Investigation on effects of impingement jets on heat transfer characteristics of internal cooling passage side wall

A simplified enlarged model of the trapezoidal internal cooling passage near the leading edge is built up. An experimental research based on the inclined impingement cooling in the passage is conducted to understand the heat transfer characteristics on the internal wall. The data of the heat transfer is analyzed combining with the flow fields data, which is helpful to understand the heat transfer mechanism inside such kind of confined channel as well as provide some useful information for the design of a more effective internal cooling structure. The temperature on the side exit wall was measured by the thermocouples. The effects of the impingement angle, the cross flow and the impingement Reynolds number on the Nusselt number of the side wall were considered. Important results of the research include: the suction effect of the side exit hole enhances the heat transfer of the side wall near the hole edge. The increase of the impingement angle makes the peak of Nu become sensitive to the variation of the impingement angle. The cross flow decreases Nu on the side wall and has different effects on the different region of the side wall. The increase of the impingement Reynolds number improves the heat transfer ability evidently on the entire side wall, when it does not change the heat transfer characteristics on the side wall.