Dr. Hideyo Negishi presented “Numerical Analysis of Unshrouded Impeller Flowfield in the LE-X Liquid Hydrogen Pump” at the 2017 Joint Propulsion Conference. CRUNCH CFD was used by JAXA to perform the 3D, unsteady RANS simulation of the pump.
The unshrouded impeller applicable to liquid rocket pumps is a new technology compared to the conventional shrouded impeller widely used in existing liquid rocket engines. Although many past studies have investigated head/suction performance, the rotordynamic and axial forces acting on an unshrouded impeller, the detailed flow field in unshrouded impellers, and particularly the influence of the compressibility of hydrogen have yet to be discussed. This paper describes the application of three-dimensional and unsteady Reynolds-averaged Navier-Stokes simulations to investigate the detailed flow field in a liquid rocket hydrogen pump with an unshrouded impeller. In order to investigate the influence of the compressibility of hydrogen, both compressible and incompressible URANS simulations were performed for comparison with the LE-X hydrogen pump test. First, the computed results were validated relative to the experimental results obtained in the pump test. Second, the detailed flow field was investigated by comparing the compressible and incompressible URANS results. The computed results agreed well with the experimental results, and revealed several key features in the unshrouded impeller.
Hideyo Negishi, Shinji Ohno, Yohei Ogawa, Kenji Aoki, Teiu Kobayashi, Koichi Okita, and Tsutomu Mizuno. Numerical Analysis of Unshrouded Impeller Flowfield in the LE-X Liquid Hydrogen Pump, 53rd AIAA/SAE/ASEE Joint Propulsion Conference, AIAA Propulsion and Energy Forum, (AIAA 2017-4930)