Development of cryogenic loop heat pipe for deep space mission
Cryogenic loop heat pipe (CLHP) is an efficient two-phase heat transfer device for cooling electronic components with cryogenic operating temperature range (2-240 K), such as an infrared detector. Compared to connecting an electronic component directly to a cryocooler, CLHP results in a higher flexible arrangement of the heat sources and the cryocooler, less disturbance from the cryocooler�s vibration. The final goal of this research is to realize the future space application of CLHP. In this research, a CLHP was developed to demonstrate the fabrication technology, and the detailed design method is shown. Nitrogen was selected as the working fluid. The CLHP was designed with more than 10 W heat transfer capability for a 2 m heat transport distance in the operating temperature range of 80-110 K. A liquid nitrogen tank was used for cooling condensing line. To assist the startup from a supercritical state, the CLHP was tested in a gravity-assisted attitude: The condenser was located at a higher position than that of the evaporator so that the evaporator and the compensation chamber was filled with liquid nitrogen at the startup. A 300 ml gas reservoir was installed in the CLHP. The inventory of nitrogen in the CLHP was 11.5 g, and the charged pressure was 3.26 MPa at 300 K. A sintered stainless steel wick was inserted into the evaporator with a shrink fitting method. To reduce the heat leak to the ambient, the CLHP was covered by insulation with high infrared reflectance and tested in a vacuum chamber. A mathematical model was proposed to predict the operating performance of CLHP. The numerical results will be evaluated with experiments.
Takuya Adachi, Institute of Fluid Science, Tohoku University
Kimihide Odagiri, Institute of Space and Astronautical Science
Hiroyuki Ogawa, Institute of Space and Astronautical Science
Hiroki Nagai, Institute of Fluid Science, Tohoku University
ICES201: Two-Phase Thermal Control Technology
The 50th International Conference on Environmental Systems was held virtually on 12 July 2021 through 14 July 2021.