Heat transfer characteristics of a channel filled with the array of drop-shaped Kagome truss cores

A staggered array of Kagome truss cores with drop-shaped rods is proposed as a new turbulator for a typical rectangular internal cooling channel at the trailing edge of a turbine blade. Under the Re range of 5000-25000, flow field and heat transfer characteristics in the channel are comparatively analyzed for two Kagome truss cores with drop-shaped (DRKTC) and common cylindrical (CYKTC). The effect of rod diameter (d = 1-3 mm) and tail angle (alpha = 45 degrees-90 degrees) for the DRKTC on the friction factor (f) and average Nusselt number (Nu(ave)) at the bottom wall of the channel were studied. The results show that the f of the DRKTC reduces by 29.4% and the comprehensive thermal coefficient (F) increases by 6.82% compared to the CYKTC under the same porosity and operating conditions. The parameter alpha has a greater influence on the f, which enhances about 1.2 times when the a changes from 45 degrees to 90 degrees, and the effect of the Nu(ave) is small, which only increases by 4.09%. A small alpha is a good choice for reducing pressure drop. The size of the rod windward area depends on the rod diameter, when the d increases from 1 mm to 3 mm, the Nu(ave) increases by 35.8%, and the f sharply increases by 153.6%. Based on the simulation results data, the fitting relations of the f and Nu(ave) are fitted with a deviation of about 5%.