The heat transfer processes mechanism during coolant boiling in pipes of small diameter

Abstract

This paper presents the current state of the art of methods for calculating the physical processes of heat transfer occurring during the coolant boiling in pipes of spacecraft thermal control systems. The priority tasks of rocket and space technology are modernization and technical improvement, and in general, a tendency towards an increase in the linear dimensions and power-to-weight ratio of the spacecraft is determined. However, in this case, it becomes necessary to remove a large amount of heat from more powerful equipment located on the spacecraft. For this, it is advisable to use two-phase thermal control systems. Such systems have greater productivity and efficiency, which determines the prospects for their use in planned space projects. For two-phase thermal control systems, there are a number of problems associated with the lack of reliable experimental and theoretical data on the processes of boiling and condensation in boundary conditions. The specificity of two different boiling modes, convective and nucleate, is analyzed. The described calculation methods are compared.