Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 07, 2019 - November 08, 2019
Turbine stages for rocket engine usually operate in a supersonic regime, causing some serious troubles in turbine efficiency and vibration. Therefore, highly efficient and reliable turbines driven with a small amount of mass flow rate are strongly required. In addition, it is important to reduce manufacturing costs. This study accordingly have dealt with numerical investigation on scarfed nozzle, which is composed of axisymmetric and non-axisymmetric parts and relatively easy to manufacture as a supersonic turbine nozzle for rocket engine, calculating its aerodynamic performance in comparison with conventional turbine nozzles. Six test cases are examined, where three types of first stage nozzles, that is conventonial turbine nozzle and two scarfed nozzles, are used along with two sets of the first stage turbine blade and second stage turbine vanes and blades. As for computational grid used in the three-dimensional steady simulation, wall function treatment is applied to the flow field near the solid wall to reduce the computational cost. According to the numerical results, due to first rotor load ratio, clear differences are observed in turbine efficiency among the test cases, which can be attributed to loading balance between the first and second stages. Also, turbine efficiency using scarfed nozzle is improved by 0.3% through the decrement in the design outlet Mach number at the exit of the axisymmetric part of the scarfed nozzle.
