Cooling characteristics of array jet impinging on grooved target surface imitating blue whale skin

Abstract

In this paper, based on the idea of bionics and imitating the groove structure of the blue whale skin surface, a composite cooling structure with array jet impinging on groove target surface is proposed for the cooling of combustion chamber. For the working conditions of high Reynolds number (Re = 10,000 to 70,000) and high heat flux (q = 10 kW·m-2), this paper firstly explores the heat transfer characteristics of the flat target surface and the grooved target surface under different Re through experiments. The flow characteristics of the array jet impinging on groove target surface are studied by numerical simulation, and the influence of the existence of grooves on the flow field is analyzed. The research results show that the presence of grooves enhances the fluid disturbance near the wall, and the use of grooved target surfaces can significantly reduce the target surface temperature, increase Nu, and reduce the friction factor f. Compared with the flat target surface, the average temperature of the groove target surface decreases by 2.13%, the average Nusselt number Nuave increases by 43.3%, and the average friction factor f decreases by 3.79%. In addition, the comprehensive heat transfer factor F of the grooved target surface is all greater than 1.06, which indicates that the comprehensive heat transfer performance of the groove target surface is better. In addition, with the increase of Re, the target surface Nuave increases and the friction factor f decreases. When Re increases from 10,000 to 70,000, the Nuave of the groove target surface increases by 85.9%, and f decreases by 6.16%.