Numerical and Experimental Investigations of Axial Groove and Wire Mesh Heat Pipe for Spacecraft Payload Thermal Management

Abstract

For maintaining the temperature of spacecraft payload equipment within its operating range, proper thermal management is required. Higher heat dissipating equipment of the spacecraft must be prevented from overheating. So, passive thermal control devices are used to maintain the temperature of on board equipment. The thought behind using the passive thermal control devices is to minimize power requirement in payload systems. In present study, the focus lies on axially grooved and wire mesh heat pipe development. In this study, work has been carried out for development of ammonia based axially grooved heat pipe for payload panels. Dual core ammonia charged aluminum heat pipe with 1 meter length is used for experimentation. Steady state experimental investigation has been carried out with constant heat input and constant sink temperature of 20 C. Also, development of water charged copper heat pipe with wire mesh wick structure has been done. The numerical model has been developed for axially grooved as well as wire mesh heat pipes to investigate the performance parameters like pressure drop variation of vapor and liquid, capillary radius variation along the length, mass flow rate, velocity of liquid and vapor, total thermal resistance to predict the temperature difference along the length and maximum heat transport capacity. This thesis deals with theoretical calculation of maximum heat transport capacity by limit calculation, charge quantity estimation and figure of merit. The numerical model has been developed considering the effect of liquid vapor inter facial shear stress, contact angle, thin film resistance at evaporator and condenser section and liquid vapor interface resistance in terms of effective heat transfer co efficient. Numerical model has been solved using MATLAB software package of MathWorks, Inc and validated with the results of previously reported open literature. Experiments have been performed for axially grooved heat pipe in vacuum chamber. Experimental results are compared with the numerical predictions. So that performance of the heat pipe can be evaluated. Parametric study has been done to optimize the geometrical parameters of heat pipe.