Experimental Investigation of the Local Heat Transfer Characteristics at the Inner Side of the Midchord Region near Film Cooling Holes

Experimental investigation of the turbine blade local heat transfer characteristics at the inner side of the mid-chord region near film holes was conducted,with and without impingement cooling.Under no impingement condition,the investigation was carried out with different crossflow Reynolds Numbers and different density flow ratios of film outflow to cross flow.The research results indicate that the local heat transfer near the film cooling holes is enhanced with the increase of the cross flow Reynolds Numbers and density flow ratios.The local heat transfer characteristics aft the film holes are better than that ahead the film holes.The closer to the holes the stronger heat transfer will be,regardless of ahead or aft the film holes.A comparison of extraction effect between 30° and 90° film cooling holes was conducted also.Under the condition with impingement cooling,through the experimental data,effect of flow parameters such as impinging Reynolds Numbers and density flow ratios on the local heat transfer characteristics were obtained.