Development and Testing of a High Performance Quadro-Groove Heat Pipe 911481
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.
The azimuthal liquid distribution can be performed either with small circumferential grooves or with wick systems pressed to the vapour core wall. A special machining technique has been developed to cut small circumferential grooves of approximately 0.15 mm width and 0.2 mm depth into the vapour core walls over the whole heat pipe length of approximately 2.5 m.
Five different configurations of quadro-groove based high performance heat pipes have been built and tested. The test results obtained indicated an improved heat transport capability about three times higher compared to that of a common axial grooved heat pipe with rectangular grooves.