Effects of coolant mass flow rate ratio on heat transfer in a two-inlet rotating wedge-shaped channel

Abstract

Heat transfer characteristics of a novel turbine blade trailing edge internal cooling concept, two-inlet wedge-shaped channel with lateral fluid extraction, are experimentally investigated under both rotating and non-rotating conditions. In order to improve the heat transfer of the channel, a second coolant inlet is introduced in the vicinity of the low heat transfer region that previously observed in single-inlet configuration. The mass flow rate ratio (MR, second inlet mass flowrate/major inlet mass flow rate) ranges from 0 to 1. The major inlet Reynolds number and rotation number are varied from 6000 to 24,000 and 0 to 0.23, respectively. The results show that the second inlet coolant injection decreases local bulk temperature and increases local heat transfer at the high-radius half channel. In rotating cases, the second inlet notably improves the heat transfer at the top of the channel and compensates the negative effects induced by the rotation. The effect of the additional inlet is only significant in the vicinity of the coolant injection in both non-rotating and rotating cases. Moreover, with a MR of under 0.3, the second coolant injection benefits overall wall heat transfer at high rotation numbers.