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Title: Effect of Property Variations on the Operation of Superfluid Porous Plug Pumps

Abstract

The flow of superfluid helium through channels that are long compared to their diameter has profiles with large pressure and temperature maxima. The maxima are proportional to the length of the channel divided by the diameter squared. This phenomenon occurs in porous materials. The peaks result from the transition of the superfluid component to the normal component. Temperature gradients, and the associated property variations, drive the transitions. When the average pore diameter is of the order of 10 microns or smaller, this effect modifies the operation of superfluid devices significantly. We apply the theory of superfluid transition to the operation of the porous plug pump. A modification of the Green's function method using step functions is used to derive the formulas associated with superfluid transition. We present the operational formulas used to optimize a design for a particular application. The temperature maxima may cause a pump to quench when the peak temperature reaches the lambda point. The integrated average temperature is higher than the end-point average. This causes the mass flux to decrease and the heat needed to drive the flow to increase compared to the constant property solution. The superfluid wind tunnel is a special case of this analysis.

Authors:
 [1]
  1. University of Colorado at Boulder, Boulder, CO, 80309 (United States)
Publication Date:
OSTI Identifier:
20800220
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 823; Journal Issue: 1; Conference: Cryogenic engineering conference, Keystone, CO (United States), 29 Aug - 2 Sep 2005; Other Information: DOI: 10.1063/1.2202443; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; GREEN FUNCTION; HEAT; HELIUM; HELIUM 4; LAMBDA POINT; OPERATION; POROUS MATERIALS; PUMPS; SUPERFLUIDITY; TEMPERATURE GRADIENTS; VARIATIONS; WIND TUNNELS

Citation Formats

Snyder, H. A. Effect of Property Variations on the Operation of Superfluid Porous Plug Pumps. United States: N. p., 2006. Web. doi:10.1063/1.2202443.
Snyder, H. A. Effect of Property Variations on the Operation of Superfluid Porous Plug Pumps. United States. doi:10.1063/1.2202443.
Snyder, H. A. Thu . "Effect of Property Variations on the Operation of Superfluid Porous Plug Pumps". United States. doi:10.1063/1.2202443.
@article{osti_20800220,
title = {Effect of Property Variations on the Operation of Superfluid Porous Plug Pumps},
author = {Snyder, H. A.},
abstractNote = {The flow of superfluid helium through channels that are long compared to their diameter has profiles with large pressure and temperature maxima. The maxima are proportional to the length of the channel divided by the diameter squared. This phenomenon occurs in porous materials. The peaks result from the transition of the superfluid component to the normal component. Temperature gradients, and the associated property variations, drive the transitions. When the average pore diameter is of the order of 10 microns or smaller, this effect modifies the operation of superfluid devices significantly. We apply the theory of superfluid transition to the operation of the porous plug pump. A modification of the Green's function method using step functions is used to derive the formulas associated with superfluid transition. We present the operational formulas used to optimize a design for a particular application. The temperature maxima may cause a pump to quench when the peak temperature reaches the lambda point. The integrated average temperature is higher than the end-point average. This causes the mass flux to decrease and the heat needed to drive the flow to increase compared to the constant property solution. The superfluid wind tunnel is a special case of this analysis.},
doi = {10.1063/1.2202443},
journal = {AIP Conference Proceedings},
number = 1,
volume = 823,
place = {United States},
year = {Thu Apr 27 00:00:00 EDT 2006},
month = {Thu Apr 27 00:00:00 EDT 2006}
}