Test and analysis model correlation - redesign of HTV's air ventilation system

The H-II Transfer Vehicle (HTV) is the Japanese spacecraft to transfer pressurized and unpressurized cargo to the International Space Station (ISS). For the HTV2 and the following flights, the cargo carrying capability of the PLC is improved from the HTV1 by changing the hardware layouts including the air ventilation system. In the system, both the number and location of diffusers were changed and return grills were eliminated. Computational Fluid Dynamics (CFD) case study was carried out to determine diffuser configuration, and it was found that the asymmetric angles between the remaining two diffusers created a large and stable vorticity in t he cabin, achieving high performance in compatibility rate of wind velocity. So, such a har dware layouts was adopted to the updated HTV design. This paper describes the flow pattern o bserved in the air flow measurement using the PLC cabin-simulated chamber reflecting the detail updated design of the HTV. This paper also discusses the CFD analysis result b ased on measurement configuration which corresponds to the measurement result well. It was confirmed that the hardware layouts creates a large vorticity in the cabin effectively and the CFD model was correlated with measured data.