Conjugated heat transfer simulation of flow mechanism and heat transfer characteristic of sweeping jet impinging on leading edge in turbine cascade

Abstract

Increasing inlet temperatures of gas turbines is the way to go for the development of advanced aero engines. As the inlet gas temperature of modern gas turbine engines continues to increase, the operating temperature has far exceeded the melting temperature of the typical heated region. Excessive temperatures can cause turbine blade ablation and damage, thus affecting the reliability and safety of the engine. The sweeping jet actuator (SJA) is a fluid oscillator that has attracted considerable attention in the field of enhanced heat transfer and flow control due to its non-constant sweeping characteristics. As a new impinging cooling method, this paper adopts the device to carry out the research work on the flow mechanism and heat transfer characteristics of sweeping jet (SJ) impinging on leading edge in gas turbine blade. Firstly, the numerical investigation of conjugated heat transfer simulation combined with unsteady Reynolds-averaged Navier–Stokes (URANS) is conducted to analyze the cooling performance of SJ. Using a C3X high-pressure turbine blade as a prototype, the temperature drop with the SJ scheme was improved by 1.8 K and 8.7 K compared with the circle jet (CJ) scheme for H/D = 1 and H/D = 5, respectively. Finally, the internal flow field of the blade is reconstructed by combining the proper orthogonal decomposition (POD) method. Through the POD method, we can deeply analyze the mechanism of the effect of SJ on the non-constant heat transfer at the leading edge of the blade, which provides theoretical support for the practical engineering application of SJ in the future industrial field.