14:00
Cavitation and cavitating flows I
Chair: Tom van Terwisga
14:00
30 mins
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RESEARCH ON THE EFFECTS OF SILT MEAN DIAMETERS AND SILT CONCENTRATIONS ON THE CAVITATION FLOW IN A TWO-DIMENSIONAL NOZZLE
Wweiguo Zhao, Xiangdong Han, Rennian Li, Ming Liu
Abstract: Effects of silt mean diameters and volume fractions are investigated in sediment laden cavitation flow in a two-dimensional nozzle. The silt mean diameters are 0.02mm, 0.04mm, 0.06mm, 0.07mm and 0.08mm and volume fractions are 2%, 4%, 6%, 7 % and 8%. When silt mean diameters are invariant, volume fractions are changed to take into account the effects of them and when volume fractions are the constants, silt mean diameters are varied to consider the effects of them. The results show that cavitation occurs at the beginning parts of the jet orifice and distributions of the vapor phase flow are axial symmetrical. Cavitation number variation with the volume fraction or with the silt mean diameter reflects the effect degree of silt particles towards the cavitation flow. With the silt mean diameters being 0.06mm, 0.07mm and 0.08mm, fluctuation of cavitation number with volume fraction is much larger than it with the silt mean diameters being 0.02mm and 0.04mm. During the volume fractions are fixed, all the fluctuations of cavitation number with silt mean diameters are vaster, demonstrating that silt mean diameters have an intense effect on cavitation flow. Reasons why silt particles promote the development of the cavitation are analyzed. Effect of the properties of silt particles, cavitation nucleons, pulsation of the pressure, instability of the boundary layer and virtual mass force are considered and studied.
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14:30
30 mins
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THE NUMERICAL SIMULATION OF PROPELLER CAVITATION IN NON-UNIFORM WAKE BASED ON OPENFOAM
CHAOSHENG ZHENG, LIWEI SHU, ZHIRONG ZHANG, DENGCHENG LIU
Abstract: In this paper, the numerical simulation results of the INSEAN E779A propeller cavitation are presented based on OpenFOAM. The present work is focused on the propeller cavitation in non-uniform wake. The present simulation is completed using RANS approach, VOF method and arbitrary mesh interface (AMI). Three different cavitation models, SchnerrSauer, Kunz and Merkle are adopted in the simulation. Furthermore, the effects of the cavitation models and the parameters on the cavition shape are investigated compared with experimental results. The key features, the cavitation shape change with the rotation angles, the collapse of the main cavitation and the roll up of the cavitation from the propeller surface into a leading edge vortex cavitation, show good agreement with the experiment observations.
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