Flow of helium II through porous plugs

✍ Scribed by H.D. Denner; G. Klipping; I. Klipping; J. Menzel; U. Ruppert

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 434 KB
• Volume: 18
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(78)90177-7

✦ Synopsis

Among the projects under development for Spacelab, infrared telescopes are of special interest from the cryogenic point of view. All ir detectors require low temperatures, some of them as low as 0.3 K.

There is no doubt that He II is indispensable as a coolant for this application since at temperatures as low as 1.5 K it provides the highest possible cooling capacity per unit volume and per unit weight, and the extremely high thermal conductivity, together with fdm flow, favours isothermal conditions in the dewar. The development of an optimized He II cooling system to be operated under zero gravity is thus one of the current challenges for cryogenic engineers.

Suitable means of achieving temperature control by controlled evaporation of the coolant will almost certainly Include a porous plug, which makes use of the thermomechanical effect to confine the superfluid liquid. 1-3 Porous plugs (superfflters) have for many years proved successful in automatic refdling devices for He II. The flow of He II through such plugs has been investigated repeatedly and its principles are more or less understood. 7-9