Heat transfer in a two-inlet rotating wedge-shaped channel with various locations of the second inlet

The heat transfer characteristics of a two-inlet wedge-shaped channel with lateral fluid extraction are experimentally investigated under both rotating and non-rotating conditions. Three different locations of the second inlet are tested. The effective inlet Reynolds number is fixed at 15,000 whereas the mass flow rate ratio (MR, second inlet mass flow rate/major inlet mass flow rate) ranges from 0 to 1.0. The highest rotation number is around 0.23. The results show that injecting the secondary coolant at the top of the channel should be the best option in the view of optimizing the bulk temperature and the heat transfer of the high-radius corner of the channel in both rotating and non-rotating cases. Two critical MR can be identified in the non-rotating channels. Higher the radius of the coolant injection, lower the critical MR. The magnitude of the second critical MR is double of the first one in all three cases. However, the local critical mass flow ratio (MR_x) is almost independent of the location of the second inlet. In both rotating and non-rotating cases, operating at high MR over the critical point is not recommended because the cooling air is not used efficiently. The influence of the second coolant injection is limited in the vicinity of the major inlet, which brings the convenience to optimize the local heat transfers without disturbing the heat transfer at the upstream locations.