Numerical Simulation Study on Cooling of Film-hole-free Pipe Network Targeting the Mid-chord Region of Turbine Blades
In order to address the bottleneck problems such as limited cooling performance improvement of traditional blade cooling methods,large demand for cold air,and uneven heat transfer,a new air-free membrane pipe network cooling structure for the mid-chord region of blades was proposed in this paper.The flow and heat transfer characteristics of the pipe network cooling structure were compared with those of typical double-wall structures with gas film holes by numerical simulation method.And the effects of different cold air inlet Reynolds numbers and temperature ratios on the cooling performance of the pipe network were further analyzed.The results show that the average surface temperature of the new pipe net-work cooling structure is 9.7 K lower than that of the double-wall cooling structure,and the surface tem-perature distribution is more uniform,which shows that the cooling structure of the pipe network has the advantages of good cooling performance,low consumption of cold air and uniform temperature distribu-tion.With the increase of cold air inlet Reynolds number from 90 000 to 180 000,the blade surface tem-perature of the pipe network cooling structure decreases by 64.4 K,and the overall heat transfer perform-ance becomes significantly better.When the temperature ratio decreases from 2.80 to 2.15,the average blade temperature increases gradually.The cooling structure of pipe network can greatly improve the cool-ing performance of the mid-chord region,but the leading edge and trailing edge are not greatly improved,so it is necessary to further optimize the internal cooling structure.
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