Investigation Of Trailing Edge Film Cooling By Jets Ejected From A Slot

The investigation is to understand the flow and heat transfer characteristics of trailing edge film cooling by jets ejected from a slot by means of detailed experimental methods. There are four parameter studied: Pressure coefficient, Discharge coefficient, Cooling effectiveness, Heat transfer coefficient.Five difference scale of slot are investigated, The range of the Reynolds number is from 5,000 to 15,000 and the Blowing ratio change from 0.5 to 2.0. the value of Pressure coefficient, Discharge coefficient, Cooling effectiveness, Heat transfer coefficient effected by Reynolds number. Blowing ratio, the ratio of slot s height to lip s thickness and the ratio of slot's width to rib's width..The results have shown that the value of Discharge coefficient is above 0.75. Along the streamwise direction, the value of Pressure coefficient will reduce first, then rise ,at last be leveling off; Cooling effectiveness on the symmetry line of central slot will reduce , Cooling effectiveness on the symmetry line of central rib will increase first ,then decrease. The difference between cooling effectiveness on the symmetry line of central slot and rib will decrease. The point where the difference becomes 0 is affected by the blowing ratio and the ratio of slot's width to rib's width. Heat transfer coefficient on the symmetry line of central slot will decline first ,then rise, at last decrease, Heat transfer coefficient on the symmetry line of central rib will rise at first ,then fell off, The difference between Heat transfer coefficient on the symmetry line of central slot and rib will decrease. The point where the difference becomes 0 is affected by the Reynolds number and the ratio of slot's width to rib's width. The Pressure coefficient, Discharge coefficient are affected little by the Reynolds number and blowing ratio. The ratio of slot's width to rib's width is main factor affecting the Pressure coefficient, Discharge coefficient and Cooling effectiveness. Cooling effectiveness on the symmetry line of central rib affected by the blowing ratio, reduce with the bowing ratio growing. Reynolds number has large effect on Heat transfer coefficient. The more littler the ratio of slot s height to lip s thickness is ,the more larger the rate of the Cooling effectiveness and the heat transfer coefficient on the symmetry line of central slot reducing ,the more farther the maximum of the Cooling effectiveness and the heat transfer coefficient on the symmetry line of central rib appears.