Abstract
Two Closed Loop Pulsating Heat Pipes (CLPHPs) are tested on board REXUS 18 sounding rocket in order to obtain data over a relatively long microgravity period (approximately 90 s). The CLPHPs are partially filled with FC-72 and have, respectively, an inner tube diameter larger (3 mm) and slightly smaller (1.6 mm) than the critical diameter evaluated in static Earth gravity conditions. On ground, the small diameter CLPHP effectively works as a Pulsating Heat Pipe (PHP): the characteristic slug and plug flow pattern forms inside the tube and the heat exchange is triggered by thermally driven self-sustained oscillations of the working fluid. On the other hand, the large diameter CLPHP works as a two- phase thermosyphon in vertical position and doesn't work in horizontal position: in this particular condition, the working fluid stratifies within the device as the surface tension force is no longer able to balance buoyancy. Then, the idea to test the CLPHPs in reduced gravity conditions: as the gravity reduces the buoyancy forces becomes less intense and it is possible to recreate the typical PHP flow pattern also for larger inner tube diameters. This allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience low gravity conditions due to a failure in the yoyo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described.
Highlights
Pulsating Heat Pipes (PHPs) are novel two-phase passive heat transport devices that seem suitable for the thermal management of electronics components in space related applications
The Closed Loop Pulsating Heat Pipes (CLPHPs) are partially filled with FC-72 and have, respectively, an inner tube diameter larger (3 mm) and slightly smaller (1.6 mm) than the critical diameter evaluated in static Earth gravity conditions
The small diameter CLPHP effectively works as a Pulsating Heat Pipe (PHP): the characteristic slug and plug flow pattern forms inside the tube and the heat exchange is triggered by thermally driven self-sustained oscillations of the working fluid
Summary
Pulsating Heat pipe Only for Space (PHOS): results of the REXUS 18 sounding rocket campaign. This content has been downloaded from IOPscience. Please scroll down to see the full text. Ser. 655 012042 (http://iopscience.iop.org/1742-6596/655/1/012042) View the table of contents for this issue, or go to the journal homepage for more. Download details: IP Address: 194.81.199.106 This content was downloaded on 18/11/2015 at 13:50 Please note that terms and conditions apply
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have