Pulsating Heat Pipe for Cryogenic Fluid Management

A passive Pulsating Heat Pipe (PHP) system is proposed to distribute cooling over broad areas with low additional system mass. The PHP technology takes advantage of the large latent heat associated with phase change of a working fluid that is confined to small capillaries to carry heat efficiently from evaporator regions to a condenser that is attached to the cold head of the cryocooler. This system will have an advantage over other distributed cooling approaches because it will be modular and can interface with any cooler that provides the required cooling power at the load temperature. The cooler may be a Stirling cooler, Pulse Tube cooler, reverse-Brayton cooler, Joule Thompson cooler, or some hybrid combination of these. Because the fluid flow is driven by fluid phase change caused by a temperature difference between the evaporators and the condenser, the loop is self-regulating. Flow is induced only when there is a thermal load. Also, because surface tension forces are dominant in the small capillaries of the PHP, this technology is suited for use in microgravity.