Abstract
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 (α = 45°–90°) for the DRKTC on the friction factor (f) and average Nusselt number (Nuave) 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 α has a greater influence on the f, which enhances about 1.2 times when the a changes from 45° to 90°, and the effect of the Nuave is small, which only increases by 4.09%. A small α 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 Nuave 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 Nuave are fitted with a deviation of about 5%.
Disclosure statement
No potential conflict of interest was reported by the author(s).