Reduction in Thomas Force of Rocket Turbopump Turbine by Using Robust Design Process

An application of robust design process for reduction in Thomas force of rocket turbopump turbines is presented in this paper. Because of its special specification, rocket turbopump turbines are designed as supersonic impulse turbines, and as a result, these blades have higher loading. In such a high loading blade, there is a possibility of rotor vibration problem generated by turbine instability force, that is, “Thomas Force”. Actually in the past engine development in Japan, there was the shaft vibration problem due to “Thomas Force”. In order to reduce shaft vibrations, it is important to keep “Thomas Force” small. In this paper, the results of parametric design for the existing rocket turbopump turbine by using the robust design process are discussed.