Limitations in Variable Conductance Heat Pipe Performance and Control Predicted by the Current Steady-State Model Developed at NLR

摘要

A uniaxial model for the transient performance of gas-loaded variable conductance heat pipes is discussed. The model has to be easily implementable in existing spacecraft thermal analyzer computer programs. A steady-state version of the model is available. It accounts for diffusion at the vapor/gas front (shown to be negligible), radial conduction in the wall and wick, and inertia and friction of the moving vapor. A parameter study was carried out to design a heat pipe and to define test conditions for the experimental verification of the model. Results illustrate that inertia and friction can induce considerable limitations in performance and control.