Special Heat Transfer Mechanisms: Active and Passive Thermal Diodes - Magnetocaloric Energy Conversion: From Theory to Applications - page 242

Fig. 6.25 An example of applying the MHD principle in magnetic refrigeration

liquid metal is incompressible, it will therefore move in an azimuth direction in all
the elements of the device. When the magnet assembly passes to the HHEX, the
liquid metal is at rest, so no ows take place (Fig. 6.25 b). When the second

pair of AMRs is being magnetized (Fig. 6.25 c), the liquid metal

fl uid fl

fl uid fl ow is

reversed by activating the second electrodes. The ows in the counter

direction. Note that this could also be done with a single MHD system and not two,
as shown in Fig. 6.25 .
The MHD can also be applied as the thermal contact diode, which uses the liquid

fl uid now fl

fl ow propelled by the Lorenz force to or from the heat sink or heat source

(Fig. 6.26 ). Note that the magnetic eld source denoted by N - S can be provided by

any kind of magnet. Of course, in this case one should nd a solution for how to

avoid the magnetization of the magnetocaloric material when this is in the process
related to its demagnetized state. Therefore, Fig. 6.26 should serve only as an
illustration and not as a solution.