Investigation on the Effect of Impingement Chamber Structure and Cooling Unit Number on Composite Cooling

In order to deeply explore the influence and mechanism of the impingement chamber structure and the number of cooling units on the film cooling performance. Based on the Realizable k-ε turbulence model with finite volume composite cooling structure as the research object, the cold flow in the cooling structure with different volumes and shapes of impingement chambers and different numbers of cooling units is investigated in this paper. The numerical method is verified by the existing experimental results, and the grid independence analysis is carried out. The changes of flow field structure and cooling effectiveness under different working conditions are comprehensively analyzed. The results indicate that the volume and shape of the impingement chamber influence the flow structure of the cold flow in the chamber, thereby affecting the flow state of the cold flow in the film hole, ultimately resulting in different momentum distributions of the cold flow at the outlet of the film hole. The strength of the kidney-shaped vortex pair on both sides of the film is directly affected by the momentum distribution of the cold flow at this location, leading to the difference in the film cooling flow on the wall. It is found that the composite cooling structure with a volume of 0.8Vr and a circle impingement chamber has better cooling flow ductility and wall adhesion. The momentum distribution of the film hole outlet section of the increased cooling unit is affected by the film flow with regarding the impingement hole, impingement chamber and film hole as a single cooling unit, and the surface-averaged film cooling effectiveness at Nu=4 is improved by approximately 78.47% compared to Nu=1.