流体引起的振动
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4. Starvation is the aerodynamic counterpart to cavitation. Like cavitation, it involves insufficient air flow
relative to fan capacity. Typical starvation spectra are almost identical to those of cavitation.
pulse, etc.).
气蚀会引起超声能量的上升，可用SKF加速度包络检测。
2020-03-04 ©SKF Slide 11 [Code] SKF [Organisation]
Cavitation Characteristics 气蚀特点
3. Cavitation will most often generate unique noise. Milder cavitation normally sounds like sand being
Flow-induced vibration includes each of the following:
• Hydraulic and Aerodynamic Forces • Cavitation and Starvation • Recirculation • Flow Turbulence • Surge • Choking
4. A great increase in blade pass vibration will be created if a pump impeller wear ring seizes to the shaft. 若泵口轮摩擦轴，会导致BPF频率振动的大幅上升；
5. Blade pass frequency in some particular fan types is particularly sensitive to damper settings. 对有些类型的风机，其叶片通过频率对阻尼设置情况非常敏感。
2020-03-04 ©SKF Slide 10 [Code] SKF [Organisation]
Cavitation Characteristics 气蚀特点
1. Classic spectra indicating cavitation have random, broad band energy most often between
harmonics coincide with natural frequencies of the rotor or support structure. Excessive vibration can result if allowed to do so.
需要尽力避免BPF及其倍频与转子或支撑结构的固有频 率临近，否则会引起较大的振动。
pumped whereas more severe cavitation will actually sound as if gravel is being passed through the pump.
气蚀通常会产生很奇特的现场噪声。中等程度的气蚀产生的 噪声象沙子在泵中流动，而严重的气蚀产生的噪声象小石子在泵中通 过。
2020-03-04 ©SKF Slide 6 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
3. A great increase in blade pass frequency will occur if welds securing diffuser vanes experience failure allowing the diffusers to shift position slightly relative to the impeller. 若导叶片的焊接处发生失效，使扩压器相对叶轮产生轻微位移，它会导致 BPF频率处的振动大幅上升；
气蚀是离心泵的常见问题，经常造成泵内部件的严重损坏。遭受连续 气蚀问题的泵叶轮会产生严重的点蚀，在一些案例中，气蚀会彻底蚕 食掉叶轮叶片。 在泵输送量过大或入口压力偏低条件下，泵容易产生气蚀。
2020-03-04 ©SKF Slide 9 [Code] SKF [Organisation]
Typical Spectrum of Cavitation & Starvation 典型的气蚀/抽空频谱
BRF = (RPM)(#Impeller Vanes)(#Diffuser Vanes)/K K = Highest Common Factor of #Impeller Vanes and #Diffuser Vanes
叶片比频率 (BRF)按下式计算： BRF = (转速)(叶轮叶片数)(导叶叶片数)/K
抽空与气蚀差不多一样，只不过它是风机的问题。典型的抽 空频谱与气蚀频谱几乎完全一样。
2020-03-04 ©SKF Slide 12 [Code] SKF [Organisation]
Recirculation 回流
In the case of a pump, recirculation is just the opposite of cavitation. Recirculation can occur when a pump is operated at too low a capacity or too high suction pressure.
其中：K＝叶轮叶片数和导叶叶片数的最大公约数 若两个叶片数不互质，则会产生较大的BRF频率的振动。
2020-03-04 ©SKF Slide 8 [Code] SKF [Organisation]
Cavitation and Starvation 气蚀与抽空
Cavitation is a common problem with centrifugal pumps and can be quite destructive to internal pump components. Often, pumps subjected to continuing cavitation will have badly pitted and/or eroded impellers. In some cases, cavitation can completely erode away impeller vanes. Cavitation most often occurs when a pump is operating with excess capacity or low suction pressure.
and stationary vanes coincide with one another. When they do coincide, there can be a pronounced pulse due to compression of the fluid (gas or liquid) between the rotating and stationary vanes.
Flow-Induced Vibration 流体引起的振动
2020-03-04 ©SKF Slide 1 [Code] SKF [Organisation]
Flow-Induced Vibration 流体引起的振动
Unlike many of the other mechanical vibration problems such as unbalance, misalignment, resonance and so forth, flow-induced vibration is often very dependent upon operating conditions. That is, it can be very affected by load depending on the type of machine and the work being performed by the machine.
流体引起的振动包括以下几种情况：
流体动力
气蚀和抽空
回流
紊流
喘振
2020-03-04 ©SKF Slide 3 [Code] SKF [Organisation]
流体堵塞
Hydraulic and Aerodynamic Forces 流体动力
Various types of machines including pumps, blowers, turbines, vacuum pumps and so forth inherently produce hydraulic or aerodynamic forces as their impellers impart work on the fluid (liquid or gaseous) they are handling. In general, hydraulic and aerodynamic forces are generated as per the following equation: Blade (or Vane) Pass Frequency = BPF = #Vanes X Impeller RPM (CPM or Hz)
be generated if an impeller is not centrally located within its housing and properly aligned with diffusers.
若叶轮在机壳中偏心或相对于蜗壳的位置不正确，会产 生较大的BPF及其倍频的振动。
2. It is important to ensure that neither the blade pass frequency nor blade pass
与不平衡、不对中和共振等许多问题不同，流体引起的振动往往与设 备的工艺运行状态密切相关。这就是说，依照设备类型的不同，设备 的负荷以及设备承担的工艺角色对振动的影响会很大。
2020-03-04 ©SKF Slide 2 [Code] SKF [Organisation]
Flow Relevant Faults 流体相关故障
Blade & Vane Pass Freq 叶片通过频率
2020-03-04 ©SKF Slide 5 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
1. Significant vibration both at blade pass frequency and blade pass harmonics will
2020-03-04 ©SKF Slide 7 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
6. Blade Rate Frequency (BRF) has to do with the number of times and rate at which rotating
很多类别的设备，包括泵、风机、透平机、真空泵等等，均会不可避 免地因为它们的叶片作用在输送的流体（液体或气体）上而产生流体 动力。 一般，流体动力的产生遵从下面的等式：
叶片通过频率 ＝ BPF ＝ 叶片数 x 叶轮转速 （cpm 或 Hz）
2020-03-04 ©SKF Slide 4 [Code] SKF [Organisation]
approximately 20,000 CPM up through approximately 120,000 CPM.百度文库
通常在300Hz至2,000Hz的频率范围内有随机宽带的振动。
2. When cavitation occurs it will increase ultrasonic measurements (spike energy, HFD, shock
relative to fan capacity. Typical starvation spectra are almost identical to those of cavitation.
pulse, etc.).
气蚀会引起超声能量的上升，可用SKF加速度包络检测。
2020-03-04 ©SKF Slide 11 [Code] SKF [Organisation]
Cavitation Characteristics 气蚀特点
3. Cavitation will most often generate unique noise. Milder cavitation normally sounds like sand being
Flow-induced vibration includes each of the following:
• Hydraulic and Aerodynamic Forces • Cavitation and Starvation • Recirculation • Flow Turbulence • Surge • Choking
4. A great increase in blade pass vibration will be created if a pump impeller wear ring seizes to the shaft. 若泵口轮摩擦轴，会导致BPF频率振动的大幅上升；
5. Blade pass frequency in some particular fan types is particularly sensitive to damper settings. 对有些类型的风机，其叶片通过频率对阻尼设置情况非常敏感。
2020-03-04 ©SKF Slide 10 [Code] SKF [Organisation]
Cavitation Characteristics 气蚀特点
1. Classic spectra indicating cavitation have random, broad band energy most often between
harmonics coincide with natural frequencies of the rotor or support structure. Excessive vibration can result if allowed to do so.
需要尽力避免BPF及其倍频与转子或支撑结构的固有频 率临近，否则会引起较大的振动。
pumped whereas more severe cavitation will actually sound as if gravel is being passed through the pump.
气蚀通常会产生很奇特的现场噪声。中等程度的气蚀产生的 噪声象沙子在泵中流动，而严重的气蚀产生的噪声象小石子在泵中通 过。
2020-03-04 ©SKF Slide 6 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
3. A great increase in blade pass frequency will occur if welds securing diffuser vanes experience failure allowing the diffusers to shift position slightly relative to the impeller. 若导叶片的焊接处发生失效，使扩压器相对叶轮产生轻微位移，它会导致 BPF频率处的振动大幅上升；
气蚀是离心泵的常见问题，经常造成泵内部件的严重损坏。遭受连续 气蚀问题的泵叶轮会产生严重的点蚀，在一些案例中，气蚀会彻底蚕 食掉叶轮叶片。 在泵输送量过大或入口压力偏低条件下，泵容易产生气蚀。
2020-03-04 ©SKF Slide 9 [Code] SKF [Organisation]
Typical Spectrum of Cavitation & Starvation 典型的气蚀/抽空频谱
BRF = (RPM)(#Impeller Vanes)(#Diffuser Vanes)/K K = Highest Common Factor of #Impeller Vanes and #Diffuser Vanes
叶片比频率 (BRF)按下式计算： BRF = (转速)(叶轮叶片数)(导叶叶片数)/K
抽空与气蚀差不多一样，只不过它是风机的问题。典型的抽 空频谱与气蚀频谱几乎完全一样。
2020-03-04 ©SKF Slide 12 [Code] SKF [Organisation]
Recirculation 回流
In the case of a pump, recirculation is just the opposite of cavitation. Recirculation can occur when a pump is operated at too low a capacity or too high suction pressure.
其中：K＝叶轮叶片数和导叶叶片数的最大公约数 若两个叶片数不互质，则会产生较大的BRF频率的振动。
2020-03-04 ©SKF Slide 8 [Code] SKF [Organisation]
Cavitation and Starvation 气蚀与抽空
Cavitation is a common problem with centrifugal pumps and can be quite destructive to internal pump components. Often, pumps subjected to continuing cavitation will have badly pitted and/or eroded impellers. In some cases, cavitation can completely erode away impeller vanes. Cavitation most often occurs when a pump is operating with excess capacity or low suction pressure.
and stationary vanes coincide with one another. When they do coincide, there can be a pronounced pulse due to compression of the fluid (gas or liquid) between the rotating and stationary vanes.
Flow-Induced Vibration 流体引起的振动
2020-03-04 ©SKF Slide 1 [Code] SKF [Organisation]
Flow-Induced Vibration 流体引起的振动
Unlike many of the other mechanical vibration problems such as unbalance, misalignment, resonance and so forth, flow-induced vibration is often very dependent upon operating conditions. That is, it can be very affected by load depending on the type of machine and the work being performed by the machine.
流体引起的振动包括以下几种情况：
流体动力
气蚀和抽空
回流
紊流
喘振
2020-03-04 ©SKF Slide 3 [Code] SKF [Organisation]
流体堵塞
Hydraulic and Aerodynamic Forces 流体动力
Various types of machines including pumps, blowers, turbines, vacuum pumps and so forth inherently produce hydraulic or aerodynamic forces as their impellers impart work on the fluid (liquid or gaseous) they are handling. In general, hydraulic and aerodynamic forces are generated as per the following equation: Blade (or Vane) Pass Frequency = BPF = #Vanes X Impeller RPM (CPM or Hz)
be generated if an impeller is not centrally located within its housing and properly aligned with diffusers.
若叶轮在机壳中偏心或相对于蜗壳的位置不正确，会产 生较大的BPF及其倍频的振动。
2. It is important to ensure that neither the blade pass frequency nor blade pass
与不平衡、不对中和共振等许多问题不同，流体引起的振动往往与设 备的工艺运行状态密切相关。这就是说，依照设备类型的不同，设备 的负荷以及设备承担的工艺角色对振动的影响会很大。
2020-03-04 ©SKF Slide 2 [Code] SKF [Organisation]
Flow Relevant Faults 流体相关故障
Blade & Vane Pass Freq 叶片通过频率
2020-03-04 ©SKF Slide 5 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
1. Significant vibration both at blade pass frequency and blade pass harmonics will
2020-03-04 ©SKF Slide 7 [Code] SKF [Organisation]
Hydraulic & aerodynamic force vibration 流体动力振动的特点
6. Blade Rate Frequency (BRF) has to do with the number of times and rate at which rotating
很多类别的设备，包括泵、风机、透平机、真空泵等等，均会不可避 免地因为它们的叶片作用在输送的流体（液体或气体）上而产生流体 动力。 一般，流体动力的产生遵从下面的等式：
叶片通过频率 ＝ BPF ＝ 叶片数 x 叶轮转速 （cpm 或 Hz）
2020-03-04 ©SKF Slide 4 [Code] SKF [Organisation]
approximately 20,000 CPM up through approximately 120,000 CPM.百度文库
通常在300Hz至2,000Hz的频率范围内有随机宽带的振动。
2. When cavitation occurs it will increase ultrasonic measurements (spike energy, HFD, shock