MEMS 기반 대전입자형 가변 방사율 라디에이터의 설계 및 열 제어 성능 평가

Abstract

The radiator is a thermal control device that radiates waste heat of satellite from a spacecraft to outer space by radiant heat transfer processes. However, radiating heat also in cold case, the radiator had require to thermal control by heater. The variable emissivity radiator that can change the emissivity properties in accordance with a temperature condition was developed to solve the conventional drawback. But, the conventional variable emissivity radiator was difficult to apply to small satellite because that has a large weight and mass. MEMS(Micro Electro Mechanical System)-base louver and shutter type variable emissivity radiators was developed to solve weight and mass of the conventional variable emissivity radiator. However, there are some drawbacks such as a structural safety of the mechanical moving parts under sever launch environment and constant power consumption to maintain the intended emissivity. In this study, to overcome above drawbacks, proposed a MEMS-base charged particle type variable emissivity radiator, that can change the emissivity property according to the direction of electronic field by using electric charge of the bead. And can minimize the power consumption for maintain to emissivity due to bead holds to the partition by electrostatic force. In this study, a principle and operating characteristics of MEMS-base charged particle type variable emissivity radiator was analyzed and performed to test by bead operating. And it performed the optimization design of thermo-optical property for MEMS-base charged particle type variable emissivity radiator through the thermal analysis. The effectiveness of the optimized radiator design has been demonstrated through the comparison of efficiency with the fixed emissivity radiator. And MEMS-base charged particle type variable emissivity radiator, which was made in MEMS process, measured the emissivity of alumina bead, quartz wafer and silver coating for performance verification. And calculated the effective emissivity of the measured emissivity using the mathematical calculations, analyzed the effective emissivity of open and close state. Through test, that performed the evaluation of thermal control performance by change of emissivity and it analyzed problem via thermal analysis model. The applicability of the MEMS-base charged particle type variable emissivity radiator has been demonstrated through improved thermal analysis model.