MEASURING TECHNIQUE AND PROGRESS ON THERMAL PROPERTIES OF SECONDARY REFRIGERANT AT LOW TEMPERATURE

The temperature in spacecraft is controlled by the forced convective heat transfer of secondary refrigerant in the thermal control system.When secondary refrigerant is developed and selected based on the performance requirements,the thermal property parameters of fluid are required to measure in low temperature.This article summarizes the measuring technique on thermal properties of secondary refrigerant,including the testing methods of density,freezing point,boiling point and viscosity and so on.Adiabatic calorimeter is the best method for testing specific heat capacity at low temperature,and radial heat flow method is suitable for measuring thermal conductivity at low temperature.