Impingement Heat Transfer In The Leading Edge Cavity Of A Gas Turbine Vane

Jet Impingement Cooling is an internal cooling technique used in the leading edge cavities of Turbine Vanes. This involves a series of jets impinging onto the internal surfaces of a turbine vane/blade through the impingement plate. For the model tested here, the area around the blade/vane leading edge was studied for both heat transfer performance and aerodynamics losses. The performance of an Impingement cooling system depends on parameters like the spent flow effect on the downstream jet, film cooling configuration, and tip flow condition. The present study focuses on analyzing the effect of these parameters on a unique impingement cooling configuration. A Liquid Crystal based technique was used to obtain the heat transfer distribution on the target surface. A novel Camera-Endoscope combination was used to capture the liquid crystal images in a confined space. Heat Transfer Contours were obtained for a total of six different cases based on differing film cooling hole configurations and tip condition. Peak heat transfer values are observed in the impingement zone along with a characteristic reduction in heat transfer as we move away from the impingement zone. The results indicated that the cross flow had a negative impact on the peak heat transfer value but improved the uniformity of heat transfer distribution. The film cooling configuration was found to affect the amount of cross flow and the location of the impingement zone of the jet. The cross flow effect is found to have reduced effect with an increase in the available number of film cooling holes leading to an increase in the peak heat transfer. The tip condition was altered for the last case in which it adversely affected the extent of jet impingement. Line plots for all the contours showed the spent flow effect. A fluid dynamic analysis of all the above effects was presented