Research On Dual-rotor Electric-mechanical-thermal Transducer Based On Rotational Electromagnetic Theory

With electric-mechanical-thermal transducer, new heating supply system is an energy-saving and environmental friendly technology. Through the rotating coupling magnetic field, electric-mechanical-thermal transducer can convert input mechanical energy produced by wind turbines, hydraulic turbine and motor, into various forms of heat energy, including eddy current loss, hysteresis loss, secondary induction current loss, mechanical stray loss, and take water as heat transfer medium. Meanwhile, the rotating magnetic field and temperature field in electric-mechanical-thermal transducer will contribute to softening water medium. It is necessary to improve the thermal power, the heat transfer efficiency and the magnetization of the transducer at low speed, for making it easier to use the clean energy such as wind, water. Because of its structure design, perfect theoretical models, fluid flow and heat transfer calculation, and softening mechanism analysis, the study of electric-mechanical-thermal transducer will provide a powerful research foundation for further engineering application. The main research contents include:Firstly, two novel electric-mechanical-thermal transducers are put forward, which refer to cylinder shaped structure with radial flux and disk structure with axial flux respectively, and both of them using dual-rotor with intermediate stator structure design. Based on Maxwell equations, the fundamental electromagnetic field equations for electric-mechanical-thermal transducer are established by traditional analytical method. By using the finite element method, the magnetic field and eddy current distribution of transducer with dual-rotor configuration and transducers with single rotor configuration are compared and analyzed. Results show that the transducer with dual-rotor configuration is more conductive to heat water, because it can produce heat on both sides of the stator. Meanwhile, the transducer with dual-rotor configuration is more favorable for softening water for its more homogeneous field, more magnetic flux density and long water travel in the stator. The novel electric-mechanical-thermal transducer can increase the material utilization ratio of stator and permanent magnet, with its low speed and high power characteristics, and it is easier to implement engineering application of wind, hydropower and other clean energy.Secondly, based on Coulomb’s law and the Lorentz force law, the analytical model of thermal power is established respectively for the electric-mechanical-thermal transducer with radial flux and the one with axial flux. In the model, the boundary condition that the current density at the edge of the stator conductor is 0, is considered by constructing virtual charge image, which make more accurate results. The influence of flux and skin effect is also considered in the thermal power model of electric-mechanicalthermal transducer with radial flux. The mathematical model is characterized as a clear structure parameter relationship and fast operation, without complicated numerical calculation. Validation of the finite element analysis results show that the mathematical model of thermal power for novel electric-mechanical-thermal transducer can accurately give the relationship between heat power and speed in a certain speed range.Thirdly, the mathematical model of fluid flow and heat transfer is established, the basic assumption and boundary conditions are given, and the air gap heat conduction coefficient and the surface heat dissipation coefficient are determined. Using the finite volume method, coupling calculation of fluid flow and heat transfer inside the electricmechanical-thermal transducer, and analysis of heating water performance are both carried on. The electric-mechanical-thermal transducer experiment platform is established, which test heating performance. The test results and numerical calculation results are proved to be consistent in certain speed range and accuracy of the numerical analysis method is confirmed. Therefore, theoretical and experimental basis will be provided for design of heat transfer and coupled computing of synthesis physical field.Finally, by using the method of molecular dynamics simulation, the effect of rotating magnetic field and temperature on micro structure and molecular dynamics of pure water is studied, and the action mechanism is explored. An electric-mechanicalthermal transducer is used to process Ca2++CO32-+HCO3- solution. By measuring the change of conductivity and turbidity of the solution, the mechanism of crystallization process of Ca CO3 affected by electric-mechanical-thermal transducer is discussed and analyzed. Thus, the above work will provide theoretical and experimental basis for the study of the equipment manufacturing and engineering application of electricmechanical-thermal transducer.