Research On The Key Parameters Of Cylindrical Cavity Impacting On Tire Microwave Vulcanization

Microwave vulcanization is a new type of rubber vulcanization,which has faster vulcanization rate and higher efficiency.Therefore,a specific microwave vulcanization device for tire is of highly practical nowadays.Many researches on resonator cavity design have been done by scholars from home and abroad,few emphasized the resonator for microwave vulcanization of tire,with only some on rectangular one.With higher quality factor,convenient tuning function,firm structure and easy processing advantages,cylinder resonator is selected as the subject for size-designing.In order to obtain cylindrical resonator type tire microwave curing equipment,the following aspects are studied tersely in the paper:1.The size and different parameters of the cylindrical resonator are calculated theoretically for the 7.50R20 internal supporter tire,from which a cylindrical resonator having a number of modes greater than or equal to 9 and a degenerate ratio of 0 is selected.10 sets of cylindrical resonator cavities were determined,and then the numerical simulation of the tire microwave vulcanization process in the selected 10 sets of cylindrical resonators was carried out.The research conclusions as follows:(1)The higher the microwave utilization rate is,the higher the average temperature of the tire body is.The average temperature of the body and the utilization ratio of microwave showed a good linear function.(2)In the radius of 652 mm,height of 470 mm cylindrical resonator,the maximum temperature difference between the cylindrical cavity is the smallest,and the tire heating is the most uniform,and the heating effect is the best.2.The effect of the number and position of the waveguide on the microwave vulcanization of tire was studied.The research conclusions as follows:(1)With the waveguide angle(upper and lower sides of the distribution)from 15 degrees to 90 degrees,the uniformity of microwave vulcanization of tire gradually increases,and the maximum temperature difference of cylindrical cavity reduces,and the microwave heating time decreases.(2)The main heating parts of the double-waveguide resonator(Side and the upper and lower sides of the distribution)with different waveguides are the same,which is the middle part of the tire tread and the middle part of the sidewall near the upper waveguide of the resonator.In the process of waveguide angle from 15 degrees to 90 degrees,the microwave heating tire uniformity is getting better and better.The microwave heating time when the average temperature of the tire body is 100 ? is opposite to that of the maximum temperature difference.With the increase of the angle of the waveguide from 15 degrees to 90 degrees,the maximum temperature difference is decreasing.When the wave angle is 90 degrees,there is a small fluctuation;microwave heating time with the waveguide angle from 15 degrees to 90 degrees is on the rise.(3)In the three-waveguide cylindrical resonator of different angle,the main heating for the tire tread in the middle part of the temperature is mainly between 100 ? to 120 ?.The rest of the tire is relatively homogeneous and the temperature is between 80? and 100?.The microwave heating uniformity of the three-waveguide cylindrical resonator with different waveguide angle is roughly the same.(4)The microwave wave vulcanization's effect of the four-wave cylindrical resonator with the angle of 210 degrees is better than that of other structures(Single waveguide cylindrical resonator,double waveguide cylindrical resonator,three waveguide cylindrical resonator,five waveguide cylindrical resonator).Therefore,it is established as a basic cylindrical resonator model suitable for tire microwave curing.3.The effect of the frequency and power of the cylindrical cavity on the microwave curing of the cylindrical cavity was discussed.The research conclusions as follows:(1)When the microwave frequency from 890 MHz to 940 MHz within the range of the tire vulcanization,the microwave frequency of 915 MHz four-wave cylindrical resonator(waveguide angle of 210 degrees)within the maximum tire temperature difference,microwave heating time is short,microwave utilization is relatively large,and the best heating uniformity.The optimum frequency for microwave vulcanization is 915 MHz.(2)In the heating process of the rubber ring,the main heating parts of the cylindrical resonator are not affected by the microwave frequency.The microwave frequency has a certain influence on the microwave heating uniformity of the cylindrical resonator.The average temperature and maximum temperature difference of the rubber ring are also affected by the frequency,and the influence is related to the structure of the cylindrical resonator.(3)In conditions of constant microwave energy,the average temperature of the rubber ring in the cylindrical resonator is not affected by the microwave output power,that is,the microwave utilization of the cylindrical resonator is not affected by the microwave output power,and the main heating parts are not affected by power.However,with the increase of the microwave output power,the maximum temperature difference of the rubber ring in the cylindrical resonator gradually increases,and the uniformity gradually becomes worse.(4)For the waveguide angle of 210 degrees four-waveguide cylindrical resonator tire microwave curing,the lower the microwave power is,the smaller the tire temperature difference is.When microwave output power reaches 2k W,the tire maximum temperature difference is 10 ?,with the traditional curing method of the maximum temperature difference.Its maximum temperature difference is consistent with the traditional vulcanization method.Therefore,the optimal power of the microwave vulcanization of the four-wave cylindrical resonator tire with the angle of 210 degrees is determined to be 2kW.