Thermal Management Solutions for High Heat Dissipative Spacecraft Subsystems

Abstract

The primary driving force for the growth in satellite application is its demand for services like DTH, GPS, video distribution and other future networking application. These applications subsequently necessitate for high power (140 to 200 Watts) in satellite transponder and larger band width. With ever growing demands of satel- lite application, there is an increased requirement of much higher power channels. When dealing with high power of above 140 Watts, thermal management of satellite transponder employing available conventional technologies has reached their upper limits. Hence, handling these systems has become a challenge to be explored by the system designer. The proposed work described herewith is carried out on output multiplexer (MUX) as one of the potential heat dissipative subsystem which needs higher attention for e ective thermal management. The outcome of the literature survey conducted on the thermal management shows that the work reported/ published in this eld, is insu cient to provide solutions for very high power thermal control for present and future needs in this domain. The micro heat pipe ( HP) in particular has been least explored as available thermal management technique. The present work explores novel methods of using HP and Thermoelectric Cooler (TEC) and found feasible solutions implementable on board satellite. Contoured micro heat pipe (C HP) have been successfully designed, optimized and realized to demonstrate thermal performance and temperature control. TEC are also explored for future ultra high power multiplexer channels. The basis for design and analysis of C HP has been established from fundamental design procedures through a custom build software code. C HP are modeled in CAE environment(using CFD method) to visualize the physics of evaporation and conden- sation in contoured environment. The performance of C HP have been optimized by perturbing the parameters like the working uid, the internal diameter, the power in- put, the number of heat pipe, the cavity material and found a best t for application in hand. The same has been validated through experiments by manufacturing the CuHP. The output of work proposes best thermal management solutions for multiplexer sys- tem and evolves standard guidelines for design, development and realization of C HP for one complete channel of multiplexer which also can be replicated on rest of channel to get ultimate bene t of improved thermal performance of multiplexer as a whole. In a nutshell, the present work demonstrates improvement in performance of the or- der of 50% in terms of temperature gradient and a threefold increase in terms of e ectiveness, when compared to its conventional counterpart. A complete lab model of one single channel of multiplexer is realized using C HP. An alternative thermal management solution is demonstrated using TEC on a single cavity by reducing the temperature gradient to 2oC and presented in thesis. The output of test conducted using TEC shows its e ectiveness in heat removal at the cost of power consumption. C HP based thermal management solution seems to be a viable solution in present condition owing to its mass, space and power and are proposed to be used in upcom- ing GEOSAT payload of ISRO. However TEC based solution can be viable option for ultra high power future space.