Investigation On Structures Of Lamilloy

With the development of gas turbine, the demanding of improving thermal efficiency and thrust-weight ratio results in the combustion chamber parts with high temperature and high heat capacity. The higher combustion chamber temperature demands more air to participate in combustion and less air to cool the flame tube wall; at the same time, the increasing temperature of compressor outlet makes the temperature of coolant air increasing which causes the power of coolant decreases. The current design methods for cooling structure can not meet the urgent demand of cooling for the future aircraft engine combustion.In this paper, numerical simulation is performed on the lamilloy plate and data is analyzed. The research contents as shown below: the distance and relative position of holes and pin-fins are simulated and analyzed to know the flow heat transfer characteristics of the lamilloy; the parameters of lamilloy such as geometry size, opening rate, cooling rate and blocking ratio are simulated to find out the influence of these parameters on the flow and heat transfer characteristics by comparative analysis. The results show that the lamilloy can obtain better effect on the flow and heat transfer characteristics when the relative position about hole and pin-fin is rhomboid arrangement; the increasing of impinging height makes the pressure drop decreasing and makes the discharge coefficient and comprehensive cooling efficiency increasing; the influence of opening ratio on the flow and heat transfer characteristics of lamilloy is not monotonous; the increasing of blocking ratio has little effect on the pressure drop and discharge coefficient, comprehensive cooling efficiency is the best when the blocking ratio is 8.7%; comprehensive cooling efficiency of lamilloy increases with increasing cooling ratio and decreasing of mainstream velocity.Experimental study is carried out on the typical lamilloy structures by using infrared thermal camera. The influence of comprehensive cooling efficiency with the changing of blowing ratio and hole ratio are analyzed. Results show that the wall temperature of lamilloy decreases with the increasing of blowing ratio. The change of blowing ratio has less effect on the wall temperature when the blowing ratio is bigger than 2.4; comprehensive cooling efficiency of the lamilloy with 2mm-film-hole is the best when the blowing ratio is 0.9. However, the comprehensive cooling efficiency of the lamilloy is best with 2mm-film-hole when the blowing ratio is 2.4.