Aero‐design of transonic LH2 and LOX contra rotating turbopumps in an expander rocket engine

Abstract

Purpose

Contra‐rotating turbines offer reduced size, weight, and cooling requirements, compared to conventional co‐rotating machinery. In spite of the associated mechanical complexity, their aero‐thermal performance is superior to conventional turbines, not only due to the elimination of stator blade rows, but also because lower turning airfoils can be implemented as a result. The purpose of this paper is to present a methodology to determine the optimum velocity triangles of the turbine, together with a two‐dimensional design and optimization tool to minimize the blade unsteady force using radial basis function network, coupled to a genetic algorithm. The proposed design methodology is illustrated with the aerodynamic design of a contra‐rotating two‐axis turbine, which is able to deliver the power necessary to drive the LOX and LH2 pumps of an improved expander rocket engine.

Design/methodology/approach

This paper presents a methodology to determine the optimum velocity triangles of the turbine, together with a two dimensional design and optimization tool to minimize the blade unsteady force using radial basis function network, coupled to a genetic algorithm. The proposed design methodology is illustrated with the aerodynamic design of a contra‐rotating two‐axis turbine, which is able to deliver the power necessary to drive the LOX and LH2 pumps of an expander rocket engine, namely the Japanese LE‐5B.

Findings

The airfoil optimizer allows reductions in the downstream pressure distortion of 40 per cent. Consequently, the unsteady forces in the downstream blade row are minimized.

Originality/value

This paper presents to turbomachinery designers in liquid propulsion a novel tool to enhance the aerodynamic performance while reducing the unsteady forces on the blades.

Citation

Paniagua, G., Lavagnoli, S., Verstraete, T., Mahmoudi, W. and Benamara, T. (2013), "Aero‐design of transonic LH2 and LOX contra rotating turbopumps in an expander rocket engine", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 23 No. 4, pp. 575-587. https://doi.org/10.1108/09615531311323746