted enclosure and want to include the effect ofsolar loading, what is the best approach?First, you need to calculate the incident flux (from text books) to each of the faces exposed to solar loading. Then, put planar sources on these faces with the appropriate heat flux (power) conditions.47)I am modeling external airflow. How large should my room be?In general, if the building has height H and width W, you would want your room to be at least 5H high, 10W wide, with at least 2H upstream of the building and 10 H downstream of the building. You would want to verify that there are no significant pressure gradients normal to any of the boundaries of the computational domain. If there are, then it would be wise to enlarge the size of your room.48)Can I build my model in inches and use the SI system of units to specifythe other parameters such as conductivity, power, etc.?Yes. You can build your model in inch and still use other system of units for the other specifications.49)The origin of my room is a non-zero number, can I convert it to (0,0,0)? Yes. Use the "Move" command in "Model/Room" and translate the room in the X,Y,Z directions by giving the proper offset.50)I am modeling a telecom rack and do not know whether I should use aplate or PCB for my motherboard?The PCB is a very simple representation of a printed circuit board. For first level calculations and approximate answers, the use of the PCB is acceptable. If more detailed results are desired, plates or blocks should be considered, perhaps with discrete chips (blocks or sources) attached to the surfaces. The advantage here is that the conductivity of the board can be modified in each direction to take into account the multi-layered nature of the board. PCBs do not have inherent conducivity. In addition, plates and blocks allow the specification of other effects such as radiation.。
Airpak学习教程（翻译50页）
Airpak 2.0 使用指南办公室通风∙简介∙前言∙问题描述∙第一步：打开并定义一个新任务∙第二步：创建模型∙第三步：加入辐射和模型∙第四步：计算网格∙第五步：检查风状况∙第五步：将模型保存到任务文件中∙第六步：计算一个解决方案∙第七步：检查结果∙汇总∙参考文献简介这篇教程演示了如何使用Airpa k在计算机上创建有两个人工作的办公室的模型教程中你将学会：∙打开一个新任务∙包括计算机模拟相对湿度影响的分布∙创建blocks, openin gs, vents, partit ions,和 walls∙创建辐射影响的模型∙改变计算机计算的迭代次数∙计算一个结果∙检查模型表面轮廓和物体表面的矢量，以及横断面图∙空气入口的粒子流轨迹通过计算机计算检查房间里的舒适度的预测平均值(PMV)和不满百分比（PPD）必装条件这个教程假设你对air pak没有经验，但是你很熟悉接口，如果您不是，请检查第一张的用户指南问题描述这个办公室分为两个部分,每部分包含一个人，坐在电脑前工作,如图 1.1。
这个办公室还包括六个荧光灯、暖气片、空气入口、回风口,窗户。
表面温度和空气流速剖面,目的是为了确定整个舒适的房间。
Table1.1:几何参数,导热性，窗户和扩散器的流动边界条件尺寸温度速度13.5 C 0.85 m/s进气口扩散0.2 m 0.3 m30.9 C ---窗户3.65 m 1.16 mTable1.2:热源的尺寸和性能热源Size Power1500 W墙挂式取暖1.2 m 0.1 m 0.2 m75 W人0.4 m 0.35 m 1.1 m108 WComput er 10.4 m 0.4 m 0.4 mComput er 2173 W0.4 m 0.4 m 0.4 m34 W灯0.2 m 1.2 m 0.15 mFigure 1.1:通风问题所研究的办公室的几何参数Step 1: Open and Define a New Job1.启动airp ak,如简介1.5中说明的那样，打开任务面板将自动开启2.为你的任务取一个名字(a)In the Select the job to open text box, type /office at the end of the path.在选择任务打开文字框内，输入/office在路径的最后(b)ClickAccept. 点击接受Airpak will create a defaul t room with the dimens ions10 m 3 m 10 m, anddispla y the room in the graphi cs window.Airpak将创建一个默认的尺寸为10x3x10的房间，并放置在图形窗口内。
CFD流体模拟篇-Airpak软件学习
CFD模拟篇----Airpak软件学习有很多想学习CFD的学员咨询我，如何才能快速的熟练掌握CFD软件。
对于刚学习，没有任何基础的学员，我一般会推荐他们学习一些比较容易上手的软件，比如本文我要重点说的Airpak软件。
后续的文章中我会重点总结一些学员，在学习过程中遇到的问题以及解决办法。
1.Airpak软件可以用来做什么？在学习CFD软件之前，我们要知道这个软件能够帮助我们解决什么问题。
Airpak软件其实是一款基于Fluent求解的一款十分强大的软件。
可以用来进行建筑室内空调气流组织模拟，空气品质、自然通风，室外风环境，产品设备散热模拟，客车火车等交通工具室内模拟，室外空调外机气流模拟，室内污染物（co2,甲醛等），厨房通风等等。
模拟完了之后，可以出的结果有：温度、湿度、风速、压力、pmv-ppd(即热舒适度）、空气龄（空气新鲜程度）等等。
这个软件对于暖通专业（建环）或者从事绿建方面工作的人使用的比较多，当然在其他行业也会用的到。
对于设计院或者绿建单位，要用他出一些前期的可研报告、建筑设计评估和优化，对于科研单位，主要用于科学研究。
2.如何学习CFD如何学好CFD，对于这个问题，其实我觉得没有什么特别好的捷径。
我们要做的是，正确的方法和努力勤奋，少走弯路。
2.1软件底层逻辑在学习任何一个CFD软件之前，你首先要了解这个软件运行的底层逻辑是什么，他是基于什么原理，弄明白了这个道理，你学习来才不会费劲。
比如Airpak是基于"object"的建模方式，fluent求解器运行的，而ICEM是基于拓扑结构的建模方式。
很多人在学了gambit 后，再来学习ICEM，大半年过去了，ICEM还是没有摸着门道，特别痛苦，回头接着学习gambit。
这是因为这2个软件建模的方式是不一样的，所以思维没有转换，学起来也很难。
掌握了大的学习思维之后，我们最重要的是要有一条系统的科学学习方法。
2.2理论知识的掌握在学习具体软件之前，你需要掌握CFD模拟的一些基本知识比如什么是湍流方程、网格划分的目的、什么是后处理，这些知识是你学习软件之前必须掌握的，也是根基。
RFPA常见问题回答
版本问题1Y 方向应力值和X 方向应力值分别代表什么意思？2绘制多边形的时候怎么老是停不下来，一直让输入坐标，这个一般是怎么弄的3.二维版本快捷查看材料属性方法4做煤层分步连续开挖的时候 煤层挖掉以后 顶板开始弯曲下沉但是随着计算步的增加 顶板会“侵入”到底板里面 可以看到顶底板有重叠 这个问题怎么解决 用的试用版的基本版5四周都选择边界加载的应力加载，得不到解的原因。
1读孔隙水压力失败2.2D 渗流版渗流空洞载荷如何删掉1需注意基本问题：（1）结构化生成器中密度要设定（一般在2500-2700）；（2）施加载荷时，当载荷为0时，不能直接写0，改成0.000001即无限接近于0的数值；（3）控制信息中简化模型选“平面应变模型”2动态版预查看振动波在岩土里的衰减规律1.二维1.0版本外载荷施加方向二维基本版二维渗流版二维动态版.0版本2.RFPA1.0版本如果想画的图片在计算前没有选中，计算后想得到后处理图像怎么办？3X方向load与；Lateral pressure区别二维1.0版本1终点初始值是什么意思？2自重单位N/mm33在安装路径没有出现中文和空格的情况下，仍出现2三维版本多单元信息提取3添加节理操作4RFPA中输出的的最大主应力图和最小主应力图，与岩石力学定义相同（压为正、拉为负）5屏幕一直闪综合问题6试块加卸载7多单元信息提取8二维对于单元格数超过50w的控制信息设置9建模时倾斜煤层、岩层如何做出来的10.3D版本的单轴加载方向11.2Dv1.0版本，多单元信息提取12.二维和三维软件应力/位移-加载步曲线，0点取值不一样问题。
三维应力-加载步曲线 二维应力-加载步曲线13.三维后处理应力值指14步中步是什么意思15cmd命令调用16声发射的单位是什么17声发射出现负值原因18为什么RFPA单元网格划分选择正方形。
19声发射中红白球分别代表什么意思？20软件在计算过程中提示“停止计算”“无法获取节点”信息等提示但关闭窗口还能继续计算。
Airpak学习教程
Airpak 2.0 使用指南办公室通风∙简介∙前言∙问题描述∙第一步：打开并定义一个新任务∙第二步：创建模型∙第三步：加入辐射和模型∙第四步：计算网格∙第五步：检查风状况∙第五步：将模型保存到任务文件中∙第六步：计算一个解决方案∙第七步：检查结果∙汇总∙参考文献简介这篇教程演示了如何使用Airpak在计算机上创建有两个人工作的办公室的模型教程中你将学会：∙打开一个新任务∙包括计算机模拟相对湿度影响的分布∙创建blocks, openings, vents, partitions, 和 walls∙创建辐射影响的模型∙改变计算机计算的迭代次数∙计算一个结果∙检查模型表面轮廓和物体表面的矢量，以及横断面图∙空气入口的粒子流轨迹∙通过计算机计算检查房间里的舒适度的预测平均值(PMV)和不满百分比（PPD）必装条件这个教程假设你对airpak没有经验，但是你很熟悉接口，如果您不是，请检查第一张的用户指南问题描述这个办公室分为两个部分,每部分包含一个人，坐在电脑前工作,如图 1.1。
这个办公室还包括六个荧光灯、暖气片、空气入口、回风口,窗户。
表面温度和空气流速剖面,目的是为了确定整个舒适的房间。
Table 1.1:几何参数,导热性，窗户和扩散器的流动边界条件尺寸温度速度13.5 C 0.85 m/s进气口扩散0.2 m 0.3 m30.9 C ---窗户3.65 m 1.16 mTable 1.2:热源的尺寸和性能热源Size Power1500 W墙挂式取暖1.2 m 0.1 m 0.2 m75 W人0.4 m 0.35 m 1.1 m108 WComputer 10.4 m 0.4 m 0.4 m173 WComputer 20.4 m 0.4 m 0.4 m34 W灯0.2 m 1.2 m 0.15 mFigure 1.1:通风问题所研究的办公室的几何参数Step 1: Open and Define a New Job1.启动airpak,如简介1.5中说明的那样，打开任务面板将自动开启2.为你的任务取一个名字(a)In the Select the job to open text box, type /office at the end of the path.在选择任务打开文字框内，输入/office在路径的最后(b)Click Accept. 点击接受Airpak will create a default room with the dimensions 10 m 3 m 10 m, anddisplay the room in the graphics window.Airpak将创建一个默认的尺寸为10x3x10的房间，并放置在图形窗口内。
Airpak中文学习案例（含软件操作步骤）-CFD模拟教程-自然通风室内环境模拟
Airpak中⽂学习案例（含软件操作步骤）-CFD模拟教程-⾃然通风室内环境模拟Airpak软件中⽂学习案例（含软件详细操作步骤）建筑边庭对室内环境的影响-CFD模拟分析⽬录01篇建模问题 (3)1.1模拟概况 (3)1.2简化模型 (5)1.3⽤airpak建模 (5)1.4airpak建模步骤 (6)02篇⽹格⽣成篇 (9)2.1⽹格⽣成详细步骤 (9)2.2⽹格检查 (11)03篇条件设置 (12)3.1边界条件设置 (12)3.2初始参数设置 (15)3.3残差和计算参数设置 (16)04篇模拟后处理 (17)05篇边庭模拟⼩结 (21)01篇建模问题1.1模拟概况本⼯程是某地区⼀栋坐北朝南的办公楼，东侧是贯穿⼀层的边庭，主要功能为通风采光，南侧是⼀个内部⾛廊。
办公楼⼀共2层，上下层都为办公室、会议厅，建筑⾯积⼤约3000平⽅⽶。
室内布置主要为桌椅、空调等（实际模型详见下⽅图纸）。
本⼯程主要通过CFD模拟软件Airpak对建筑边庭进⾏研究，分析边庭（中庭）对建筑室内的通风效果通过温度、湿度、风速、空⽓龄、PMV-PPD等指标参数，评价室内通风效果。
本教程由百度账号：a⾕⾬c燕,第七代师兄，独家原创分享，未经许可不得转载。
⾸次发布在百度⽂库模拟⼯况为：(1)冬季⽆空调时，边庭对室内通风、热舒适度的影响。
(2)冬季有空调时，边庭对室内通风、热舒适度的影响。
1.2简化模型拿到⼆维图纸或三维图纸后，建模的思路是先熟悉图纸，⼆维和三维图纸都看⼀遍，了解图纸中的建筑和物体的布局，其次结合CFD 模拟⼯况的要求，对建筑模型进⾏必要的简化，最后依据图纸信息进⾏建模。
例如本⼯程，是⼀个办公楼，要做如上2个⼯况的模拟，拿到图纸后熟悉每个房间的布局，⾥⾯有桌椅、⼈体、玻璃幕墙等。
对⾥⾯的⼈体进⾏舍弃，边庭处的沙⼟、植物对⽓流影响不⼤的也进⾏舍弃，最后得到⼀个模拟的⼤致布局。
脑中有了这些模型后，可以⾃⼰画⼀下，也可以建模的时候⼀遍勾勒，⼀遍看图。
Airpak模拟48讲高级班-CFD数值模拟辐射空调-瞬态模拟-建筑室外空调机散热fluent
CFD模拟课程-Fluent-辐射空调-自然通风-污染物扩散-瞬态模拟 | CFD理论知识篇 | 流体知识篇 | 10大模拟专项案例 | 常见问题解答篇 |
主 讲 人,仅供个人学习，侵权必究
COMPANY
表面力
(7)表面力:大小与表面面积有关而且分布作用在 流体表面上的力称为表面力。表面力按其作用 方向可以分为两种:一种是沿表面内法线方向的 压力,称为正压力;另一种是沿表面切向的摩擦力, 称为切应力。
湍流（紊流）
（9）因为湍流现象是高度复杂的,所以至今还没有一 种方法能够全面、准确地对所有流动问题中的湍流现 象进行模拟,在涉及满流的计算中,都要对湍流模型的模 拟能力及计算所需系统资源进行综合考虑后,再选择合 适的清流模型进行模拟。 CFD模拟中采用的激流模拟方法包括Spalar-Allmars 模型、standard k-epsilon 模型、RNG (重整化群) kepsilon模型、 Realizable k-epsilon模型、v2-f模 型、RSM (ReynoldsSress Modtel,雷诺应力模型)模 型和LES (Large Eddy Simulation,大涡模拟)方法。
03 课 程 目 录
41节 正压通风-风量平衡
42节 探针功能和数据报告
43节 初始化设置问题
44节 案例结果第二次打不开的问题
45节 自然排烟问题 46节 湍流方程选用原则
辐射空调案例
47节 软件运行故障问题
48节 课程总结及课程计划
瞬态模拟案例
复杂模型建模
C F D 理 论 基 础 TEACHING CONTENT
CFD理论知识、流体概念、公式方程、边界条件、数 值模拟方法和分类、CFD算法。
航空领域中的飞行器设计软件使用中常见问题解析
航空领域中的飞行器设计软件使用中常见问题解析飞行器设计软件在航空领域中扮演着重要的角色。
它们提供了许多功能和工具，用于帮助工程师们设计、模拟和优化飞行器的各个方面。
然而，在使用这些软件的过程中，工程师们常常会面临一些常见的问题和挑战。
本文将针对这些问题进行解析和探讨。
一、软件安装和配置问题在使用飞行器设计软件之前，工程师们首先需要进行安装和配置。
这个过程可能会涉及到一些技术问题，如操作系统的兼容性、硬件要求等。
此外，一些软件还需要许可证或注册码才能正常使用。
如果在安装和配置阶段遇到问题，工程师们可以参考以下几点解决方案：1. 确保操作系统符合软件要求：在安装软件之前，仔细阅读软件的系统要求，确保操作系统和硬件配置满足要求。
2. 检查网络连接和许可证：部分软件需要联网激活或获取许可证，确保网络连接正常，并仔细阅读软件提供的许可证激活步骤。
二、数据导入和导出问题飞行器设计软件通常需要使用各种数据，如CAD图纸、模型文件、流体动力学数据等。
工程师们在导入和导出这些数据时可能会遇到一些问题，比如格式不兼容、数据丢失等。
以下是一些建议来解决这些问题：1. 检查数据格式：在导入数据之前，确认数据的格式是否符合软件要求。
有时，软件可能只能接受特定格式的数据。
2. 使用中间格式：如果导入或导出的格式不兼容，可以尝试在中间使用一种通用的格式，如STEP文件。
三、模拟和优化问题软件中的模拟和优化功能是飞行器设计过程中的关键部分。
在使用这些功能时，工程师们可能遇到一些问题，如计算时间过长、结果不准确等。
以下是一些建议来解决这些问题：1. 确认网格划分和边界条件：在进行模拟之前，确保数值网格的划分和边界条件的设置正确。
这些参数可能会对计算的精度和收敛性产生重要影响。
2. 优化计算设置：对于复杂的模拟和优化问题，可能需要调整软件的计算设置，如收敛准则、步长等。
这些设置可能会对计算速度和结果的准确性产生影响。
四、学习和培训问题飞行器设计软件通常具有复杂的功能和工具，需要进行学习和培训才能充分发挥其潜力。
最新airpak-建筑群流场模拟中边界条件的设定汇总
a i r p a k-建筑群流场模拟中边界条件的设定建筑群流场模拟中边界条件的设定摘要：CFD(Computational Fluid Dynamic)模拟技术近几年来随着计算机性能的大幅提高和模拟技术的进步，越来越得到广泛重视和应用。
边界条件的设定是直接关系到模拟成败的关键。
本文对边界设定中几个常见的问题分别进行了分析。
计算区域根据实际情况选取,水平方向参考取10倍最高建筑的高度，高度方向取3-4倍建筑物高度。
计算区域的顶面和侧面对于对称边界，速度边界和壁面这3种边界可以任意选择。
出流面可设为完全发展出流边界或速度边界。
对于大气层结中性情况，给出了风速廓线的计算公式，并介绍了一种为节约计算能力而分阶段划分网格的方法。
关键词：边界条件建筑外流场数值模拟1 引言风是构成室外环境的重要因素。
建筑群造成的流场变化会对其周围环境会产生一定的影响，特别是高层建筑更容易引起建筑周围行人高度局部风速的增大，产生不良的风环境，造成人的不适，降低环境质量。
如果在建筑规划设计阶段进行模拟研究，问题就可以得到预防和解决。
另外流场模拟对于结构风荷载以及自然通风等领域的研究也有价值。
风洞模型试验和实测是以往建筑流场研究的主要手段，但都费时费力。
CFD(Computational Fluid Dynamic)模拟技术近几年来随着计算机性能的大幅提高和模拟技术的进步，越来越得到重视和广泛应用，并取得了不少的成果。
作为有力的工具，数值模拟也已被用于建筑内外的流场研究中。
在模拟的过程中，除了湍流模型的选择，网格的划分等因素，边界条件也是直接关系到模拟成败的关键环节。
目前，数值模拟技术还处于发展阶段，只有不断与风洞试验和实测的结果进行比较，总结经验，对各方面进行改进，才能使之更加成熟完善。
本文结合模拟的例子，对边界设定中几个常见的问题分别进行了分析讨论。
2 模拟例子的情况简介本文通过结合一个模拟的例子来说明一些有关边界条件方面的问题。
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airpak常见问题问与答（一）建模基础1. My model is very complicated, what is the best way to buildit?2. How can I simplify my model?3. How often shall I save?4. I am making models with only small changes between them, shall I save them under different names or get different solutions under the same name?5. My area of interest is not surrounded by walls on all sides, is it OK to use the room walls or should I put openings on thesewalls?6. Should I include the effect of gravity in my model?7. Should I include the effect of radiation in my model?8. The calculation for the view-factor matrix is taking toolong, what is happening?9. How do I decide whether the flow is turbulent or laminar?10. Is is easier to import a model from a CAD package orconstruct the model inside Airpak?11. What are the CAD package files I can import into Airpak?12. What units should I use?13. How do I take the effect of elevation into account?14. My model is symmetric but my solution is not, what is thereason?15. What is a typical magnitude of flow velocity due to (pure)natural convection?16. Can I predict condensation in a room?--------------------------------------------------------------------------------My model is very complicated, what is the best way to build it ? Start simple. First include the most important items such as the cabinet, big power devices, fans, vents and openings, if any. For first level analysis, ignore small details. For example, you may smear power sources over blocks or plates, instead of modeling them in detail using small blocks. Make sure the simple model runs well and the solution makes sense. You can then gradually include more details into your model. It is absolutely essential that you build your model step by step!How can I simplify my model?To simplify your model, you may consider: reducing your model by using symmetry conditions using planar objects instead of thin objects breaking the model into two or more smaller modelsneglect small curves, small protrusions, etc.aligning nearly-aligned faces of objectsHow often shall I save?As with all software products, it is advisable to save as often as possible. This will ensure that your data is not lost in the event of machine or system failure. In particular, it is important to save the model before starting the solution process. So, if you need to terminate your solution process for any reason using the control C option, the latest model willbe saved.I am making models with only small changes between them, shall I save them under different names or get different solutionsunder the same name?If the changes are geometric (so that the mesh between the twois different) you should save them under different names. For example, if you have a model named job1, you may copy it to job2. Then make the changes you want in job2 and run it. However, if you are just changing the ventilation flowrate or inlet temperature (so that the mesh is the same), you may either save it to a different name, or, if you wish to use the Restart option, run a second solution under the same name.My area of interest is not surrounded by walls on all sides, is it OK to use the room walls or should I put openings on thesewalls?In general, it is not necessary to put openings on all room walls. It is sufficient to put openings on the walls which are perpedicular to the dominant flow direction(s). However, make sure that the walls that don't have openings are far enough so that they don't influence the flow distribution near the areaof interest.Should I include the effect of gravity in my model? Generally, you should include gravity because room air flows are relatively low velocity flows and the buoyant plumes from local heat sources or non-isothermal behavior of air jets canbe important to model. However, if you have an isothermal application, gravity will have no effect.Should I include the effect of radiation in my model? In most forced convection cases (where fluid is pushed through by fans, pumps, etc.), the effect of radiation is under 2-5% and may be ignored. In some cases, the effect may be of the order of 10% or even greater and must be included. Examples are:natural convection casessealed systemsisolated hot components radiating to nearby objects or theambientlarge areas radiating to the ambientsolar loadingIt is often a good practice to ignore the effect of radiation in the first level of analysis and include it later, in the finalstages of analysis.The calculation for the view-factor matrix is taking too long,what is happening?Your model probably has a large number of objects. Even if the number of objects participating in radiation is small, Airpakstill involves the other objects in the calculation. One way of speeding the calculation is to construct the radiation.ff file from a simpler Airpak model and use this file in the actual model. To construct the simpler model, make a copy of the actual model and delete some components that are either not participating in radiation or have minimal effect on radiation. Then compute the view factor matrix and use the resulting radiation file (radiation.ff) in the actual model. Another option is to activate the discrete ordinates radiation model which alleviates the need for a time-consuming view-factor calculation although the ensuing flow solution will require more computational time.How do I decide whether the flow is turbulent or laminar? Airpak estimates the non-dimensional numbers which will help you determine whether the flow is turbulent or laminar. For forced convection problems, the number to watch is the Reynolds number, for natural convection problems, look at the Rayleigh number. You can look at the estimates of these numbers by clicking the "Reset" button in Solution/Setup. The numbers as well as the recommended flow setting will be displayed in the messages window. In general, the flow is considered tubulentif the Reynolds number is greater than 5000 or the Rayleigh number if greater than 1e+8. The user is advised to use his/her own judgement as to this setting, particulary when the flow regime is in the transition region (between laminar andturbulent).Is is easier to import a model from a CAD package or constructthe model inside Airpak?It varies from case to case. In many cases, you can easily and rapidly construct your model in Airpak. In some cases, however, it may be advantageous to import from CAD packages directly. This is true in situations where transfering the dimensions (sizes and locations) is time consuming.What are the CAD package files I can import into Airpak? You can import an Airpak model from Pro/E directly. You can also import IGES files from any CAD package and DXF files fromAutoCad.What units should I use?You can use any system of units or a combination of them (e.g., SI, English system, etc.). You can define your units in the "Edit unit definitions" under "File/Configure". You can alsodefine units locally for any particular object (dimensions, properties, etc.). However, in general, it is advisable to use a consistent set of units so that the possibility of error isminimized.How do I take the effect of elevation into account?The effect of elevation can be taken into account by simply altering the density of air in the materials database. The default value of air density can be seen in "Model/Materials". Go to "Fluid/Gases/Air" and enter the new air density for the elevation under consideration. Make sure to click "Update"after editing the material properties.My model is symmetric but my solution is not, what is thereason?This is most likely due to one or both of the followingreasons:The mesh is not symmetric.The solution hasn't converged..What is a typical magnitude of flow velocity due to (pure)natural convection?It is of the order of 0.1 m/s.Can I predict condensation in a room?In Airpak, you can track water vapor as a species and look at the relative humidity. Although there is no condensation mass transfer model in Airpak, seeing results in which the relative humidity approaches 100% in some areas is a good indication that condensation is likely.。