Design Of An Electromagnetic Heater For Tire Vulcanization Gas And Analysis Of Its Thermal And Flow Fields Characteristics

The vulcanization process of traditional rubber tires uses steam heating,which consumes a lot of energy.In this paper,an electromagnetic induction heater is proposed,that is,an electromagnetic induction heater is added to the sulfurized nitrogen pipeline to heat the nitrogen in the pipeline.The paper takes the electromagnetic induction heater of tire vulcanized gas as the research object,analyzes the influence law of different induction heating process parameters on the heater,nitrogen temperature and its distribution,and obtains the flow heat transfer characteristics of nitrogen flow field in the cylinder.Firstly,according to the requirements of the design task,the length of the heater pipeline model is 3m and the inner diameter is 50 mm by using the formula of forced convection in the pipe.Through consulting the data,it is determined that the heater tube body is made of stainless steel,and the outer insulation layer is made of ceramic fiber cotton.The induction heating coil is designed,and the drawing software is used for modeling.The three dimensional models of the heater with the length of 3m and 0.5m are drawn respectively to prepare for the subsequent analysis of the characteristics of temperature field and flow field.A mathematical model of electromagnetic field was established based on the electromagnetic theory.Due to the axial symmetry of the heater model,a 1/6 model was established to reduce the calculation amount.The magnetic field analysis results were obtained by setting initial conditions and boundary conditions,meshing the model and applying loads.Under the induction parameters of 300 A current,8k Hz frequency,20 turns of coil and 10 mm distance between coil and tube wall,the magnetic field intensity,magnetic flux distribution,eddy current density and eddy current loss were analyzed.The magnetic field intensity meets the range of 0.01～1.The magnetic field line passes through the inside of the coil and returns along the outside to form a closed loop.The distribution of the magnetic field confirms that the design shape of the electromagnetic heater is reasonable.The magnetic field analysis results show that the magnetic field intensity and eddy current density in the center area of the outer wall of the heater are high,and the eddy current loss is also high.The magnetic-thermal coupling model was established by simulation analysis software,and the temperature field distribution of the outer wall of the heater was studied at the heating time of 350 s.The results show that under this induction parameter,the overall temperature of the outer wall of the heater model reaches the temperature required by nitrogen vulcanization,and the axial temperature difference of the heater is also uniform,with the maximum temperature difference of 12℃.By analyzing the distribution of temperature field when the current is 250 A,350A and the frequency is3 k Hz and 15 k Hz respectively,the temperature of special points is recorded and the broken line chart is drawn to compare the temperature uniformity of the heater model under different induction heating parameters.It is concluded that in a certain range,the larger the coil current and frequency,the higher the heating temperature.Finally,when the current is 300 A,the frequency is 8k Hz,the coil is 20 turns,and the distance between the coil and the pipeline is 10 mm,the heating effect is the best.The overall temperature of the outer wall of the heater can reach 199-211℃,which has reached the temperature required for nitrogen vulcanization.Taking an electromagnetic heater with a length of 3m and an inner diameter of50 mm as the research object,the temperature of nitrogen at the inlet of the heater was set as 20℃ and the initial flow rate as 3.11m/s under the induction parameters with a current of 300 A and a frequency of 8k Hz.The temperature distribution of the heater model and the flow rate and temperature of nitrogen flowing through the heater pipeline were analyzed.The temperature distribution of nitrogen in the heater pipeline is studied.The results show that the overall velocity of nitrogen changes evenly,and the temperature of nitrogen increases gradually from the inlet end to the outlet end.Due to heat conduction,the temperature of nitrogen closer to the inner wall of the pipe is higher.By marking special points,the minimum temperature of nitrogen at the outlet of the heater at 600 s is determined to be 182℃,which meets the requirement of vulcanization,which proves the feasibility of the heater design.