Abstract
A novel redundant cryocooler system, featuring two cryocooler cold heads linked via separate nitrogen pulsating heat pipe (PHP) thermal switches to a common cold plate, is developed and performance tested. The setup allows the cold plate to be maintained at the design temperature when one of the two cryocoolers is inactive by leveraging the low thermal conductivity of the static vapor in the associated dry PHP as insulation from the warm inactive cryocooler. The PHP thermal switches operate passively and require no mechanical actuation, inherently offering a highly reliable switching mechanism. PHP heat load, effective thermal conductivity, effective conductance, evaporator temperature, and condenser temperature measurements are presented for a range of fill ratios and applied cold plate heat loads. The tested PHPs can transfer at least 16 W before dryout and have effective thermal conductivities in the ON and OFF switch states ranging from 10,000 W/m-K to 55,000 W/m-K and 8 W/m-K to 50 W/m-K, respectively. Thermal switch performance is characterized by the switching ratio – the ratio of its effective conductance in the ON state to that in the OFF state – and is demonstrated to approach about 2500 for the tested PHPs. The parasitic heat load through the PHP switch in the OFF state (about 0.6 W) is found to be about 4 percent of its maximum tested ON state heat transfer capacity (about 16 W).
Accepted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
