STUDY ON FLOW AND HEAT TRANSFER CHARACTERISTICS OF COOLING CHANNEL FILLED WITH X-SHAPED TRUSS ARRAY

In order to enhance the cooling performance of turbine blades, novel cooling channels filled with X-shaped truss array were investigated in this study. The flow mechanism and heat transfer characteristic of the cooling channel filled with X-shaped truss array were analyzed numerically. The empirical correlations of friction coefficient and Nusselt number related to the inlet Reynolds number (10000-60000) and truss rod inclination angle (30-45 degrees) were fitted. The results show that the secondary flow vortex in the channel and the Nusselt number on the channel wall both show periodic distributions along the streamwise direction. The row-averaged Nusselt number and friction coefficient of the channel first decrease quickly and then decrease slowly along the streamwise direction. When truss rod inclination angle increases from 30-60 degrees, the whole-averaged Nusselt number and the whole friction coefficient of the channel increase by 25.4-52.3% and 1.19-1.33 times, respectively under different Reynolds number. The channel with truss rod inclination angle of 45 degrees has the best comprehensive thermal performance. In all cases, the ratio of heat transfer quantity of the truss rod surface to the total heat transfer quantity of the channel ranges from 22.9-42.3%. The increase of Reynolds number improves the heat transfer quantity of the channel wall and the increase of truss rod inclination angle reduces the heat transfer quantity of the channel wall.