Numerical Investigation to Gas Turbine Performance of Underwater Vehicle

A three-dimensional, viscous, steady computational fluid dynamics(CFD) analysis is performed for investigating gas turbine flow field and performance of underwater vehicle by solving RANS-Navier-Stocks equations and RNG- turbulence model. The flow detail and losses of the turbine are studied in designing and off-designing conditions. The effect factor on turbine efficiency is analyzed. The results show that the flow characteristics of nozzle are independent of turbine blade flow. When pressure ratio is less than a critical value, the performance of turbine degrades rapidly as pressure ratio decreases. The turbine efficiency gets the maximum at another critical pressure ratio, and descends fast with pressure ratio decreasing when pressure ratio is less than the critical value.The turbine efficiency also descends as rotational speed decreases.