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Applications of Variational Fracture: Enhanced Geothermal Systems

变分断裂的应用：增强型地热系统

基本信息

批准号：
0908267
负责人：
Blaise Bourdin
金额：
$ 31.41万
依托单位：
Louisiana State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-15 至 2013-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908267&HistoricalAwards=false
关键词：
Applications Variational Fracture Enhanced Geothermal

项目摘要

BourdinDMS-0908267 This award is funded under the American Recovery andReinvestment Act of 2009 (Public Law 111-5). Enhanced geothermal systems represent a virtually untapped,clean, renewable, economically viable, and widely availablesource of energy. They rely on harvesting heat by circulatingwater through artificially stimulated fracture systems in deephot dry rocks. This project provides a predictive understandingof the mechanisms commonly used to generate these systems:pressure- and temperature-driven fracture. The modeling andanalysis are based on a variational fracture formulation, whichhas been developed over the last ten years or so and has strongmathematical and mechanical foundations. The investigatorextends this formulation to dynamic fractures and improves itsimplementation on parallel supercomputers. He extends its scopeby studying and implementing two approaches to the penalizationof material interpenetration along crack lips. He developsvariational models for the pressure- and temperature-drivenfracture problems, approximates them using the idea ofGamma-convergence, implements the regularized models on parallelsupercomputers, and conducts large scale realistic validationexperiments that are compared with existing engineeringliterature. This project is a first step in a nascentmulti-disciplinary initiative fostered through the Center forComputation and Technology at LSU, involving mathematicians,computational scientists, and engineers. It supports theparticipation of two undergraduates and one graduate student peryear. As the Nation strives to reduce its carbon footprint,protect its economy from fluctuating oil prices, and increase itsenergy independence, Enhanced Geothermal Systems (EGS) representa virtually untapped, clean, renewable, economically viable andwidely available source of energy. They rely on harvesting heatby circulating water through artificially stimulated, highlyconnected fracture systems in deep hot dry rocks. A recentMIT-led interdisciplinary assessment panel commissioned by theDepartment of Energy estimates that even without major technicalbreakthroughs EGS could cover 20% of the estimated US electricityneeds by 2050, in an economically viable way and with onlymarginal carbon emission and land use. A major technical issueidentified in this report is the creation of sufficientlyconnected fracture systems. The investigator develops apredictive understanding of two mechanisms commonly used togenerate these systems: pressure- and temperature-drivenfracture, based on a mechanically faithful and mathematicallysound variational formulation of fracture developed over the lastdecade. This model is extended to account for the specifics ofEGS, then implemented on parallel supercomputers. Large scalenumerical simulations are performed using the cyberinfrastructureprovided by the TeraGrid, to allow EGS designers to devisestimulation patterns maximizing the efficiency and sustainabilityof new systems. This project is a first step in a nascentmulti-disciplinary initiative fostered through the Center forComputation and Technology at LSU, involving mathematicians,computational scientists, and engineers. It supports each yearthe participation of two undergraduates and one graduate student.

BourdinDMS-0908267 该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。增强型地热系统代表了一种几乎未开发、清洁、可再生、经济可行且广泛可用的能源。他们依靠在深层干燥岩石中人工模拟裂缝系统循环水来获取热量。该项目提供了一个预测性的理解机制，通常用于产生这些系统：压力和温度驱动的裂缝。建模和分析是基于变分断裂公式，这是近十年来发展起来的，具有很强的数学和力学基础。该算法将该公式扩展到动态裂缝，并改进了其在并行超级计算机上的实现。他通过研究和实施两种方法来扩展其范围，以惩罚沿着裂纹唇的材料渗透。他开发了压力和温度驱动断裂问题的变分模型，使用Gamma收敛的思想对其进行近似，在并行超级计算机上实现正则化模型，并进行了与现有工程文献相比的大规模现实验证实验。该项目是通过路易斯安那州立大学计算与技术中心培养的新生多学科倡议的第一步，涉及数学家，计算科学家和工程师。它每年支持两名本科生和一名研究生的参与。随着国家努力减少碳足迹，保护经济免受油价波动的影响，并提高能源独立性，增强型地热系统（EGS）代表了几乎未开发的，清洁的，可再生的，经济上可行的和广泛可用的能源。他们依靠通过人工刺激的，高度连接的深层干热岩石中的断裂系统循环水来收集热量。一个最近由麻省理工学院领导的跨学科评估小组委托能源部估计，即使没有重大的技术突破，EGS也可以以经济上可行的方式满足2050年美国估计电力需求的20%，并且只有少量的碳排放和土地使用。本报告中确定的一个主要技术问题是建立紧密相连的断裂系统。研究人员开发了一个预测性的理解，两种机制通常用于产生这些系统：压力和温度驱动的fracture，基于一个机械上忠实的和prosticallysound变分公式的断裂在过去的十年。该模型扩展到帐户的具体ofEGS，然后在并行超级计算机上实现。使用TeraGrid提供的网络基础设施进行大规模的计算机模拟，以使EGS设计人员能够最大限度地提高新系统的效率和可持续性。该项目是通过路易斯安那州立大学计算与技术中心培养的新生多学科倡议的第一步，涉及数学家，计算科学家和工程师。它每年支持两名本科生和一名研究生的参与。