基于颗粒流模型微波辅助破岩过程数值模拟
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摘要
微波辅助破岩是一种新型的破岩技术,通过微波加热预先在岩石内部产生微裂纹,然后联合其它破岩手段,可以有效提高破岩效率。以吸波的方铅矿和透波的方解石组成的岩石颗粒为研究对象,采用颗粒流程序建立了细观数值模型,对微波照射下的岩石颗粒细观物理力学应进行了模拟分析,揭示了不同微波照射条件下岩石内部温度分布与演化以及微裂纹的产生与发展的规律。研究结果表明:微波照射下,方铅矿温度明显高于方解石,岩石温度呈不均匀分布,不同矿物之间存在温差;微波照射可以使岩石在时间很短及温度较低的情况下产生微裂纹;微裂纹主要由方铅矿的热膨胀引起,微裂纹以拉伸裂纹为主,极少部分为剪切裂纹。岩石内部微裂纹的分布形态主要取决于方铅矿在岩石中的分布;微波照射时,裂纹首先产生于方铅矿周围,继而向周边的方解石内扩展,相互连通后导致岩石破裂;在消耗能量相同的情况下,微波功率越高,需要微波照射时间越短,岩石内部温差越大,产生的裂纹数量越多,破岩的效率更高。
Microwave-assisted rock-breaking is a new rock-breaking technology,which can effectively improve the rock-breaking efficiency by using microwave heating to generate micro-cracks in the rock and combining with other rock-breaking methods. Taking the rock particles composed of wave-absorbing galena and transparent calcite as the research object,a mesoscopic numerical model is established using the particle flow program,and the physical and mechanical properties of the rock particles under microwave irradiation are simulated and analyzed. The distribution and evolution of internal temperature and the formation and development of microcracks in rocks under different microwave irradiation conditions are revealed. The results show that under microwave irradiation,the temperature of galena is obviously higher than that of calcite,the temperature distribution of rock is not uniform,and there is tem-perature difference between different minerals,and micro-cracks can be produced in the case of very short time and low temperature under microwave irradiation. The microcracks are mainly caused by the thermal expansion of galena. The main microcracks are tensile cracks with very few shear cracks. The distribution of microcracks in rock is mainly determined by the distribution of galena in the rock,and when exposed to microwave irradiation,the cracks first occur around galena and then propagate into the surrounding calcite,which results in the fracture of rock after being connected with each other. In the case of the same energy consumption,the higher the microwave power is,the shorter the microwave irradiation time is,the greater the temperature difference inside the rock is,the more cracks are generated,and the rock-breaking will be more efficient.
Microwave-assisted rock-breaking is a new rock-breaking technology,which can effectively improve the rock-breaking efficiency by using microwave heating to generate micro-cracks in the rock and combining with other rock-breaking methods. Taking the rock particles composed of wave-absorbing galena and transparent calcite as the research object,a mesoscopic numerical model is established using the particle flow program,and the physical and mechanical properties of the rock particles under microwave irradiation are simulated and analyzed. The distribution and evolution of internal temperature and the formation and development of microcracks in rocks under different microwave irradiation conditions are revealed. The results show that under microwave irradiation,the temperature of galena is obviously higher than that of calcite,the temperature distribution of rock is not uniform,and there is tem-perature difference between different minerals,and micro-cracks can be produced in the case of very short time and low temperature under microwave irradiation. The microcracks are mainly caused by the thermal expansion of galena. The main microcracks are tensile cracks with very few shear cracks. The distribution of microcracks in rock is mainly determined by the distribution of galena in the rock,and when exposed to microwave irradiation,the cracks first occur around galena and then propagate into the surrounding calcite,which results in the fracture of rock after being connected with each other. In the case of the same energy consumption,the higher the microwave power is,the shorter the microwave irradiation time is,the greater the temperature difference inside the rock is,the more cracks are generated,and the rock-breaking will be more efficient.
引文
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[9]卢高明,李元辉,HASSANI Ferri,等.微波辅助机械破岩试验和理论研究进展[J].岩土工程学报,2016,38(8):1497-1506.LU Gao-ming,LI Yuan-hui,HASSANI Ferri,et al. Review of theoretical and experimental studies on mechanical rock fragmentationusing microwave-assisted approach[J]. Chinese Journal of Geotechnical Engineering,2016,38(8):1497-1506.
[10] Lu G M,Li Y H,Hassani F,et al. The influence of microwave irradiation on thermal properties of main rockforming minerals[J]. Applied Thermal Engineering,2017,112(4):1523-1532.
[11] Omran M,Fabritius T,Mattila,R. Thermally assisted liberation of high phosphorus oolitic iron ore:a comparison between microwave and conventional furnaces[J]. Powder Technology,2015,269(2):7-14.
[12] Whittles D N,Kingman S W,Reddish D J. Application of numerical modelling for prediction of the influence of power density on microwave-assisted breakage[J]. International Journal of Mineral Processing,2003,68(1):71-91.
[13] Jones D A,Kingman S W,Whittles D N,et al. Understanding microwave assisted breakage[J]. Minerals Engineering,2005,18(7):659-669.
[14] Jones D A,Kingman S W,Whittles D N,et al. The influence of microwave energy delivery method on strength reduction in ore samples[J]. Chemical Engineering and Processing(Process Intensification),2007,46(4),291-299.
[15] Hartlieb P,Leindl M,Kuchar F,et al. Damage of basalt induced by microwave irradiation[J]. Minerals Engineering,2012,31(3):82-89.
[16] Wang Y,Djordjevic N. Thermal stress FEM analysis of rock with microwave energy[J]. International Journal of Mineral Processing,2014,130(28):74-81.
[17]戴俊,秦立科.微波照射下岩石损伤细观模拟分析[J].西安科技大学学报,2014,34(6):652-655.DAI Jun,QIN Li-ke. Meso-simulation of rock damage under microwave irradiation[J]. Journal of Xi’an University of Science and Technology,2014,34(6):652-655.
[18] Like Q,Jun D. Analysis on the growth of different shapes of mineral microcracks in microwave field[J].Frattura ed Integrita Strutturale,2016,10(37):342-351.
[19] Ali A Y,Bradshaw S M. Quantifying damage around grain boundaries in microwave treated ores[J]. Chemical Engineering and Processing(Process Intensification),2009,48(11):1566-1573.
[20] Ali A Y,Bradshaw S M. Bonded-particle modelling of microwave-induced damage in ore particles[J]. Minerals Engineering,2010,23(10):780-790.
[21] Ali A Y,Bradshaw S M. Confined particle bed breakage of microwave treated and untreated ores[J]. Minerals Engineering,2011,24(14):1625-1630.
[22] Chen T T,Dutrizac J E,Hague K E,et al. The relative transparency of minerals to microwave radiation[J]. Canadian Metallurgical Quarterly,1984,23(3):349-351.
[23] Touloukian Y S,Judd W R. Physical properties of rocks and minerals[M]. New York:McGraw-Hill Book Company,1981.
[24] Bass J D. Elasticity of uvarovite and andradite garnets[J]. Journal of Geophysical Research Solid Earth,1986,91(B7):7505-7516.
[25] Clark S P. Handbook of physical constants[M]. New York:Geological Society of America,1966.
[26] QIN Li-ke,DAI Jun. Thermal stress distribution and evolution of concrete particles under microwave irradiation[J]. Journal of Engineering Science and Technology Review,2016,9(3):148-154.
[27] QIN Li-ke,DAI Jun,TENG Peng-fei. Study on the effect of microwave irradiation on rock strength[J]. Journal of Engineering Science and Technology Review,2015,8(4):91-96.
[28] QIN Li-ke,DAI Jun,ZHEN Jun-tian. Evolution of temperature and stress in rock under microwave irradiation[J]. Electronic Journal of Geotechnical Engineering,2015,20(28):13507-13516.
[29] QIN Li-ke,DAI Jun. Meso-mechanics simulation analysis of microwave-assisted mineral liberation[J]. Frattura de Integrita Strutturale,2015,9(34):543-553.
[2] Lindroth D P,Berglund W R,Morrell R J,et al. Microwave assisted drilling in hard rock[J]. Tunnels and Tunnelling,1993,25(6):24-27.
[3] Hassani F,Nekoovaght P M,Gharib N. The influence of microwave irradiation on rocks for microwave-assisted underground excavation[J]. Journal of Rock Mechanics and Geotechnical Engineering,2016,8(1):1-15.
[4] Ouellet J,Raghavan V,Radziszewski P. Exploring microwave assisted rock breakage for possible space mining applications[J]. Mining Technology,2005,115(1):34-40.
[5] Kingman S W,Rowson N A. Microwave treatment of minerals:a review[J]. Minerals Engineering,1998,11(11):1081-1087.
[6]戴俊,孟振,吴丙权.微波照射对岩石强度的影响研究[J].有色金属,2014,34(3):54-57.DAI Jun,MENG Zhen,WU Bing-quan. Study on impact of rock strength by microwave irradiation[J]. Nonferrous Metals Engineering,2014,34(3):54-57.
[7]戴俊,潘艳宾,孟振.微波照射下岩石强度弱化影响因素的试验研究[J].西安科技大学学报,2016,36(3):364-368.DAI Jun,PAN Yan-bin,MENG Zhen. Experimental study on influential factors of rock strength weakening under microwave irradiation[J]. Journal of Xi’an University of Science and Technology,2016,36(3):364-368.
[8]戴俊,师百垒,杨凡,等.微波照射下岩石损伤CT试验研究[J].西安科技大学学报,2016,36(5):616-620.DAI Jun,SHI Bai-lei,YANG Fan,et al. CT test of rock damage under the microwave irradiation[J]. Journal of Xi’an University of Science and Technology,2016,36(5):616-620.
[9]卢高明,李元辉,HASSANI Ferri,等.微波辅助机械破岩试验和理论研究进展[J].岩土工程学报,2016,38(8):1497-1506.LU Gao-ming,LI Yuan-hui,HASSANI Ferri,et al. Review of theoretical and experimental studies on mechanical rock fragmentationusing microwave-assisted approach[J]. Chinese Journal of Geotechnical Engineering,2016,38(8):1497-1506.
[10] Lu G M,Li Y H,Hassani F,et al. The influence of microwave irradiation on thermal properties of main rockforming minerals[J]. Applied Thermal Engineering,2017,112(4):1523-1532.
[11] Omran M,Fabritius T,Mattila,R. Thermally assisted liberation of high phosphorus oolitic iron ore:a comparison between microwave and conventional furnaces[J]. Powder Technology,2015,269(2):7-14.
[12] Whittles D N,Kingman S W,Reddish D J. Application of numerical modelling for prediction of the influence of power density on microwave-assisted breakage[J]. International Journal of Mineral Processing,2003,68(1):71-91.
[13] Jones D A,Kingman S W,Whittles D N,et al. Understanding microwave assisted breakage[J]. Minerals Engineering,2005,18(7):659-669.
[14] Jones D A,Kingman S W,Whittles D N,et al. The influence of microwave energy delivery method on strength reduction in ore samples[J]. Chemical Engineering and Processing(Process Intensification),2007,46(4),291-299.
[15] Hartlieb P,Leindl M,Kuchar F,et al. Damage of basalt induced by microwave irradiation[J]. Minerals Engineering,2012,31(3):82-89.
[16] Wang Y,Djordjevic N. Thermal stress FEM analysis of rock with microwave energy[J]. International Journal of Mineral Processing,2014,130(28):74-81.
[17]戴俊,秦立科.微波照射下岩石损伤细观模拟分析[J].西安科技大学学报,2014,34(6):652-655.DAI Jun,QIN Li-ke. Meso-simulation of rock damage under microwave irradiation[J]. Journal of Xi’an University of Science and Technology,2014,34(6):652-655.
[18] Like Q,Jun D. Analysis on the growth of different shapes of mineral microcracks in microwave field[J].Frattura ed Integrita Strutturale,2016,10(37):342-351.
[19] Ali A Y,Bradshaw S M. Quantifying damage around grain boundaries in microwave treated ores[J]. Chemical Engineering and Processing(Process Intensification),2009,48(11):1566-1573.
[20] Ali A Y,Bradshaw S M. Bonded-particle modelling of microwave-induced damage in ore particles[J]. Minerals Engineering,2010,23(10):780-790.
[21] Ali A Y,Bradshaw S M. Confined particle bed breakage of microwave treated and untreated ores[J]. Minerals Engineering,2011,24(14):1625-1630.
[22] Chen T T,Dutrizac J E,Hague K E,et al. The relative transparency of minerals to microwave radiation[J]. Canadian Metallurgical Quarterly,1984,23(3):349-351.
[23] Touloukian Y S,Judd W R. Physical properties of rocks and minerals[M]. New York:McGraw-Hill Book Company,1981.
[24] Bass J D. Elasticity of uvarovite and andradite garnets[J]. Journal of Geophysical Research Solid Earth,1986,91(B7):7505-7516.
[25] Clark S P. Handbook of physical constants[M]. New York:Geological Society of America,1966.
[26] QIN Li-ke,DAI Jun. Thermal stress distribution and evolution of concrete particles under microwave irradiation[J]. Journal of Engineering Science and Technology Review,2016,9(3):148-154.
[27] QIN Li-ke,DAI Jun,TENG Peng-fei. Study on the effect of microwave irradiation on rock strength[J]. Journal of Engineering Science and Technology Review,2015,8(4):91-96.
[28] QIN Li-ke,DAI Jun,ZHEN Jun-tian. Evolution of temperature and stress in rock under microwave irradiation[J]. Electronic Journal of Geotechnical Engineering,2015,20(28):13507-13516.
[29] QIN Li-ke,DAI Jun. Meso-mechanics simulation analysis of microwave-assisted mineral liberation[J]. Frattura de Integrita Strutturale,2015,9(34):543-553.