A 3-D model of superfluid helium suitable for numerical analysis

The two-fluid description is a very successful phenomenological representation of the properties of Helium II. A 3-D model suitable for numerical analysis based on the Landau-Khalatnikov description of Helium II is proposed. In this paper we introduce a system of partial differential equations that is both complete and consistent as well as practical, to be used for a 3-D solution of the flow of Helium II. The development of a 3-D numerical model for Helium II is motivated by the need to validate experimental results obtained by observing the normal component velocity distribution in a Helium II thermal counter-flow using the Particle Image Velocimetry (PIV) technique

Normal fluid eddies in the thermal counterflow past a cylinder

A recent Particle Image Velocimetry (PIV) experiment in He II counterflow around a cylindrical obstacle showed the existence of apparently stationary normal fluid ddies both downstream (at the rear) and upstream (in front) of the cylinder. This rather surprising result does not have an analogue in experimental observations of classical fluid flows. We suggest that the explanation for the apparent stability of such eddies can be provided entirely from the viewpoint of classical fluid dynamics. We also discuss a possible connection between the emergence of the normal fluid eddies and the polarization of the vortex tangle in superfluid.Comment: submitte

Final report on fluid dynamics of supercritical helium within cable-in-conduit conductors

The enclosed report summarizes work carried out under DOE/MFE support during the past four years. Emphasis is placed on progress during the last year. Results of experiments on pressure drop and heat transfer within several Cable-in-Conduit conductors are described. These results are compared to models developed for flow in similar geometries. The work provides a basis for design of magnets using CIC conductors in fusion magnetic systems

Liquid Helium Fluid Dynamics Studies. Final Report, June 1, 1992--May 31, 1996

The present report pertains to work carried out over the grant period (June 1, 1992 to May 31, 1996) under the support of the U.S. Department of Energy-Division of High Energy Physics. The report is divided into categories according to the 1992 grant statement of work. This report discusses the following topics: two phase flow studies; transient heat transfer studies; co- and counter-current He II heat exchangers; and He II heat transport in cylindrical geometry

[Fluid dynamics of supercritical helium within internally cooled cabled superconductors. Annual report]

The Applied Superconductivity Center of the University of Wisconsin-Madison proposes to conduct research on low temperature helium fluid dynamics as it applies to the cooling of internally cooled cabled superconductors. Such conductors are used in fusion reactor designs including most of the coils in ITER. The proposed work is primarily experimental involving measurements of transient and steady state pressure drop in a variety of conductor configurations. Both model and prototype conductors for actual magnet designs will be investigated. The primary goal will be to measure and model the friction factor for these complex geometries. In addition, an effort will be to study transient processes such as heat transfer and fluid expulsion associated with quench conditions

[Fluid dynamics of supercritical helium within internally cooled cabled superconductors]

The Applied Superconductivity Center of the University of Wisconsin-Madison proposes to conduct research on low temperature helium fluid dynamics as it applies to the cooling of internally cooled cabled superconductors (ICCS). Such conductors are used in fusion reactor designs including most of the coils in ITER. The proposed work is primarily experimental involving measurements of transient and steady state pressure drop in a variety of conductor configurations. Both model and prototype conductors for actual magnet designs will be investigated. The primary goal will be to measure and model the friction factor for these complex geometries. In addition, an effort will be made to study transient processes such as heat transfer and fluid expulsion associated with quench conditions

STABILITY STUDIES OF CABLED CONDUCTORS IN He I AND He II

Des expériences ont été effectuées pour étudier les principes physiques qui gouvernent la stabilité de supraconducteurs composites câblés refroidis par un bain He I ou He II.Experiments have been performed to study the physical principals governing the stability of cabled composite superconductors cooled by pool boiling He I and He II

Studies of heat transport to forced-flow He II

Analytical and experimental studies of heat transport to forced-flow He II are reported. The work is pertinent to the transfer of He II in space. An analytical model has been developed that establishes a condition for two-phase flow to occur in the transfer line. This condition sets an allowable limit to the heat leak into the transfer line. Experimental measurements of pressure drop and flow meter performances indicate that turbulent He II can be analyzed in terms of classical pressure drop correlations

Progress in modular-stellarator fusion-power-reactor conceptual designs

Recent encouraging experimental results on stellarators/torsatrons/heliotrons (S/T/H) have revived interest in these concepts as possible fusion power reactors. The use of modular coils to generate the stellarator topology has added impetus to this renewed interest. Studies of the modular coil approach to stellarators by UW-Madison and Los Alamos National Laboratory are summarized in this paper