离心泵内部流动旋转失速特性研究

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vane inlet near the rim emerged a stable stall core,and spread谢tll the circumferential
direction toward the rotating impeller,which means stall core appeared in the vane diffuser.It suggested that the stall COre propagated along the circumference anti the
by
numerical simulation.The main work and contributions may he as follows:
pump 1.Two centrifugal
models equipped with single volute and radial diffuser
respectively have been established by Pro/E.Grid independence of the model Was
impeller rotating direction and its speed is about 20%of the impeller rotating speed.
By setting of pressure monitoring points,the low frequency pressure fluctuation was
Leabharlann Baidu
condition,and the migration effectively expanded the stable operation of safety region.
The double grooves on the vane can restrain the phenomenon of rotating stall effectively,but the head and efficiency will decrease respectively.From the comparison,the single groove has better head and the efficiency than double grooves. Therefore,specific#an should be determined in inhibit centrifugal pumps rotating
diffuser centrifugal pump happened.The reasons of the positive slope of the
in
离心泵内部流动旋转失速特性研究
performance Clll"ve were studied by the steady simulation tO the centrifugal pump
performance curve of diffuser centrifugal pump appeared the positive slope within 0.6Qd.0.7Qd,preliminary analysis of the reason was that the rotating stall in the
found at passages when the pump appears rotating stall.
pumps 4.Stating the method tO restrain the centrifugal
rotating stall with grooves.
Single groove on the vane call make the rotating stall move tO partial flow rate
mtemal turbulent flow field and related theory.It found that the pre—rotation of the
impeller inlet and rotating stall of centrifugal pump were the reasons of the positive
(Grant No.50979034).
pump's With the development of centrifugal
application in different discipline,
people begin tO concerning more about the safety when the centrifugal pump running·
systemic resonance of the pumP system,啪be produced in the pump's flow in
specific range,and they may bring unexpected influence tO the centrifugal pump.
During the process of running,sorts of unstable appearances,particularly when it is
working at partial load,would occur frequently.What makes the external
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江苏大学、中国科学技术信息研究所、国家图书馆、中国学术期刊(光盘版) 电子杂志社有权保留本人所送交学位论文的复印件和电子文档,可以采用影印、 缩印或其他复制手段保存论文。本人电子文档的内容和纸质论文的内容相一致, 允许论文被查阅和借阅,同时授权中国科学技术信息研究所将本论文编入《中国 学位论文全文数据库》并向社会提供查询,授权中国学术期刊(光盘版)电子杂 志社将本论文编入《中国优秀博硕士学位论文全文数据库》并向社会提供查询。 论文的公布(包括刊登)授权江苏大学研究生处办理。
taken out tO decide the number of the鲥ds tO make conclusion simulation results
more scientific and credible.
2.Employing the software Fluent,steady numerical simulation Was conducted on the two kinds of chambers at flow rates 0.2Qd·1.2Qd,the study found that the肝Q
本文采用数值模拟的方法对离心泵内旋转失速现象进行了研究。研究工作和 主要结论有:
1.运用Pm/E软件创建离心叶轮配置单蜗壳压水室和径向导叶压水室两种 离心泵模型。对离心泵进行网格数无关性检验,确定了较合理的网格数来使计算 结果更加科学和可信。
2.应用Fluent软件对两种压水室离心泵分别在0.2Qd.1.2Qd流量范围内进行 定常数值计算,研究发现导叶离心泵H-Q性能曲线在0.6Qd.0.7Q流量段出现了 正斜率,初步分析其原因为导叶离心泵内发生了旋转失速现象。通过定常模拟离 心泵模型内部湍流流场及相关理论,进一步探讨正斜率曲线出现的原因,认为正 斜率曲线是由于叶轮进口预旋及离心泵内旋转失速共同作用所致。
Science Foundation for Distinguished Young Scholars of China(Grant No.50825902) and‘‘Mechanism of Vibration and Noise Induced by htemal Unsteady Flow in Centrifugal Pumps’’supported by National Natural Science Foundation of China
摘要
本文系国家杰出青年基金项目“离心泵基础理论和节能关键技术研究”(编 号50825902)和国家自然科学基金项目“离心泵内部非定常流动诱导振动和噪 声机理"(编号:50979034)部分研究内容。
随着离心泵在多个领域的广泛应用,人们对其运行的安全性越来越重视。离 心泵在运行过程中,尤其在小流量工况下会产生很多不稳定现象。离心泵内旋转 失速现象的发生会使泵的外特性发生改变,产生正斜率。在发生失速的流量范围 内运行会产生振动和噪声,甚至导致系统的共振,严重影响离心泵性能。因此, 离心泵内旋转失速现象的研究在流体机械领域具有极其重要的意义。

江苏大学硕士学位论文
ABSTRACT
This paper is part of the projects“Research on the Basic Theory and
Energy-Saving Key Technology for Centrifugal Pumps’’supported by the National
slope of the performance culve. 3.Employing the unsteady simulation provided by software Fluent tO guide
diffuser centrifugal pump model.The study found that under the condition of 0.70d, backflow was found at the impeller and diffuser passage,and then vortices generated because of the reverse pressure gradient.When the flow rate decreased tO 0.6Qd,the
本学位论文属于不保密
学位论文作者签名:吾I l钗
3/o m 3-年石月f 6日
指导教师签名:
.驷t伊钒毛日
离心泵内部流动旋转失速特性研究
Research on the Characteristics on Rotating Stall in Centrifugal Pumps
姓 2012年6月
江苏大学硕士学位论文
4.提出了通过导叶开槽来抑制离心泵内旋转失速的方法。研究表明,导叶

离心泵内部流动旋转失速特性研究 单开槽可以使旋转失速的发生向小流量工况偏移,有效地扩大了离心泵稳定运行 的安全区间。导叶双开槽可以有效地抑制离心泵内旋转失速现象的发生,但其扬 程和效率都会相应地降低。通过比较可知,离心泵导叶单开槽时扬程和效率优于 导叶双开槽。因此在抑制离心泵内旋转失速时应根据工作需求来确定具体方案。 当需要较大的稳定运行区间时应损失部分效率而选用导叶双开槽方案,当其需要 的稳定运行区间较小而对效率要求较高时应选用导叶单开槽方案。 关键词:离心泵,旋转失速,正斜率曲线,压力脉动,数值模拟
pump characteristic of change is the rotating stall in centrifugal pumps,which c姐
lead tO positive slope.In the meantime,vibration and noise,which will generate
Therefore,the stall phenomenon call not be ignored in studying the fluid machinery,
and the analysis tO this phenomenon has great importance.
pumps The main topic of this paper is about the rotating stall in centrifugal
3.运用Fluent软件提供的非定常算法对径向导叶离心泵内部流动进行模拟。 研究发现,O.7Qd工况下导叶和叶轮流道内压力分布的不均匀使得导叶和叶轮流 场出现了旋涡,并且在叶轮进口出现回流现象。随着流量减小到0.6Qd工况时, 导叶进口靠近叶轮轮缘处出现了稳定的失速区,并随着圆周方向朝叶轮旋转相反 的方向传播,即导叶流道内出现了旋转失速现象。导叶进口及出口压力分布的不 均匀使得失速区沿着圆周方向传播,传播速度约为叶轮转速的20%。通过设置压 力监测点,发现离心泵出现旋转失速现象时,流道内部出现低频压力脉动。
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