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

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 (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 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 Nu_ave 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 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%.

Keywords:

• Flow friction
• heat transfer
• internal cooling channel
• Kagome truss cores
• turbine blade

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research work was supported by National Natural Science Foundation of China (51876157), Natural Science Foundation of Shaanxi Province in China (2019JM-096), and National Key Research and Development Program of China (2018YFB1106405).