Heat Exchangers From Metal-Bonded La(Fe,Mn,Si)13H x Powder
| Autor: | Alexey Yu. Karpenkov, Iliya Radulov, Oliver Gutfleisch, Konstantin P. Skokov, Tobias Braun, Marius Specht, Dmitriy Yu. Karpenkov |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Packed bed Materials science Alloy 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials Coating 0103 physical sciences Regenerative heat exchanger Heat transfer Heat exchanger engineering Magnetic refrigeration Electrical and Electronic Engineering Composite material 0210 nano-technology Eutectic system |
| Zdroj: | IEEE Transactions on Magnetics. 53:1-7 |
| ISSN: | 1941-0069 0018-9464 |
| Popis: | Hydrogenated La(Fe,Mn,Si)13-based alloys have an excellent magnetocaloric properties, but poor mechanical and chemical stability. This hinders their direct machining and implementation in an active magnetic regenerator (AMR). In this paper, we show how machinability and corrosion protection of the particles can be improved by a hot-dip coating. To avoid the loss of hydrogen during the coating process, a low melting temperature eutectic Bi–Sn–In alloy was selected as a metal binder. The coated particles were used to build a packed bed regenerator as an array of fixed particles, avoiding such negative effects as sedimentation, segregation, and channel deformation. Similarity theory, combined with unsteady heat transfer approach was applied in order to calculate the optimal operation frequency and to estimate the maximal cooling power of the magnetocaloric regenerators. Two different geometries of heat exchangers were theoretically compared: stacked flat plate/channel structure and packed bed of equidimensional spherical particles. It is shown that, operating at low frequency, the same amount of magnetocaloric material can expel bigger amount of heat, when formed as packed bed heat exchangers. The metal-bonded packed bed regenerator made from La(Fe,Mn,Si)13H x powder was tested in a home-build versatile testing device in a magnetic field change of 10 kOe. The maximal achievable temperature span as a function of both parameters—hot end temperature and length of regenerator—was explored. The largest thermal span of 8 K was produced by the regenerator with 40 mm length. |
| Databáze: | OpenAIRE |
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