Determination of heat transfer parameters in the mechanical heat switch for a refrigerating machine with magnetocaloric effect

The process of heat transfer in a mechanical thermal switch, which is an integral part of a solid-state magnetic refrigerator with a working body made of an alloy with a magnetocaloric effect (MCE), for example, DyNi$_2$, is investigated theoretically. In the working cycle of the refrigerator, the alloy can be a source of heat or a heat sink, respectively, during adiabatic magnetization or demagnetization. In the thermal key, the DyNi$_2$ alloy disk and the annealed copper disk are being in contact. These discs are fixed with a textolite holder along the periphery. With the help of an actuator, a working body in the form of a DyNi$_2$ alloy disk is adiabatically introduced and removed into the magnetic field of a superconducting magnet with an induction of up to 10 T. A numerical experiment was used to assess the degree of adiabaticity when fastened with a textolite holder. Also, by means of a numerical experiment, the amount of heat transferred from the working body DyNi$_2$ to the copper disks of the thermal switch is investigated. As a result of the calculation, the value of the time is required to transfer the heat as a result of the MCE from the DyNi$_2$ alloy to the copper disk was obtained, which was about 0.065 sec.