Numerical investigation on the radiation performance of a crisscross liquid droplet radiator in space under different operating conditions

Abstract

Crisscross liquid droplet radiator (LDR) is a promising solution for the heat dissipation of large-power spacecraft. In this study, a three-dimensional steady numerical simulation of the radiation performance of crisscross LDR in space under different operating conditions was conducted. Significantly, the radiation interaction between adjacent droplet planes was introduced into the radiation model to accurately compute the radiative heat transfer in the crisscross droplet sheet. Simulation results indicated the radiation performance of crisscross droplet sheets deteriorated with an increase in the nonuniformity of droplet plane arrangement and the radiation power of uniform crisscross LDR was 17.7% higher than that of the most nonuniform. Moreover, there existed a critical droplet sheet angle of 72° where the pressure disturbance frequency almost did not influence the radiation performance of crisscross LDR. For a certain pressure disturbance frequency, decreasing the droplet sheet angle can expand the available operational pressure difference range. The radiation performance of high-temperature crisscross LDR was more sensitive to the variation of droplet sheet angle than that of the low-temperature crisscross LDR. Furthermore, the optimal working medium collocation scheme and droplet sheet structure for liquid metal crisscross LDR were proposed. Given the lightweight and efficiency of liquid metal crisscross LDR, the collocation scheme of working medium including liquid tin and lithium can be adopted and the droplet sheet angle should be designed as 15°. The present work can provide significant guidance for selecting suitable operating conditions for droplet generators to optimize the thermal design of a crisscross LDR.