The Correction and Evaluation of Cavitation Model considering the Thermodynamic Effect

Abstract

Two cavitation models with thermodynamic effects were established based on the Rayleigh-Plesset equation to predict accurately the cavitation characteristics in the high-temperature fluid. The evaporation and the condensation coefficient of the cavitation model were corrected. The cavitation flow of NACA0015 airfoil was calculated using the modified cavitation model, where the influence of the thermodynamic effects of airfoil cavitation was analyzed. The result showed that the pressure coefficient distribution and the bubble volume fraction simulated have the same tendency of Zwart-Gerber-Belamri model's result. According to the experimental data, the two models provide more accurate results. At the room temperature, the values of d V /d obtained by the two improved models are approximately equal. The difference between the two models' results increases gradually with the temperature increasing, but it is still small. The simulation results are consistent with the experimental data when the evaporation coefficient is 10 and 1. When the evaporation coefficient is 1, the bubble growth is inhibited, the volume fraction becomes lower, and the cavitation area becomes flat. As the temperature increases, the cavitation area and the bubble volume fraction at airfoil front edge become larger, showing that the temperature plays a "catalytic" role in the cavitation process.

Investigation of the cavitation performance in an engine cooling water pump at different temperature

“…However, the cavitation damage becomes severe while increasing the rotating speed, so the rotating speed should be limited. 28 The Q-H curve of the engine cooling water pump at 2960 r/min and 4300 r/min are converted to the curves at 3700 r/min according to the similarity conversion law which is shown as equations ( 1) and (2). Comparing the result from similarity conversion and the experiment result, it is fund that the error of head is below 5%, which indicates that the similarity conversion law is applicative for engine cooling water pump.…”

“…1 Its performance not only affects the car engine performance, economy, but also related to the life of the machine. [2][3][4][5] As the working temperature of engine cooling water pump is high (75-85 C), the speed range is large (2000$5000 r/min) and the structure size is limited, the flow field at the inlet and outlet of cooling water pump is much complicated compared with common water pumps, which increases the hydraulic loss and decreases the efficiency greatly. [6][7][8][9][10] At the same time, under the conditions of high temperature, high speed and large flow rate, the cavitation phenomenon of engine cooling water pump is more likely to occur.…”

Numerical Simulation of Cavitation Performance in Engine Cooling Water Pump Based on a Corrected Cavitation Model

“…The current cavitation models based on transport equation (Transport Equation Model, TEM) including Zwart-Gerber-Belamri model, Singhal full-cavitation model, Schnerr-Sauer model, Kunz and Merkle model, are used to simulate phase transformation between vapor and liquid. In this research, Zwart model was modified based on R-P thermal equation [26], condensation source term (m + ) and evaporation source term (m − ) are as follows:…”

Novel Affordable, Reliable and Efficient Technologies to Help Addressing the Water-Energy-Food Nexus

“…However, cavitation regimes are subtly modulated by several details, such as the reactor's geometry (Carpenter, Badve, et al, 2017;Šarc et al, 2017), the flow rate and the inlet pressure, the geometry and the mechanical power of the impellers (Carpenter, Badve, et al, 2017;Pawar et al, 2017), as well as the content in dissolved gases and solid particles (Patil & Pandit, 2007). The medium temperature also plays an important role, with a peak in cavitation aggressiveness around 60°C (Dular, 2016;Li, Yang, Shi, Zhao, & Li, 2018). Cavitation processes concentrate the energy of the bulk liquid medium, up to extremely high local density, into a myriad of microscopic hot spots, located at the collapse of the bubbles (Pawar et al, 2017;Yasui et al, 2004).…”