Du Clou S., Brooks M.J., Lear W.E., Sherif S.A., Khalil E.E.
University of Kwa Zulu-Natal, Kwa Zulu-Natal, South Africa; University of Florida, Gainesville, FL, United States; Cairo University, Cairo, Egypt; Mechanical Engineering, Durban, South Africa; Mechanical and Aerospace Engineering, P.O. Box 116300, South Africa
Du Clou, S., University of Kwa Zulu-Natal, Kwa Zulu-Natal, South Africa, Mechanical Engineering, Durban, South Africa; Brooks, M.J., University of Kwa Zulu-Natal, Kwa Zulu-Natal, South Africa, Mechanical Engineering, Durban, South Africa; Lear, W.E., University of Florida, Gainesville, FL, United States, Mechanical and Aerospace Engineering, P.O. Box 116300, South Africa; Sherif, S.A., University of Florida, Gainesville, FL, United States, Mechanical and Aerospace Engineering, P.O. Box 116300, South Africa; Khalil, E.E., Cairo University, Cairo, Egypt, Mechanical Engineering, Durban, South Africa
Thermal management on space vehicles is dominated by passive systems, including materials, coatings, louvers and heat pipes, and active systems, including pumped liquid loops. Recently, the pulse thermal loop was proposed as a novel technology to provide improved heat transfer over passive systems in the moderate to high heat flux range and as a sustainable alternative to active systems, where an electric pump is undesirable. In this work, the performance of an experimental pulse thermal loop with refrigerant R-134a is characterized using a test facility incorporating variable heat input, driving pressure differential, and line lengths. Three automated control schemes are investigated, which provide flexibility in design. The performance of the device is mapped for a range of power levels and compared with data from the literature, highlighting the operating limits. The pulse thermal loop provides effective thermal control for a range of heat loads from 100 to 800 W while maintaining the source temperature at below 60°C. It provides an approximately isothermal heat sink even though it is an oscillatory cycle. This is achieved at various driving pressure differentials from 3 to 14 bar and pulse frequencies from 0.42 to 0.08 Hz. A smaller pressure differential and an increased pulse frequency provide improved heat transfer at the source.