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This paper describes the development, manufacturing and testing of an advanced heat pipe profile possessing separated arteries and small radial grooves for condensate transportation. The objective of the development was to design a heat pipe with improved heat transport capability limited by an outer cross-section of 15 mm square. The concept of the new heat pipe is based on an aluminium extrusion profile with rectangular outer shape. The central vapour core of 9.2 mm diameter is connected via small connection slots with four individual liquid channels located in the corner areas of the profile. So the liquid flow in the four channels is decoupled from vapour flow, both streaming in opposite directions. Decreasing of the pressure drop in the liquid channels and decreasing the entrainment of liquid flow to the vapour flow resulted in improved heat transport capability.

Manned space laboratories like the US Space Station Freedom or the european COLUMBUS APM are equipped with so-called racks for subsystem and payload accommodation. An important resource is air for cooling the unit internal heat sources, the avionics air. Each unit inside the rack must be supplied with sufficient amount of air to cool down the unit to the allowable maximum temperature. In the course of the COLUMBUS ECLSS project, a thermohydraulic mathematical model (THMM) of a representative COLUMBUS rack was developed to analyse and optimise the distribution of avionics air inside this rack. A sensitivity and accuracy study was performed to determine the accuracy range of the calculated avionics air flow rate distribution to the units. These calculations were then compared to measurement results gained in a rack airflow distribution test, which was performed with an equipped COLUMBUS subsystem rack to show the pressure distribution inside the rack.