Unsteady simulation of cavitating turbulent flow for low head Francis turbine

29th IAHR Symposium on Hydraulic Machinery and Systems

Gohil, Pankaj P^1 ; Saini, R.P.^2

Mechanical Engineering Department, Sarvajanik College of Engineering and Technology, Surat, India^1

Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, India^2

关键词: Cavitation intensity;    Different operating conditions;    Mass transfer modeling;    Numerical predictions;    Off design condition;    Shear-stress transport;    Transient simulation;    Unsteady simulations;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/2/022007/pdf
DOI  :  10.1088/1755-1315/240/2/022007

来源: IOP

【 摘 要 】

Cavitation is undesirable phenomenon and it becomes more severe under off-design conditions and lower tail race level. Transient simulations has been performed using Shear Stress Transport (SST) turbulence model in CFX solver. The Rayleigh Plesset mass transfer model is applied for the numerical predictions of cavitating flow through Francis turbine. An attempt has been carried out to analysis of cavitating flow at low head Francis turbine under different operating conditions having varyingsuction heads. Summarizing, it has been found that the performance loss and cavitation rate are found maximum under over load conditions. A high amplitude of pressure at low frequency has been found at part load operating conditions of the turbine which may cause fatigue damage to the turbine over time. Cavitation intensity, performance loss and instability increase with increase of suction head.