TY - JOUR
T1 - Passive characterization and active testing of epoxy bonded regenerators for room temperature magnetic refrigeration
AU - Lei, Tian
AU - Navickaité, Kristina
AU - Engelbrecht, Kurt
AU - Barcza, Alexander
AU - Vieyra, Hugo
AU - Nielsen, Kaspar Kirstein
AU - Bahl, Christian
PY - 2017
Y1 - 2017
N2 - Epoxy bonded regenerators of both spherical and irregular La(Fe,Mn,Si)13Hy
particles have been developed aiming at increasing the mechanical
strength of active magnetic regenerators (AMR) loaded with brittle
magnetocaloric materials and improving the flexibility of shaping the
regenerator geometry. Although the magnetocaloric properties of these
materials are well studied, the flow and heat transfer characteristics
of the epoxy bonded regenerators have seldom been investigated. This
paper presents a test apparatus that passively characterizes
regenerators using a liquid heat transfer fluid with an oscillating flow
at low Reynolds numbers, simulating the hydraulic working conditions in
AMRs. Dimensionless parameters, including friction factor,
effectiveness and overall Nusselt number, are presented for the epoxy
bonded La(Fe,Mn,Si)13Hy regenerators and reference
packed particle beds. Moreover, a five-layer AMR based on spherical
particles is tested actively in a small reciprocating magnetic
refrigerator, achieving a no-load temperature span of 16.8 °C using about 143 g of epoxy-bonded La(Fe,Mn,Si)13Hy
materials. Simulations based on a one-dimensional (1D) AMR model are
also implemented to validate and analyze the results from the active
test.
AB - Epoxy bonded regenerators of both spherical and irregular La(Fe,Mn,Si)13Hy
particles have been developed aiming at increasing the mechanical
strength of active magnetic regenerators (AMR) loaded with brittle
magnetocaloric materials and improving the flexibility of shaping the
regenerator geometry. Although the magnetocaloric properties of these
materials are well studied, the flow and heat transfer characteristics
of the epoxy bonded regenerators have seldom been investigated. This
paper presents a test apparatus that passively characterizes
regenerators using a liquid heat transfer fluid with an oscillating flow
at low Reynolds numbers, simulating the hydraulic working conditions in
AMRs. Dimensionless parameters, including friction factor,
effectiveness and overall Nusselt number, are presented for the epoxy
bonded La(Fe,Mn,Si)13Hy regenerators and reference
packed particle beds. Moreover, a five-layer AMR based on spherical
particles is tested actively in a small reciprocating magnetic
refrigerator, achieving a no-load temperature span of 16.8 °C using about 143 g of epoxy-bonded La(Fe,Mn,Si)13Hy
materials. Simulations based on a one-dimensional (1D) AMR model are
also implemented to validate and analyze the results from the active
test.
KW - Magnetic refrigeration
KW - Active magnetic refrigerator
KW - Epoxy bonded regenerator
KW - Heat transfer
KW - Friction factor
U2 - 10.1016/j.applthermaleng.2017.08.152
DO - 10.1016/j.applthermaleng.2017.08.152
M3 - Journal article
SN - 1359-4311
VL - 128
SP - 10
EP - 19
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
ER -