Investigation Of Heat Transfer Characteristics Of Lamilloy

Lamilloy is considered as a promising cooling concept which can meet the high cooling effectiveness with low cooling air consumption. It has advantages of hot-side film cooling, internal impingement cooling and convective cooling, large internal heat transfer area and enhanced heat exchange caused by pin fin array.This paper is divided into two parts. Firstly, the state pressure, heat transfer coefficient and cooling effectiveness were investigated under different blowing ratios and Reynolds number based on the blade chord length. Secondly, conjugate numerical simulation studies on the heat transfer characteristics and fluid dynamics inside the cooling devices called lamilloy.In the experiment part, two turbo blades were made and tested in a heat transfer cascade. The pressure coefficients and velocity ratios distribution on the blade were measured on the smooth blade with Reynolds number changing from 100,000 to 300,000. The cooling characteristics investigation was also conducted with Reynolds number, blowing ratio varying from 100,000 to 250,000, from 0.5 to 2.0, respectively. The experiment results showed that:(l) the local heat transfer coefficients increased with the increasing of the Reynolds number and blowing ratios, the influence of blowing ratios was much higher on the pressure side as of the Reynolds number on the suction side. (2) the trend of the local heat transfer coefficients measured with cooling air was nearly the same with that without cooling air. (3) the outflow of cooling air enhanced the heat transfer on the pressure side while weakened it on the suction side at the low bowling ratios. (4) in the streamwise direction ,the cooling effectiveness increased quickly until it got to the highest 0.6 in the middle of the blade, then it decreased slowly.Coupled fluid/solid heat transfer calculation were performed to obtain the temperature distributions, the complex flow and heat transfer patterns in the laminate plate using the commercial codes FLUEN6.1. The numerical simulation reveals that the flow is complex in the specimen and the heat transfer is different on the plates, also the impingement of the coolant jets in the specimen is the main contribution to the high cooling effectiveness. The effects of blowing ratios and Reynolds number based on the impingement hole diameter on the cooling effectiveness of lamilloy wereanalyzed. Most of the heat transferred from hot gas to the Lamilloy was taken off by the coolant through the channel, which contributed to the high heat transfer rates on internal surface of outlet plate...