Investigation On Magnetic Field And Interaction Between Magnetic Refrigerants & Magnetic Field For Room Temperature Magnetic Refrigeration

In this thesis, three key-technologies of magnetic refrigeration, as magnetic refrigerants, magnetic fields and heat cycles, are reviewed and magnetic field for room-temperature magnetic refrigeration is mainly researched. Firstly, a magnetic refrigeration apparatus as well as its experiments are introduced, and permanent magnetic field in this apparatus as well as some factors of influencing on magnetic field are analyzed. Secondly, advanced method is applied to design high field strength permanent magnetic circuits for reciprocal and rotary room-temperature magnetic refrigerators. Thirdly, interaction between magnetic refrigerants and magnetic field is investigated, and its influence on magnetic refrigerator is analyzed. Finally, in order to obtain the parameter of adiabatic temperature change of magnetic refrigerants, one equipment for direct measurement of magnetocaloric effect has been built and pulsed magnet in this equipment has been designed and tested. The main creative results and new progesses in this thesis are presented as follows:1. A room-temperature magnetic refrigeration apparatus is designed and built. The result shows : 1) in this room-temperature magnetic refrigeration apparatus, 4K span temperature has been obtained and the idea of cascade, obtaining large temperature difference through superimposing small temperature difference, is achieved, 2)It is beneficial for heat exchange to use fluid transferring heat and sheeting magnetic refrigerants, and 3)it is beneficial for elevating temperature span to distribute magnetic refrigerants by asymmetry. In this apparatus, the performance of transferring heat is better than it in R.Aoki's apparatus and temperature span is larger. In addition, according to practical situation of magnetic refrigeration, the factors of influencing on magnetic field are analyzed. These works provide technologic basis for designing magnetic refrigerators and are important inengineering.2. Rotation theorem and focusing magnetic field is applied to design high field strength permanent magnetic circuits for reciprocal and rotary room-temperature magnetic refrigerators. The magnetic field strength in the center of work space is up to 1.86Tand 1.971; respectively the level of desigi is advanced in the world.3. For the first time, Interaction between magnetic refrigerants & magnetic field and its influence on magnetic refrigeration are comprehensively analyzed, which has theoretical significance to design magnetic refrigerants' figuration and magnetic refrigerators'configuration & arrangement, and actual significance to effectively use magnetic field and increase refrigrating efficiency.4. Pulsed magnet with LN2 cooling, where magnetic field can been adjusted from 0 to 2.2T, for direct measuring magnetocaloric effect has been designed by using different methods, and one equipment for direct measuring magnetocaloric effect has been designed and built. The results show that this equipment has the merits of simpleness & economy and the adiabatic temperature change of magnetic refrigerants is conveniently and truly measured by using this equipment. This work can provide comprehensive data for designing room-temperature magnetic refrigerators and enriches method of investigating room-temperature magnetic refrigeration. Patent of this equipment is applied for and a related paper is indexed in SCI...