流體引起的振動ppt課件-wenkub
2023-05-16 06:33:41 本頁面
【正文】 icant vibration both at blade pass frequency and blade pass harmonics will be generated if an impeller is not centrally located within its housing and properly aligned with diffusers. 若葉輪在機殼中偏心或相對于蝸殼的位置不正確，會產(chǎn)生較大的 BPF及其倍頻的振動。 一般，流體動力的產(chǎn)生遵從下面的等式： 葉片通過頻率 ＝ BPF ＝ 葉片數(shù) x 葉輪轉(zhuǎn)速 （ cpm 或 Hz） 20220529 169。這就是說，依照設(shè)備類型的不同，設(shè)備的負荷以及設(shè)備承擔(dān)的工藝角色對振動的影響會很大。20220529 169。 20220529 169。SKF Slide 5 [Code] SKF [Organisation] Blade amp。 2. It is important to ensure that neither the blade pass frequency nor blade pass harmonics coincide with natural frequencies of the rotor or support structure. Excessive vibration can result if allowed to do so. 需要盡力避免 BPF及其倍頻與轉(zhuǎn)子或支撐結(jié)構(gòu)的固有頻率臨近，否則會引起較大的振動。 20220529 169。SKF Slide 9 [Code] SKF [Organisation] Cavitation and Starvation 氣蝕與抽空 Cavitation is a mon problem with centrifugal pumps and can be quite destructive to internal pump ponents. Often, pumps subjected to continuing cavitation will have badly pitted and/or eroded impellers. In some cases, cavitation can pletely erode away impeller vanes. Cavitation most often occurs when a pump is operating with excess capacity or low suction pressure. 氣蝕是離心泵的常見問題，經(jīng)常造成泵內(nèi)部件的嚴(yán)重損壞。SKF Slide 10 [Code] SKF [Organisation] Typical Spectrum of Cavitation amp。 20220529 169。典型的抽空頻譜與氣蝕頻譜幾乎完全一樣。 When it occurs, a portion of the fluid returns from the discharge to the impeller as the pump attempts to move an excessive amount of fluid through the pump. This brings about a reverse flow and results in 2 or more fluids moving in opposite directions causing noise and vibration. 回流發(fā)生時，一部分流體會從出口回流到葉輪中，因為泵實際上在輸送過多的流體。SKF Slide 14 [Code] SKF [Organisation] Recirculation Characteristics 回流特點 1. Recirculation generates vibration spectra very similar to those caused by cavitation. That is, it will often have random, higher frequency vibration, sometimes superimposed with vane pass frequencies. 回流頻譜與氣蝕頻譜非常相似，也有隨機寬帶振動，有時還有葉片通過頻率。SKF Slide 15 [Code] SKF [Organisation] Flow Turbulence 紊流 Flow turbule
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