High efficiency, low pressure drop two-phase condenser: Final report

Abstract

Capillary pumped two-phase systems are considered to be: -Prime candidates to provide efficient thermal management systems for future advanced spacecraft. -Promising candidates for the thermal control of advanced larger instruments (e.g. laser-based earth observation instruments) or microgravity experiments. In such capillary pumped two-phase systems, a high-efficient zero-g condensation heat transfer, low-pressure drop condenser will be required. This report describes all analytical and experimental activities (of NLR, prime contractor, and the subcontractors Bradford Engineering and Daimler Benz Aerospace-Space Infrastructure) to develop a high efficiency low pressure drop condenser and to bring it up to pre-qualification level: •The inventory, dedicated to a literature review of potential concepts and means to improve condenser efficiency and to lower pressure drop, followed by a trade-off, supported by the necessary thermo-hydrauhc and structural analyses, yielding the definition of the design. •The manufacture of the defined condenser, the execution of an extensive test programme, performed under conditions reflecting, as close as possible, realistic in-orbit conditions and the evaluation of test results with thermo-hydraulic model predictions. The resulting condenser combines the high efficiency of a direct condensation annular configuration and the low pressure drop of a channelled configuration (as it is shown in detail by the results of performance and acceptance tests): For 2{X) W condensed power, the temperature drop between evaporator inlet and heat pipe core temperature is smaller than 7.5 °C, with a pressure drop of less than 400 Pa. The tests also confirmed that there is no significant difference in performance for vertical and horizontal orientations.