Mechanism Research On Flow And Heat Transfer Of Film Cooling Induced By Different Coolant Chamber

Film cooling, as the representative of the advanced cooling technology, has been widely used in blade, end-wall, combustion chamber of gas turbine. The results show that kidney vortex is the main reason for coolant has been blown away by studying film cooling mechanism of flow and heat transfer. And many research jobs is developed to weaken or eliminate kidney vortex by modifying film-hole. But there is a little work about modified design of coolant chamber. Based on the plate film cooling, some novel coolant chamber have been studied in this paper, and which has been used on the end-wall of gas turbine to improve the film cooling effectiveness.According to the coolant flow structure in the film hole, the different ejection phenomena can produce different film cooling effectiveness, hence numerical investigation of different inlet angle is carried out. This paper is focus on the different jetting effect induced by different coolant chamber, the effect of flow structure and vortex system on film cooling effectiveness. Computational results show that kidney vortexes with inlet angle greater than 0 degrees is separated by the interaction between coolant and hot gas, the cooling effectiveness is better than that with original coolant chamber in high blowing ratio.In order to further destroy the kidney vortex, a new-type coolant chamber is presented in this paper which is named as swirling coolant chamber, whose mechanism is that the coolant jet from film-hole by unidirectional swirl. This paper is focus on the mechanism of eliminating kidney vortex by swirl coolant chamber, and the effect of vortex structure and inlet swirling strength on film cooling effectiveness. Computational results show that vortex structure with swirling coolant chamber is that one vortex oppress the other, hence the cooling effectiveness is evidently superior than that with original coolant chamber in high blowing ratio. The optimal blowing ratio is in the range of 1.8 to 2.1. The further investigation indicates that each research model corresponds to one best inlet swirling strength.Main flow orientation angle are everywhere in gas turbine. The effect of main flow with 15 degree orientation angle on film cooling characteristics of swirling coolant chamber is numerically studied in this paper. The research result shows that the swirling coolant chamber has the power to suppress the end-wall secondary flow. In this paper, the swirling coolant chamber has been used in the end-wall of gas turbine to obtain detailed flow field and temperature field. The research results shows that the film cooling effectiveness and cooled area with swirling coolant chamber is better than that of original coolant chamber, especially in high blowing ratio.