Mitigating turbocharger bearing housing thermal loads: Experimental and numerical study for optimized heat shield inner rim sealing strategies

Elevated exhaust temperatures under high engine loads critically challenge turbocharger reliability. This study investigates the thermal insulation efficacy of turbocharger heat shields, focusing on the impact of inner rim gap configurations on bearing housing thermal loads. Through experimental and numerical analyses of five heat shield designs, ranging from closed inner rims to progressively enlarged gaps, we demonstrate that minimizing or eliminating the inner rim gap significantly reduces bearing housing temperatures. Key findings reveal maximum temperature reductions of 23.1 K near turbine-end sealing rings, 15.4 K at oil inlets, and 7.8 K at turbine-end floating bearings. Flow dynamics within the heat shield cavity, driven by rotational forces from the back disc gap and circumferential pressure non-uniformity in the volute, intensify convective heat transfer when gaps widen. Crucially, thermal load improvements remain consistent across varying turbine inlet temperatures ( TIT s) (873–1023 K) and expansion ratios ( ER s) (2.4–3.0). This work establishes design principles for heat shields that enhance reliability without costly cooling systems, offering practical solutions for cost-sensitive automotive applications.