Experimental evaluation of internal air heat transfer capacity in large-scale centrifuges under low-pressure conditions

Abstract

The Centrifugal Hypergravity Interdisciplinary Experiment Facility (CHIEF) at Zhejiang University represents a significant advancement in centrifugal modeling, set to be the world’s fastest and largest hypergravity centrifuge to date. Large hypergravity centrifuges operate with enclosed, high-Reynolds-number rotating flows where aerodynamic power and air-side heat removal both depend on pressure. Lowering chamber pressure is a common strategy to curb windage losses, but it may also diminish the convective heat-transfer coefficient (CHTC) of air. Here we perform facility-scale, plate-based CHTC measurements in a concentric annular chamber representative of CHIEF, spanning 10–101 kPa and rotation up to 1000 g. We recast the correlation in a non-dimensional form, and validate it against measurements. Reducing pressure from 101 to 10 kPa lowers the air-side CHTC by ≈74% and the aerodynamic power by ≈81.5% at 1000 g, revealing a trade-off between power savings and heat-removal capacity. The proposed correlation reproduces the measured CHTC within ±10% across the tested pressure–rotation space, while straight-duct baselines (Dittus-Boelter/Gnielinski) systematically under-predict the rotating annulus. A 95% coverage analysis for CHTC and the cooling load (Q _air ) confirms the robustness of these trends. The wall-air temperature difference decreases non-linearly with pressure, consistent with the correlation. These results quantify how vacuum pumping reshapes internal heat dissipation and provide operational guidance for selecting pressure-rotation settings that balance heat production and air-side heat removal in large centrifuges.