Experimental study of flow characteristics in a turn-over channel with ribs and film cooling

The turn-over channel is an important part of the internal cooling structure of modern turbine blade. Its flow and heat transfer performance are crucial for cooling effectiveness. The turn-over channel of a real turbine blade was simplified, in this paper, to be a ribbed rectangular passage with variable cross section area and its coolant flow characteristics were studied experimentally under the influence of film cooling outlet. Experimental results show that the effective pressure distribution of the exit section is different and the flow friction decreases due to the influence of film bleeding. Flow process was controlled by factors such as choke ratio, width to length ratio, the ratio of film outlet to the main flow and the inlet Reynolds number, etc.