U型中深层地埋管换热器(U-bend Deep Borehole Heat Exchanger,UDBHE)可有效开采中深层地热能,具有较高的换热性能,因而备受关注。中深层岩土热物性一般随深度而变化,而目前缺乏分层岩土热物性对U型中深层地埋管换热器传热性能影响的深...U型中深层地埋管换热器(U-bend Deep Borehole Heat Exchanger,UDBHE)可有效开采中深层地热能,具有较高的换热性能,因而备受关注。中深层岩土热物性一般随深度而变化,而目前缺乏分层岩土热物性对U型中深层地埋管换热器传热性能影响的深入研究。文章基于已经建立的UDBHE半解析传热模型,研究了分层岩土热物性(热导率和体积比热容)对UDBHE传热性能的影响。研究结果表明:各层岩土热导率和体积比热容对UDBHE传热性能均有一定影响,并且其影响均随着岩土层深度的增大而增大;随着时间的增加,岩土热导率造成的影响逐渐增大,而岩土体积比热容造成的影响基本不变。保持各层岩土热导率的加权平均值不变,岩土热导率非均匀性对传热性能有较大影响,并且较大的岩土热导率非均匀性程度将促进UDBHE传热性能,反之则抑制。同理,岩土体积比热容非均匀性也有一定影响,但其影响随时间变化很小。研究结果对UDBHE性能预测及优化提供重要的参考价值。展开更多
The pre-crack blast technology has been used to control the induction caving area in the roof. The key is to form the pre-crack seam and predict the effect of the seam. The H-J-C blast model was built in the roof. Bas...The pre-crack blast technology has been used to control the induction caving area in the roof. The key is to form the pre-crack seam and predict the effect of the seam. The H-J-C blast model was built in the roof. Based on the theories of dynamic strength and failure criterion of dynamic rock, the rock dynamic damage and the evolution of pre-crack seam were simulated by the tensile damage and shear failure of the model. According to the actual situation of No. 92 ore body test stope at Tongkeng Mine, the formation process of the pre-crack blast seam was simulated by Ansys/Ls-dyna software, the pre-crack seam was inspected by a system of digital panoramic borehole camera. The pre-crack seam was inspected by the system of digital panoramic borehole in the roof. The results of the numerical simulation and inspection show that in the line of centers of pre-hole, the minimum of the tensile stress reaches 20 MPa, which is much larger than 13.7 MPa of the dynamic tensile strength of rock. The minimum particle vibration velocity reaches 50 cm/s, which is greater than 30-40 cm/s of the allowable vibration velocity. It is demonstrated that the rock is destroyed near the center line and the pre-crack is successfully formed by the large diameters and large distances pre-crack holes in the roof.展开更多
文摘U型中深层地埋管换热器(U-bend Deep Borehole Heat Exchanger,UDBHE)可有效开采中深层地热能,具有较高的换热性能,因而备受关注。中深层岩土热物性一般随深度而变化,而目前缺乏分层岩土热物性对U型中深层地埋管换热器传热性能影响的深入研究。文章基于已经建立的UDBHE半解析传热模型,研究了分层岩土热物性(热导率和体积比热容)对UDBHE传热性能的影响。研究结果表明:各层岩土热导率和体积比热容对UDBHE传热性能均有一定影响,并且其影响均随着岩土层深度的增大而增大;随着时间的增加,岩土热导率造成的影响逐渐增大,而岩土体积比热容造成的影响基本不变。保持各层岩土热导率的加权平均值不变,岩土热导率非均匀性对传热性能有较大影响,并且较大的岩土热导率非均匀性程度将促进UDBHE传热性能,反之则抑制。同理,岩土体积比热容非均匀性也有一定影响,但其影响随时间变化很小。研究结果对UDBHE性能预测及优化提供重要的参考价值。
基金Project(2006BAB02A02)supported by the National Key Technology R&D Program for the 11th Five-year Plan of ChinaProject(09JJ4025)supported by the National Natural Science Foundation of Hunan Province,ChinaProject(51074178)supported by the National Natural Science Foundation of China
文摘The pre-crack blast technology has been used to control the induction caving area in the roof. The key is to form the pre-crack seam and predict the effect of the seam. The H-J-C blast model was built in the roof. Based on the theories of dynamic strength and failure criterion of dynamic rock, the rock dynamic damage and the evolution of pre-crack seam were simulated by the tensile damage and shear failure of the model. According to the actual situation of No. 92 ore body test stope at Tongkeng Mine, the formation process of the pre-crack blast seam was simulated by Ansys/Ls-dyna software, the pre-crack seam was inspected by a system of digital panoramic borehole camera. The pre-crack seam was inspected by the system of digital panoramic borehole in the roof. The results of the numerical simulation and inspection show that in the line of centers of pre-hole, the minimum of the tensile stress reaches 20 MPa, which is much larger than 13.7 MPa of the dynamic tensile strength of rock. The minimum particle vibration velocity reaches 50 cm/s, which is greater than 30-40 cm/s of the allowable vibration velocity. It is demonstrated that the rock is destroyed near the center line and the pre-crack is successfully formed by the large diameters and large distances pre-crack holes in the roof.
