Simulation And Test Of "LanTian" Microwave Chemical Reactor

Microwave chemistry is one of the fastest growing scientific fields. Microwave chemical reactor plays an important role in microwave chemical engineering. Distribution of the electromagnetic field and the temperature distribution in resonant cavity can guide the design and improvement of the microwave chemical reactor. Improving the uniformity of the electromagnetic field and the temperature distribution can reduce the number of wasted products in chemical industry. However, it is difficult to measure the distribution of the electromagnetic field and the temperature inside the reactor in practice. Some sensors are necessary in the electromagnetic field. However, usually, these sensors will inevitably change the distribution of the electromagnetic field and the temperature distribution. As a result, the measurement of the distribution of the electromagnetic field and the temperature is not exact. Because the sensors in the electromagnetic field are large, the temperature of the micro hot spot cannot be measured. Therefore, we urgently need a good method to measure the distribution of the electromagnetic field and the temperature inside the microwave chemical reactor.With the rapidly increase of the computer speed and the improvement of numerical calculation method, it is possible to calculate the distribution of the electromagnetic field and the temperature under the complex condition. In this thesis, the FDTD (Finite-Difference Time-Domain) method is used to calculate the coupled Maxwell's equations and Fourier's heat transport equation. By the aid of this method,the distribution of the electromagnetic field and the temperature can be calculated. In order to solve the coupled Maxwell's equations and Fourier's heat transport equation, the Yee's grid is used. Because the solution is dispersive medium, the permittivity of the solution varies with the temperature. The calculation procedures of the temperature follow the iterative steps: 1. electromagnetic field, 2. power density, 3. temperature rising, 4. permittivity update, 5. electromagnetic field. In this way, two microwave chemical reactors are studied. One is high power microwave chemical reactor with two general magnetrons. The distribution of electromagnetic field inside the microwave chemical reactor is uniform and is in good agreement with the measured results. Another is general microwave oven with only one general magnetron, which is used to heat the reaction to produce CaSO4. The calculated distribution of electromagnetic field in the oven and the temperature distribution in the solution are not uniform, but are in good agreement with the calculated results obtained from FEM (Finite-Element Method) method and the measured results respectively.Based on the above results we can draw a conclusion that the designed "LanTian" microwave chemical reactor is satisfied in the application of microwave chemistry.