Design of an Air-Starter Turbine and Starting Performance Prediction Through the Numerical Analysis

To get the required power, a procedure for starting an engine is required For an engine of the large ship or land based power plant, two kinds of mechanisms exist: one is to use an electric motor and the other air-starter. As one of the starting methods of heavy-duty engines, the air-starter gives rotating power from the blade ling force by the compressed air flow through the turbine to rotate the stopped engine. Since the air turbine has a large weight-to-power ratio, simple structure and is spark-free, many heavy-duty engine are equipped with this device for their starting process. In order to get high enough power required to rotate the engine up to sufficient speed in a short time, high instantaneous torque is required. An impulsive supersonic turbine can be applied for this purpose. In this case, an one-stage air turbine with a minimum length convergent-divergent nozzle and transition arc shaped rotor was utilized to reduce shock loss. The performance of the desired turbine is evaluated numerically and compared with experimental results. The spin-down test is performed to estimate the performance of the designed turbine and numerical analysis is performed using the commercial tool ANSYS CFX.