| Turbine cooling technology plays a critical role in increasing the thermal efficiency and power output of advanced gas turbines. The common cooling methods include the impingement cooling method, the film cooling method, and the rib roughened cooling method. This study focuses on the impingement cooling effect on a rib roughened trailing edge channel with cross over holes and aims to find the influence of blocked exit holes to the heat transfer efficiency.;A steady state liquid crystal technique was used to get the heat transfer coefficient. In this experiment, two different kinds of cross over holes were used: five tilt angle and zero tilt angle. Both inline and staggered slot-arrangement were tested and investigated. There were total 16 geometry cases. The numbers of blocked exit holes are 0, 3, 4 and 5 for inline arrangement and 0, 2, 3 and 4 for staggered arrangement. For each geometry setting, a range of Reynolds numbers was tested. The graphs of the Nusselt number versus the Reynolds number were plotted. For each individual area, the Nusselt numbers with different number of blocked exit holes were compared. The results showed that the Nusselt numbers increase monotonically with increasing Reynolds numbers. It was also found that for staggered arrangement, the highest Nusselt numbers were found in the area two holes away from the nearest blocked exit hole. And for inline arrangement, conclusions are different between zero tilt angle and five tilt angle. With zero tilt angle, the Nusselt numbers of area1 and area2 both increased first and then decreased as the number of blocked holes increased. While with five tilt angle, Nusselt numbers of all the four areas decreased monotonically. |
