Performance analysis of reciprocating regenerative magnetic heat pumping. Final report [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1994.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 99 pages : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- Transient flow phenomena in the regenerator tube of reciprocating magnetic heat pumps have been studied numerically and experimentally. In the numerical study, two approaches were taken: (1) solving the energy balance equations for fluid through a porous bed directly and (2) solving the Navier-Stokes equations with a buoyancy force term in the momentum equation. A flow thermal mixing problem was found in both approaches because of the piston-like motion of the regenerator tube that hinders the development of the temperature. The numerical study results show that a 45 K temperature span can be reached in 10 minutes of charge time through the use of a 7-Tesla magnetic field. Using the second numerical approach, temperature stratification in the regenerator fluid column was clearly indicated through temperature rasters. The study also calculates regenerator efficiency and energy delivery rates when heating load and cooling load are applied. Piecewise variation of the regenerator tube moving speed has been used in the present numerical study to control the mass flow rate, reduce thermal mixing of the flow and thus the regenerative losses. The gadolinium`s adiabatic temperature has been measured under 6.5 Tesla of magnet field and different of operating temperatures ranging from 285 K to 320 K. Three regenerative heat pumping tests have also been conducted based on the Reynolds number of the regenerator tube flow, namely Re=300, Re=450, and Re=750 without loads. Maximum temperature span are 12 & 11 K and 9 K for the case of Re=300, Re=450 and Re=750, respectively. Experimental data are in good agreement with the numerical calculation results, and have been used to calibrate the numerical results and to develop a design database for reciprocating-type room-temperature magnetic heat pumps.
- Published through SciTech Connect.
Murphy, R.W.; Chen, F.C.; Mei, V.C.; Lubell, M.S.; Chen, D.T.; Lue, J.W.
- Type of Report and Period Covered Note:
- Final; 02/01/1994 - 02/01/1994
- Funding Information:
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