Effect of jet flow on cooling performance and thermal stress of a radial turbine back disc

In view of the development status of high-reliability and low-cost cooling technology for radial turbine of micro-gas turbine or vehicle turbocharger, the impingement cooling technology of the radial turbine back disc was proposed, and the improvement of the cooling efficiency and thermal stress of the turbine back disc was numerically simulated. The results show that the impingement cooling technology can greatly improve the cooling efficiency of the turbine back disc and reduce the stress level. When the relative cooling flow is 1.0%–3.0%, the average cooling efficiency of the lower part of the turbine back disc is increased by 258%–486% compared with no cooling, which can reduce the thermal stress at the fillet of the back disc by 140–216 MPa. Both the average cooling efficiency and the fillet stress of the back disc increase slightly as the relative position of the jet hole moves outward. When the relative cooling flow is controlled within 2.0%, the effect of this cooling technology on the performance of the turbine can be ignored.