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Description
The need of cooling devices that are lightweight, low powered, physically flexible, easily manufactured and most importantly exhibit high heat transfer rates are requirements that space agencies demand in a cooling system. Therefore, Pulsating Heat Pipes (PHPs) are being extensively investigated to provide these requirements. This paper summarizes the current development of cryogenic Pulsating Heat Pipes with single and multiple evaporator sections built and successfully tested at UW-Madison. Recently, a Helium based Pulsating Heat pipe with three evaporator and three condenser sections has been operated at fill ratios between 20 % and 90 % operating temperature range of 2.9 K to 5.19 K, resulting in a maximum effective thermal conductivity up to 50,000 W/m-K. In addition, a Nitrogen Pulsating Heat Pipe has been built with three evaporator sections and one condenser section. This PHP achieved a thermal performance between 32,000 W/m-K and 96,000 W/m-K at fill ratio ranging from 50 % to 90 %. Split evaporator sections are very important in order to spread cooling throughout an object of interest with an irregular temperature distribution or where multiple cooling locations are required. Hence this type of configurations could be applied to cryo-propellant tanks, superconducting magnets and photon detectors.
