流體引起的振動(dòng)ppt課件(更新版)
【正文】 Cavitation Characteristics 氣蝕特點(diǎn) 1. Classic spectra indicating cavitation have random, broad band energy most often between approximately 20,000 CPM up through approximately 120,000 CPM. 通常在 300Hz至 2,000Hz的頻率范圍內(nèi)有隨機(jī)寬帶的振動(dòng)。 aerodynamic force vibration 流體動(dòng)力振動(dòng)的特點(diǎn) 6. Blade Rate Frequency (BRF) has to do with the number of times and rate at which rotating and stationary vanes coincide with one another. When they do coincide, there can be a pronounced pulse due to pression of the fluid (gas or liquid) between the rotating and stationary vanes. BRF = (RPM)(Impeller Vanes)(Diffuser Vanes)/K K = Highest Common Factor of Impeller Vanes and Diffuser Vanes 葉片比頻率 (BRF)按下式計(jì)算： BRF = (轉(zhuǎn)速 )(葉輪葉片數(shù) )(導(dǎo)葉葉片數(shù) )/K 其中： K＝ 葉輪葉片數(shù)和導(dǎo)葉葉片數(shù)的最大公約數(shù) 若兩個(gè)葉片數(shù)不互質(zhì)，則會(huì)產(chǎn)生較大的 BRF頻率的振動(dòng)。SKF Slide 6 [Code] SKF [Organisation] Hydraulic amp。SKF Slide 2 [Code] SKF [Organisation] FlowInduced Vibration 流體引起的振動(dòng) Unlike many of the other mechanical vibration problems such as unbalance, misalignment, resonance and so forth, flowinduced 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. 與不平衡、不對(duì)中和共振等許多問(wèn)題不同，流體引起的振動(dòng)往往與設(shè)備的工藝運(yùn)行狀態(tài)密切相關(guān)。SKF Slide 3 [Code] SKF [Organisation] Flow Relevant Faults 流體相關(guān)故障 Flowinduced vibration includes each of the following: ? Hydraulic and Aerodynamic Forces ? Cavitation and Starvation ? Recirculation ? Flow Turbulence ? Surge ? Choking 流體引起的振動(dòng)包括以下幾種情況： 流體動(dòng)力 氣蝕和抽空 回流 紊流 喘振 流體堵塞 20220529 169。 20220529 169。遭受連續(xù)氣蝕問(wèn)題的泵葉輪會(huì)產(chǎn)生嚴(yán)重的點(diǎn)蝕，在一些案例中，氣蝕會(huì)徹底蠶食掉葉輪葉片。SKF Slide 12 [Code] SKF [Organisation] Cavitation Characteristics 氣蝕特點(diǎn) 3. Cavitation will most often generate unique noise. Milder cavitation normally sounds like sand being pumped whereas more severe cavitation will actually sound as if gravel is being passed through the pump. 氣蝕通常會(huì)產(chǎn)生很奇特的現(xiàn)場(chǎng)噪聲。這樣會(huì)引起反向的液流。紊流可能是管道中的障礙物、直角彎角以及急劇的直徑改變等引起的。發(fā)生喘振問(wèn)題的壓縮機(jī)通常是工作在設(shè)計(jì)范圍以外。葉片通過(guò)頻率幅值會(huì)上升一倍或者甚至兩倍。
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