Pumps are designed and manufactured to operate well away from the cavitation condition and thus the factors affecting the onset of cavitation are important. A specially designed test rig was and constructed so that the onset of cavitation could be studied visually while obtaining actual NPSH data. The magnitude of the NPSH level at 3% drop in total discharge head of a pump was determined at dif...

This paper concentrates on cavitation detection using discrete wavelet transform by classifying the pump vibration signal. Vibration signal acquired from centrifugal pump cavitation test rig carry more information about the cavitation classes. In this paper two classes has been defined namely, no cavitation class and developed cavitation class. This method uses the deviation from zero mean valu...

Cavitations inside hydraulic valves were investigated by using high-speed camera technology and noise spectrum analyzing method. The bubble flow’s morphological and flowing characteristics were converted into numerical information by the employment of image process, which made the two-phase flow easily identifiable. Based on this, cavitation’s distribution and shape characteristics were reveale...

Cavitation and turbulence in a diesel injector nozzle has a great effect on the development and primary breakup of spray. However, the mechanism of the cavitation flow inside the nozzle and its influence on spray characteristics have not been clearly known yet because of the internal nozzle flow complexities. In this paper, a comprehensive numerical simulation is carried out to study the intern...

influences of three prevalent mass transfer models, on modeling of cavitation, are investigated numerically. two models of singal and zwart are implemented in an open source code, open foam, while the kunz model is available for cavitation modeling. each model is used to flow simulation through a venturi. volume of gas fraction, in the specified sections of conduit, is compared to experimental ...

surface-piercing propellers (spps) have been widely used in high speed craft due to some desirable features such as high efficiency, omission of resistance of equipment attached to the propeller and proper functioning of cavitation. unlike the submerged propellers, theoretical methods have no significant application on simulation of sppsbecause of problems related to modeling of these propeller...

Propeller blade design for fast ships is often driven by cavitation constraints. A tradeoff exists, where larger chord lengths and section thicknesses typically improve cavitation performance but result in lower efficiency. Typically, chord lengths are optimized for the design condition (ship endurance speed), with some specified margin to prevent cavitation off-design (at maximum ship speed). ...

Multibubble effects on cavitation inception are studied in detail to show that bubble-bubble interaction can change the inception process of cavitation in a variety of ways. In an effort to develop a high-power pulsed neutron source which uses a giant proton accelerator and liquid mercury, we have attempted to use microbubbles to reduce cavitation damage of the mercury vessels caused by proton-...

To investigate a hypothesis of the orifice flow-induced instability in rocket engine thrust chambers, single liquid oxygen (LOX) injector with an optically accessible module was used for experiments, water as simulant LOX. The unsteady pressure downstream measured using high-speed piezoelectric sensors under cavitating and non-cavitating intra-injector flow conditions. flows were directly visua...