“蓝田”微波化学反应器数值模拟与实验
|
摘要
微波化学是研究微波在化学中应用的一门新兴的前沿交叉学科,而微波化学反应器作为微波发生和作用的器件,则是整个微波化学反应系统中的关键部位,掌握反应器内部的电磁场分布情况和被加热物质内部的温度分布情况就可以很好的指导微波化学反应器的设计与改造,可以控制微波化学反应的速度,改善其内部电磁场分布,使之形成较均匀的电磁场分布和温度分布,防止由于物质的局部过热而导致废品率的升高,由此可以提高化工产品的成品率与转化率。但在实际的应用中,对于谐振腔内部的电磁场分布和温度分布的测量是比较困难的,需要将多个感应探头放置于反应场中进行感应测量,而感应器本身的介入对电磁场分布和温度分布就产生了改变,并且宏观的感应器是不可能测试出微观中存在的局部点的过热现象。因此,寻找一种快捷、高效、准确的反映微波化学反应器内部电磁场分布和温度分布情况的方法就成为了化工界面临的一个重要的问题。
随着计算机运算速度的飞跃提升和各种数值计算方法的不断改进与完善,用计算机来数值模拟复杂环境下的电磁场分布和温度分布就成为了可能。本文就是采用时域有限差分方法(FDTD:Finite-Difference Time-Domain)求解Maxwell方程与热传导方程(Fourier方程)的耦合来计算微波化学反应器内部的电磁场分布和温度分布。为了实现Maxwell方程与热传导方程二者的耦合求解,在空间上,使求解Maxwell方程而划分的Yee氏网格与求解热传导方程而划分的有限容积网格在体积和界面上重合,从而实现空间步长上的耦合;在时间上,
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.
随着计算机运算速度的飞跃提升和各种数值计算方法的不断改进与完善,用计算机来数值模拟复杂环境下的电磁场分布和温度分布就成为了可能。本文就是采用时域有限差分方法(FDTD:Finite-Difference Time-Domain)求解Maxwell方程与热传导方程(Fourier方程)的耦合来计算微波化学反应器内部的电磁场分布和温度分布。为了实现Maxwell方程与热传导方程二者的耦合求解,在空间上,使求解Maxwell方程而划分的Yee氏网格与求解热传导方程而划分的有限容积网格在体积和界面上重合,从而实现空间步长上的耦合;在时间上,
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.
引文
[1] 金钦汉,戴树珊,黄卡玛,《微波化学》,北京:科学出版社
[2] Stuerga D. A. C. and Gaillard P., Micwave Athermal Effects in Chemistry: A Myth's Autopsy-part Ⅰ: Historical Background and Fundamentals of Wave-matter Interaction, Journal of Microwave Power and Electromagnetic Energy, 1996, 31(2): 87-100.
[3] Stuerga D. A. C. and Gaillard P., Micwave Athermal Effects in Chemistry: A Myth's Autopsy-part Ⅱ: Orienting Effects and Thermodynamic Consequences of Electric Field, Journal of Microwave Power and Electromagnetic Energy, 1996, 31(2): 101-114.
[4] 黄卡玛,杨晓庆,微波化学非热效应研究进展,第五届全国微波化学会议特邀报告,武汉。
[5] A. Whiter. D. P. mings, The application of microwave heating to chemical syntheses of Microwave Power and Electromagnetic Engergy. 1994; 29(4): 195-219.
[6] M. Sundherg P. O. Risman P-S Kildal and T. Ohlsson Analysis And Design Of It dustrial Mierowave Ovens Using The Finite Difference Tune Domain Method JOURNAL OF MICROWAVE POWER AND ELECTROMAGNETIC ENERGY Vol. 31 No.3, 1996: 142-156
[7] H. C. Reader and T. Y. Chow Ting Chan Experimental and Numerical Field Studies In Loaded Multimode And Single Mode Cavities JOURNAL OF MICROWAVE POWER AND ELECTROMAGNETIC ENERGY Vol, 33 No. 2, 1998, p103-I11
[8] S. TADA R. echigo and H. yoshida Numerical Analysis of Electromagnetic Wave in a Partially Loaded Microwave Applicator Int J. Heat Mass Transfer Vol. 41 No. 4 p709-718
[9] K. Iwabuchi T. kuhota and T. Kashiwa Analysis Of Electromagnetic Fields In a Mass-Produced Microwave Oven Using The Finite-Difference Time-Domain Method Joururnal Of Microwave Power and Electromagnetic Energy Vol. 31 No. 3 1996 p188-196
[10] Francois Torres and Bernard Jecko Complete FDTD Analysis Of Microwave Heating Processes In Frequency-Dependent and Temperature-Dependent Media IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES Vol. 45 No. 1 1997 p108-115
[11] M. Suhirats, M. F. Iskander M. J. White and J. O. Kiggan, Jr. FDTD Simulation Of Microwave Sintering In Large Multimode Cavities Journal Of Microwave Power and Electromagnetic Energy Vol. 32 No. 3 1997 p161-170
[12] F. Liu I. Turner E. Siores and P. Groombridge A Numerical and Experimental Investigation Of The Microwave Heating Of Polymer Materials Inside A Ridge Waveguide Journal Of Microwave Power and Electromagnetic Energy Vol. 31 No. 2 1996 p71-82
[13] Lizhuang Ma, Dominique-Lynda Paulet Experimental Validation Of a Combined Electromagnetic and Thermal FDTD Model Of A Mcrowave Heating Process IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES Vol. 43 No. 11 1995 p2565-2572
[14] 闫丽萍,黄卡玛,刘长军,杜国宏 微波加热FDTD模拟中时间压缩因子的研究 四川大学学报(自然科学版)2003(2):395-398
[15] 刘长军,黄卡玛,胡仲霞,赵翔,袁渊,陈星,化学反应对微波非线性响应的实验研究和数值模拟,微波学报,2000年,16(2),165-171
[16] 闫丽萍、黄卡玛、刘长军、陈星、赵翔,微波对流体加热过程的数值分析,电子学报,2003,(31)5,667-670
[17] Barlow Stephen and Marder Seth R., Single-mode microwave synthesis in organic materials chemistry, Advanced Functional Materials, 2003, 13(7), 517-518
[18] Buchta R., Boling G, Sellberg F., and Sigurd D., Microwave heating for VLSI processing, Conference Proceedings-European Microwave Conference, 1992, 1(22), 34-46
[19] Yang Jae Ho, Song Kun Woo, Lee Yong Woo, Kim Jong Heon, Kang Ki Won, Kim Keon Sik and Jung Youn Ho, Microwave process for sintering of uranium dioxide, Journal of Nuclear Materials, 2004, 325(2-3), 210-216
[20] White Mikel J., Dillon Steven E, Iskander Magdy F., and Kimrey Hal D., Finite-difference time-domain simulation of microwave sintering in a variable-frequency multimode cavity, Materials Research Society Symposium Proceedings, v 430, Microwave Processing of Materials V, 1996, 487-492
[21] Travelling-wave type microwave chemical reactor with slot wave guide CN1250685
[22] An improved heating process for chemical reaction vessels employing microwave energy EP0680243
[23] High-efficiency microwave radical reactor JP2002136864
[24] Microwave applicator and plasma reactor using the same EP0564359
[25] Batch microwave reactor US5, 932, 075
[26] 一种常压微波放电及其在氮氧化合物脱除中的应用CN-00110497
[27] 行波式槽波导微波化学反应装置CN-99114426
[28] 新型微波连续反应器CN-99217568
[29] 多功能工业用微波能加热反应装置CN-96207039
[30] Raner Kevin D., Strauss Christopher R., Trainor Robert W., and Thorn John S., New microwave reactor for batchwise organic synthesis, Journal of Organic Chemistry, 1995, 60(8), 2456
[31] 孙嫚等 适用于化学合成的微波炉的改造与性能测定,微波学报,1998;14(4):377-382
[32] 何翔 黄卡玛 曾晓勇 一种微波化学加热装置的设计分析与实验测试,微波学报,2005,(3),231-235;
[33] H. Zhao, LW. Turner. An analysis of the finite-differenc time-domain method for modeling the microwave heating of dielectric materials within a three-dimensional cavity system. Journal of Microwave power and Electromagnetic Energy, 1996, 31(4): 194-213
[34] 陶文铨 数值传热 学西安交通大学出版社 1988,10-27
[35] K. S. Yee, Numerical solution of initial boundary value problem involving Maxwell's equations in isotropic media, IEEE Trans. Ante. Prop., 1966, 14, 302-307
[36] 葛德彪,闫玉波,电磁波时域有限差分方法,西安电子科技大学出版社,2002年4月,36-45
[37] Berenger J P, A perfectly matched layer for the absorption of Electromagnetic waves, J. Comput. Phys., 1994, 114(2), 185-200
[38] Berenger J P, A perfectly matched layer for the FDTD solution of wave -structure interaction problem, IEEE Trans. Antennas Propogat., 1996, AP-44(1), 110-117
[39] Stephen D. Gedney, An anisotropic perfectly matched layer-absorbing medium for the truncation of FDTD Lattices, IEEE Trans. Antennas Prop., 1996, AP-44(12), 1630-1639
[40] F. Torres and B. Jecko, IEEE Trans. on MTT, 1997, 45 (1), 108.
[41] 高本庆,陈金元,色散媒质中电磁场的时域有限差分算法,《中国科学》(A辑),1994,24(5),538-545
[42] 黄瑞祥等,微波炉使用维修300问,杭州:浙江科学技术出版社,1999.37-38
[43] 赵春晖,杨莘元,现代微波技术基础,哈尔滨:哈尔滨工程大学出版社,2000:140-145
[44] 王子宇,微波技术基础,北京:北京大学出版社,2003:172-175
[45] 古天乐,黄志洵,截止波导与截止衰减器,北京:人民邮电出版社,1977:94-120 I
[46] 张兆镗,钟若青,微波加热技术基础,北京:电子工业出版社,1988:280-290
[47] Kenneth. R. Demorest,著,工程电磁学,北京,科学出版社 2003,509-562
[48] 闫丽萍等,微波炉功率、均匀性及安全性的测定,微波学报,1996;12(2):159-162
[2] Stuerga D. A. C. and Gaillard P., Micwave Athermal Effects in Chemistry: A Myth's Autopsy-part Ⅰ: Historical Background and Fundamentals of Wave-matter Interaction, Journal of Microwave Power and Electromagnetic Energy, 1996, 31(2): 87-100.
[3] Stuerga D. A. C. and Gaillard P., Micwave Athermal Effects in Chemistry: A Myth's Autopsy-part Ⅱ: Orienting Effects and Thermodynamic Consequences of Electric Field, Journal of Microwave Power and Electromagnetic Energy, 1996, 31(2): 101-114.
[4] 黄卡玛,杨晓庆,微波化学非热效应研究进展,第五届全国微波化学会议特邀报告,武汉。
[5] A. Whiter. D. P. mings, The application of microwave heating to chemical syntheses of Microwave Power and Electromagnetic Engergy. 1994; 29(4): 195-219.
[6] M. Sundherg P. O. Risman P-S Kildal and T. Ohlsson Analysis And Design Of It dustrial Mierowave Ovens Using The Finite Difference Tune Domain Method JOURNAL OF MICROWAVE POWER AND ELECTROMAGNETIC ENERGY Vol. 31 No.3, 1996: 142-156
[7] H. C. Reader and T. Y. Chow Ting Chan Experimental and Numerical Field Studies In Loaded Multimode And Single Mode Cavities JOURNAL OF MICROWAVE POWER AND ELECTROMAGNETIC ENERGY Vol, 33 No. 2, 1998, p103-I11
[8] S. TADA R. echigo and H. yoshida Numerical Analysis of Electromagnetic Wave in a Partially Loaded Microwave Applicator Int J. Heat Mass Transfer Vol. 41 No. 4 p709-718
[9] K. Iwabuchi T. kuhota and T. Kashiwa Analysis Of Electromagnetic Fields In a Mass-Produced Microwave Oven Using The Finite-Difference Time-Domain Method Joururnal Of Microwave Power and Electromagnetic Energy Vol. 31 No. 3 1996 p188-196
[10] Francois Torres and Bernard Jecko Complete FDTD Analysis Of Microwave Heating Processes In Frequency-Dependent and Temperature-Dependent Media IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES Vol. 45 No. 1 1997 p108-115
[11] M. Suhirats, M. F. Iskander M. J. White and J. O. Kiggan, Jr. FDTD Simulation Of Microwave Sintering In Large Multimode Cavities Journal Of Microwave Power and Electromagnetic Energy Vol. 32 No. 3 1997 p161-170
[12] F. Liu I. Turner E. Siores and P. Groombridge A Numerical and Experimental Investigation Of The Microwave Heating Of Polymer Materials Inside A Ridge Waveguide Journal Of Microwave Power and Electromagnetic Energy Vol. 31 No. 2 1996 p71-82
[13] Lizhuang Ma, Dominique-Lynda Paulet Experimental Validation Of a Combined Electromagnetic and Thermal FDTD Model Of A Mcrowave Heating Process IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES Vol. 43 No. 11 1995 p2565-2572
[14] 闫丽萍,黄卡玛,刘长军,杜国宏 微波加热FDTD模拟中时间压缩因子的研究 四川大学学报(自然科学版)2003(2):395-398
[15] 刘长军,黄卡玛,胡仲霞,赵翔,袁渊,陈星,化学反应对微波非线性响应的实验研究和数值模拟,微波学报,2000年,16(2),165-171
[16] 闫丽萍、黄卡玛、刘长军、陈星、赵翔,微波对流体加热过程的数值分析,电子学报,2003,(31)5,667-670
[17] Barlow Stephen and Marder Seth R., Single-mode microwave synthesis in organic materials chemistry, Advanced Functional Materials, 2003, 13(7), 517-518
[18] Buchta R., Boling G, Sellberg F., and Sigurd D., Microwave heating for VLSI processing, Conference Proceedings-European Microwave Conference, 1992, 1(22), 34-46
[19] Yang Jae Ho, Song Kun Woo, Lee Yong Woo, Kim Jong Heon, Kang Ki Won, Kim Keon Sik and Jung Youn Ho, Microwave process for sintering of uranium dioxide, Journal of Nuclear Materials, 2004, 325(2-3), 210-216
[20] White Mikel J., Dillon Steven E, Iskander Magdy F., and Kimrey Hal D., Finite-difference time-domain simulation of microwave sintering in a variable-frequency multimode cavity, Materials Research Society Symposium Proceedings, v 430, Microwave Processing of Materials V, 1996, 487-492
[21] Travelling-wave type microwave chemical reactor with slot wave guide CN1250685
[22] An improved heating process for chemical reaction vessels employing microwave energy EP0680243
[23] High-efficiency microwave radical reactor JP2002136864
[24] Microwave applicator and plasma reactor using the same EP0564359
[25] Batch microwave reactor US5, 932, 075
[26] 一种常压微波放电及其在氮氧化合物脱除中的应用CN-00110497
[27] 行波式槽波导微波化学反应装置CN-99114426
[28] 新型微波连续反应器CN-99217568
[29] 多功能工业用微波能加热反应装置CN-96207039
[30] Raner Kevin D., Strauss Christopher R., Trainor Robert W., and Thorn John S., New microwave reactor for batchwise organic synthesis, Journal of Organic Chemistry, 1995, 60(8), 2456
[31] 孙嫚等 适用于化学合成的微波炉的改造与性能测定,微波学报,1998;14(4):377-382
[32] 何翔 黄卡玛 曾晓勇 一种微波化学加热装置的设计分析与实验测试,微波学报,2005,(3),231-235;
[33] H. Zhao, LW. Turner. An analysis of the finite-differenc time-domain method for modeling the microwave heating of dielectric materials within a three-dimensional cavity system. Journal of Microwave power and Electromagnetic Energy, 1996, 31(4): 194-213
[34] 陶文铨 数值传热 学西安交通大学出版社 1988,10-27
[35] K. S. Yee, Numerical solution of initial boundary value problem involving Maxwell's equations in isotropic media, IEEE Trans. Ante. Prop., 1966, 14, 302-307
[36] 葛德彪,闫玉波,电磁波时域有限差分方法,西安电子科技大学出版社,2002年4月,36-45
[37] Berenger J P, A perfectly matched layer for the absorption of Electromagnetic waves, J. Comput. Phys., 1994, 114(2), 185-200
[38] Berenger J P, A perfectly matched layer for the FDTD solution of wave -structure interaction problem, IEEE Trans. Antennas Propogat., 1996, AP-44(1), 110-117
[39] Stephen D. Gedney, An anisotropic perfectly matched layer-absorbing medium for the truncation of FDTD Lattices, IEEE Trans. Antennas Prop., 1996, AP-44(12), 1630-1639
[40] F. Torres and B. Jecko, IEEE Trans. on MTT, 1997, 45 (1), 108.
[41] 高本庆,陈金元,色散媒质中电磁场的时域有限差分算法,《中国科学》(A辑),1994,24(5),538-545
[42] 黄瑞祥等,微波炉使用维修300问,杭州:浙江科学技术出版社,1999.37-38
[43] 赵春晖,杨莘元,现代微波技术基础,哈尔滨:哈尔滨工程大学出版社,2000:140-145
[44] 王子宇,微波技术基础,北京:北京大学出版社,2003:172-175
[45] 古天乐,黄志洵,截止波导与截止衰减器,北京:人民邮电出版社,1977:94-120 I
[46] 张兆镗,钟若青,微波加热技术基础,北京:电子工业出版社,1988:280-290
[47] Kenneth. R. Demorest,著,工程电磁学,北京,科学出版社 2003,509-562
[48] 闫丽萍等,微波炉功率、均匀性及安全性的测定,微波学报,1996;12(2):159-162