Cavitation In Centrifugal Pump Research Articles

Numerical Simulation of Cavitation in a Centrifugal Pump at Low Flow Rate

Based on the full cavitation model which adopts homogeneous flow supposition and considering the compressibility effect on cavitation flow to modify the re-normalization group k-∊ turbulence model by the density function, a computational model is developed to simulate cavitation flow of a centrifugal pump at low flow rate. The Navier-Stokes equation is solved with the SIMPLEC algorithm. The calculated curves of net positive suction head available (NPSHa) HNPSHa agree well with the experimental data. The critical point of cavitation in centrifugal pump can be predicted precisely, and the NPSH critical values derived from simulation are consistent with the experimental data. Thus the veracity and reliability of this computational model are verified. Based on the result of numerical simulation, the distribution of vapor volume fraction in the impeller and pressure at the impeller inlet are analyzed. Cavities first appear on the suction side of the blade head near the front shroud. A large number of cavities block the impeller channels, which leads to the sudden drop of head at the cavitation critical point. With the reduction of NPSHa, the distribution of pressure at the impeller inlet is more uniform.

Novel method for detecting cavitation in centrifugal pump with frequency converter

Novel method for detecting cavitation in centrifugal pump with frequency converter

Estimating uncertainty of measurements for cavitation detection in a centrifugal pump

Measurement of noise and vibration signal in audible frequency range to detect cavitation in centrifugal pumps is rather unknown technique. There were already some studies performed on this technique and they showed quite good results. Due to many factors that influence the quality of the measurement, an uncertainty analysis should be performed. This paper deals with estimation of a measurement uncertainty for different kinds of measurement ways to detect the cavitation in a centrifugal pump with noise and vibration signal in audible frequency range from 20 Hz to 20 kHz. Especially the measurement uncertainties for cavitation detection in broad frequency range and at a discrete frequency were analyzed. Results showed that this technique is reliable despite many possible influences on uncertainty.

Characterization of Sealing Ring Cavitation in Centrifugal Pumps with Water and Viscous Oil

Characterization of Sealing Ring Cavitation in Centrifugal Pumps with Water and Viscous Oil

925 遠心羽根車に生じるキャビテーションの理論解析

This paper discribes about theoritical analyses of cavitation in centrifugal pump. A linear stability analysis is carried out by using the singularity method based on a closed cavity model allowing the cavity length freely to change. For 4 bladed impeller, a mode corresponding to the transition to alternate blade cavitation was examined. For 5 bladed impeller, various kind of rotating cavitation was found.

Application of spectral analysis techniques to cavitation in centrifugal pumps

ABSTRACT An experimental investigation has been performed to study the inception of cavitation and the effect of entrained air on cavitation in a double suction centrifugal pump. Experiments have been organized to cover off-design flow rates and reduced suction pressures independently so that has been possible to study both the effect of flow rate and suction pressure. Air of known amounts has been entrained from the suction pipe to investigate its effect on the intensity of cavitation and the performance of the pump. Pressure transducers and a FM tape recorder have been used to record the pressure signals acquired from three locations on the set-up. Consequently the data has been digitized and processed by spectral analysis techniques. The power spectra and the RMS values of the pressure signals have been investigated to reveal the inception and extend of cavitation as well as the effect of entrained air. As a result of the study carried out, it has been possible to conclude that spectral analysis techniques are useful tools for the detection of the inception and extend of cavitation and that although having some cushioning effect at the suction side of the pump air entrainment is not an effective method in reducing cavitation damage.

231. The effects of fluid properties on cavitation in centrifugal pumps: W A Spraker,J Eng Power, 87(3), 1965, 309–318

231. The effects of fluid properties on cavitation in centrifugal pumps: W A Spraker,J Eng Power, 87(3), 1965, 309–318

The Effects of Fluid Properties on Cavitation in Centrifugal Pumps

An analytical model of the cavitation process in a pump is developed assuming that the flow is adiabatic, frictionless, steady, and irrotational. A relationship is developed relating the volume percentage of the fluid vaporized during the cavitation process to the “thermal cavitation parameter.” Two assumptions are then introduced concerning the cavitation process in a pump pumping fluids of different cavitation characteristics. Using these assumptions, a relationship is derived indicating that the difference in net positive suction head (NPSH) of a given pump handling two fluids is a function of the difference of the reciprocals of the thermal cavitation parameter for the two fluids and of the volume percentage of the fluid vaporized. This relationship is compared with data describing the cavitation characteristics of six pumps handling four pure fluids. The change in NPSH for all of the pumps and fluids, using the cold-water NPSH as a reference, is found to correlate as a function of the reciprocal of the thermal cavitation parameter with an accuracy of ±1 ft in NPSH. Experimental and analytical methods for determining the cavitation characteristics of pumps handling petroleum-based hydrocarbon mixtures are then described. Cavitation data for two pumps handling gasoline, fuel oil, and crude oil are presented. The data correlation for pure fluids is extended to include cavitation data for petroleum-based hydrocarbon mixtures. It is found that mixtures exhibit an additional decrement in NPSH over that for pure fluids having the same value of the thermal cavitation parameter. This additional decrement is found to be temperature dependent.

Closure to “Discussions of ‘Cavitation in Centrifugal Pumps With Liquids Other Than Water’” (1961, ASME J. Eng. Power, 83, p. 89)

Closure to “Discussions of ‘Cavitation in Centrifugal Pumps With Liquids Other Than Water’” (1961, ASME J. Eng. Power, 83, p. 89)

Cavitation in Centrifugal Pumps With Liquids Other Than Water

Conditions leading to cavitation of liquids other than water are examined. The concept of the thermal cavitation criterion is considered in view of new test data on hot water and other liquids, and its utility for determination of NPSH corrections is demonstrated. The effect of the suction specific speed on the NPSH corrections is tentatively established.

うず巻ポンプのキャビテーションに及ぼす羽根車羽根入口先端の形状の影響

うず巻ポンプのキャビテーションに及ぼす羽根車羽根入口先端の形状の影響

On the mechanism of cavitation in centrifugal pumps. (in Russian) : V. F. Chebaevskii. Teploenergetika, v. 4, no. 9, Sept. 1957, p. 12–16

Most of the current successes of deep transfer learning-based fault diagnosis require two assumptions: 1) the health state set of source machines should overlap that of target machines; 2) the number of target machine samples is balanced across health states. However, such assumptions are unrealistic in engineering scenarios, where target machines suffer from fault types that are not seen in source machines and the target machines are mostly in a healthy state with only occasional faults. As a result, the diagnostic knowledge from source machines may not cover all fault types of target machines nor address imbalanced target samples. Therefore, we propose a framework, called a multi-source transfer learning network (MSTLN), to aggregate and transfer diagnostic knowledge from multiple source machines by combining multiple partial distribution adaptation sub-networks (PDA-Subnets) and a multi-source diagnostic knowledge fusion module. The former weights target samples by counter-balancing factors to jointly adapt partial distributions of source and target pairs, and the latter releases negative effects due to discrepancy among multiple source machines and further fuses diagnostic decisions output from multiple PDA-Subnets. Two case studies demonstrate that MSTLN can reduce the misdiagnosis rate and obtain better transfer performance for imbalanced target samples than other conventional methods.