TY - JOUR
T1 - A Pulsating Heat Pipe Embedded Radiator
T2 - Thermal-Vacuum Characterisation in the Pre-Cryogenic Temperature Range for Space Applications
AU - Pietrasanta, Luca
AU - Postorino, Giovanni
AU - Perna, Roberta
AU - Mameli, Mauro
AU - Filippeschi, Sauro
PY - 2020/7/3
Y1 - 2020/7/3
N2 - The use of Pulsating Heat Pipes (PHPs) in the space field is still an open issue because of the lack of data obtained during actual operation in relevant environment. A considerable amount of data is available in the literature on the thermal response of PHPs to a variable gravity condition and on the operation in the cryogenic field but in both cases the heat load at the condenser is rejected by convection to a constant temperature sink. On the other hand, barely any work in the PHP’s literature deals with thermal radiation to a low temperature sink as only heat transfer mode. The present work attempts to fill the gap by testing a PHP radiator (16 turns, 1.1 mm inner diameter, 50% filled with FC-72 at 293K) in thermo-vacuum conditions in horizontal orientation at different heat loads and different environment (chamber) temperature. Fluid pressure measurements coupled with the frequency analysis characterised the effect of the cold source temperature on the device operational limits and efficiency. Results show that the device thermal performance in the radiative configuration is mostly affected by the lower operating temperatures needed to obtain a sensible heat rejection, rather than the heat transfer mode itself. The decrease of the environment temperature shortens the operational heat load range: the start-up occurs at higher heat input levels while the thermal crisis occurs at lower heat loads. The frequency analysis reveals that the equivalent thermal resistance is positively affected by higher values of the dominant frequency for all the cases.
AB - The use of Pulsating Heat Pipes (PHPs) in the space field is still an open issue because of the lack of data obtained during actual operation in relevant environment. A considerable amount of data is available in the literature on the thermal response of PHPs to a variable gravity condition and on the operation in the cryogenic field but in both cases the heat load at the condenser is rejected by convection to a constant temperature sink. On the other hand, barely any work in the PHP’s literature deals with thermal radiation to a low temperature sink as only heat transfer mode. The present work attempts to fill the gap by testing a PHP radiator (16 turns, 1.1 mm inner diameter, 50% filled with FC-72 at 293K) in thermo-vacuum conditions in horizontal orientation at different heat loads and different environment (chamber) temperature. Fluid pressure measurements coupled with the frequency analysis characterised the effect of the cold source temperature on the device operational limits and efficiency. Results show that the device thermal performance in the radiative configuration is mostly affected by the lower operating temperatures needed to obtain a sensible heat rejection, rather than the heat transfer mode itself. The decrease of the environment temperature shortens the operational heat load range: the start-up occurs at higher heat input levels while the thermal crisis occurs at lower heat loads. The frequency analysis reveals that the equivalent thermal resistance is positively affected by higher values of the dominant frequency for all the cases.
KW - Embedded radiator
KW - Pulsating heat pipe
KW - Space applications
KW - Thermal control system
KW - Thermal-vacuum chamber
UR - http://www.scopus.com/inward/record.url?scp=85087639454&partnerID=8YFLogxK
U2 - 10.1016/j.tsep.2020.100622
DO - 10.1016/j.tsep.2020.100622
M3 - Article
SN - 2451-9049
VL - 19
JO - Thermal Science and Engineering Progress
JF - Thermal Science and Engineering Progress
M1 - 100622
ER -