Evaluation of cryogenic power conditioning subsystems for electric propulsion spacecraft

Single phase heat transfer and pressure drop of liquid nitrogen in microscale heat sinks is studied experimentally in this paper. Effects of geometrical variations are characterized on the thermofluidic performance of staggered microscale pin fin heat sinks. Pitch-to-diameter ratio as well as aspect ratio of the micro pin fins is varied. The pin fins have square shape with 200 or 400µm width and are oriented at 45 degrees to the flow direction. Thermal performance of the heat sinks is evaluated for Reynolds numbers (based on pin fin hydraulic diameter) from 108 to 570. Results are presented in a non-dimensional form in terms of friction factor, Nusselt, and Reynolds numbers and are compared with the predictions of existing correlations in the literature for micro pin fin heat sinks. Comparison of flow and heat transfer performance of the micro pin fin heat sinks reveal that at a particular critical Reynolds number of ~250, pin fin heat sinks with the same aspect ratio but larger pitch ratio show a transition in both friction factor and Nusselt number. In order to better characterize this transition, visualization experiments were performed with Fluorinert PF5060 using an infrared camera. At the critical Reynolds number, for the larger pitch ratio pin fin heat sink, surface thermal intensity profiles suggest periodic flapping of the flow behind the pin fins at a Strouhal number of 0.227.

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A review of cryogenic power electronics - status and applications

Rajashekara

Akin

2013

2013 International Electric Machines &Amp; Drives Conference

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Evaluation of cryogenic power conditioning subsystems for electric propulsion spacecraft

Cited by 4 publications

References 4 publications

Novel SiGe Semiconductor Devices for Cryogenic Power Electronics

Novel SiGe Semiconductor Devices for Cryogenic Power Electronics

Single-Phase Cryogenic Flow and Heat Transfer Through Microscale Pin Fin Heat Sinks

A review of cryogenic power electronics - status and applications

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