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Experimental study of local temperature distributions in rotary blade couplings of four-wheel-drive vehicles with circumferentially ribbed turbulators

Abstract This work experimentally investigates temperature distributions of RBCs (rotating blade couplings) using circumferentially installed ribbed turbulators in real-time 4WD (four-wheel-drive) vehicles. Three types of circumferential rib turbulators are designed and installed in the RBC's inner rotating cylinder. These add to the area over which heat is transferred and prevent the generation of Taylor vorticity. A test rig is designed to make the key dimensionless parameters closely approximate the operating conditions of a real 4WD vehicle. The local temperature distributions in the axial and circumferential directions of a RBC with circumferentially ribbed turbulators, were measured and compared with those in smooth walls. Under the experimental conditions, the range of the rotational Reynolds numbers is 8.55≤ReΩ≤ 34.20. Results indicate the ribbed design with aspect ratio 2.5 (7.5 mm wide and 3 mm high) yields temperature distributions with the least variation that is the highest heat transfer among the three types of circumferential ribs. This study ultimately aims to find an effective design methodology that improves the temperature distribution of RBCs with circumferentially ribbed turbulators in a real-time 4WD vehicle. Finally, experimental results for circumferentially ribbed turbulators with three aspect ratios were empirically correlated.