Modeling a Loop Heat Pipe (LHP) at spacecraft system level could be carried out - at first approximation - by simply using a constant thermal conductance on the complete range of the evaporator power: from the lowest possible power up to the maximum value depending on the available capillary pumping capability. This approach leads however to an overestimation of Loop Heat Pipe performance, especially at low power. Moreover, the sub-cooled condenser zone could reach the temperature level such that the radiator heaters are activated to prevent the LHP working fluid from freezing. Then, the precise determination of equipment temperatures functioning at low dissipation rate as well as the activation of radiator heaters at satellite cold mode requires a quite accurate modeling of the LHP. Astrium has developed a simplified thermal model for LHP architecture design and justification. This model is currently used for the development of different thermal bus for the cooling and temperature regulation of instruments and equipments. The LHP module software is compatible with any standard system level thermal model, without requiring the use of any dedicated heavy hydraulic software. The software has to be included in the satellite system model, allowing to predict the LHP specific operations such as: instabilities and performance oscillations; start & stop operations depending on environment variations and dissipative source conditions, active performance control via LHP heat leak regulation. Owing to a wide test campaign of different technologies and architectures, it has been possible to achieve a very high level of accuracy in the simulation results. An overview of different tested cases and simulations is presented. Moreover, a correlation of an active regulation with a mini-Loop Heat Pipe is shown and discussed.
Loop heat pipe thermal model
2012
6 Seiten, Bilder, 2 Quellen
Conference paper
English
Loop heat pipe for avionics thermal control
Tema Archive | 1996
|Loop Heat Pipe for Avionics Thermal Control
SAE Technical Papers | 1996
|