{"title":"深部矿井回填热交换器的参数优化","authors":"Ya Yin , Lan Qiao , Qingwen Li , Lu Chen","doi":"10.1016/j.geothermics.2024.103091","DOIUrl":null,"url":null,"abstract":"<div><p>Based on the current status of laying buried pipes in the backfill to extract geothermal at home and abroad, a three-dimensional non-steady-state Mineral-geothermal co-mining model was established using COMSOL software. Firstly, under the same geometric and physical conditions, the performance of S-S, T-S and <span>l</span>-S Backfill Heat Exchanger (BFHE) were compared and analyzed. The results showed that the comprehensive evaluation index of the S-S BFHE was better than that of T-S and <span>l</span>-S BFHE. Secondly, the influence of pipe diameter <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, inlet temperature <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> and flow velocity <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> of circulating medium, thermal conductivity <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span>and specific heat capacity <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span>of the backfill on the coupled heat pump characteristics were studied. It was found that increasing the <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span> can increase the heat transfer efficiency, but the improvement in heat transfer performance is not significant when it reaches a certain size. Low <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> can achieve higher heat exchange efficiency. Increasing the <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> can effectively improve heat transfer efficiency, but it is also limited. Considering the heat transfer efficiency, <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span>, and <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> are recommended to be around 30–35 mm, 10–12℃, and 0.4–0.6 m/s respectively. The high <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span> and <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span> can effectively increase the heat transfer performance of BFHE. Based on this, the relative sensitivity parameter was introduced to discuss the sensitivity of different influencing factors to the total heat transfer <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span>. The results showed that only the <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> had a negative impact on the <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span>. The influence of <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span>, <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, and <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> on <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span> gradually weakened with heat transfer time, while the influence of <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span> gradually increased. Over extended periods of operation, the thermal parameters of the backfill exert the greatest influence on the heat transfer performance of BFHEs, with thermal conductivity having the most significant effect, followed by specific heat capacity.</p></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Optimization of parameters for backfill heat exchanger in deep mines\",\"authors\":\"Ya Yin , Lan Qiao , Qingwen Li , Lu Chen\",\"doi\":\"10.1016/j.geothermics.2024.103091\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Based on the current status of laying buried pipes in the backfill to extract geothermal at home and abroad, a three-dimensional non-steady-state Mineral-geothermal co-mining model was established using COMSOL software. Firstly, under the same geometric and physical conditions, the performance of S-S, T-S and <span>l</span>-S Backfill Heat Exchanger (BFHE) were compared and analyzed. The results showed that the comprehensive evaluation index of the S-S BFHE was better than that of T-S and <span>l</span>-S BFHE. Secondly, the influence of pipe diameter <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, inlet temperature <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> and flow velocity <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> of circulating medium, thermal conductivity <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span>and specific heat capacity <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span>of the backfill on the coupled heat pump characteristics were studied. It was found that increasing the <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span> can increase the heat transfer efficiency, but the improvement in heat transfer performance is not significant when it reaches a certain size. Low <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> can achieve higher heat exchange efficiency. Increasing the <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> can effectively improve heat transfer efficiency, but it is also limited. Considering the heat transfer efficiency, <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span>, and <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> are recommended to be around 30–35 mm, 10–12℃, and 0.4–0.6 m/s respectively. The high <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span> and <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span> can effectively increase the heat transfer performance of BFHE. Based on this, the relative sensitivity parameter was introduced to discuss the sensitivity of different influencing factors to the total heat transfer <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span>. The results showed that only the <span><math><msub><mi>T</mi><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span> had a negative impact on the <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span>. The influence of <span><math><msub><mi>λ</mi><mi>b</mi></msub></math></span>, <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, and <span><math><msub><mi>u</mi><mi>f</mi></msub></math></span> on <span><math><msub><mi>Q</mi><mrow><mi>B</mi><mi>F</mi><mi>H</mi><mi>E</mi></mrow></msub></math></span> gradually weakened with heat transfer time, while the influence of <span><math><msub><mi>C</mi><msub><mi>P</mi><mi>b</mi></msub></msub></math></span> gradually increased. Over extended periods of operation, the thermal parameters of the backfill exert the greatest influence on the heat transfer performance of BFHEs, with thermal conductivity having the most significant effect, followed by specific heat capacity.</p></div>\",\"PeriodicalId\":55095,\"journal\":{\"name\":\"Geothermics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2024-07-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geothermics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0375650524001792\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geothermics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0375650524001792","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
Optimization of parameters for backfill heat exchanger in deep mines
Based on the current status of laying buried pipes in the backfill to extract geothermal at home and abroad, a three-dimensional non-steady-state Mineral-geothermal co-mining model was established using COMSOL software. Firstly, under the same geometric and physical conditions, the performance of S-S, T-S and l-S Backfill Heat Exchanger (BFHE) were compared and analyzed. The results showed that the comprehensive evaluation index of the S-S BFHE was better than that of T-S and l-S BFHE. Secondly, the influence of pipe diameter , inlet temperature and flow velocity of circulating medium, thermal conductivity and specific heat capacity of the backfill on the coupled heat pump characteristics were studied. It was found that increasing the can increase the heat transfer efficiency, but the improvement in heat transfer performance is not significant when it reaches a certain size. Low can achieve higher heat exchange efficiency. Increasing the can effectively improve heat transfer efficiency, but it is also limited. Considering the heat transfer efficiency, , , and are recommended to be around 30–35 mm, 10–12℃, and 0.4–0.6 m/s respectively. The high and can effectively increase the heat transfer performance of BFHE. Based on this, the relative sensitivity parameter was introduced to discuss the sensitivity of different influencing factors to the total heat transfer . The results showed that only the had a negative impact on the . The influence of , , and on gradually weakened with heat transfer time, while the influence of gradually increased. Over extended periods of operation, the thermal parameters of the backfill exert the greatest influence on the heat transfer performance of BFHEs, with thermal conductivity having the most significant effect, followed by specific heat capacity.
期刊介绍:
Geothermics is an international journal devoted to the research and development of geothermal energy. The International Board of Editors of Geothermics, which comprises specialists in the various aspects of geothermal resources, exploration and development, guarantees the balanced, comprehensive view of scientific and technological developments in this promising energy field.
It promulgates the state of the art and science of geothermal energy, its exploration and exploitation through a regular exchange of information from all parts of the world. The journal publishes articles dealing with the theory, exploration techniques and all aspects of the utilization of geothermal resources. Geothermics serves as the scientific house, or exchange medium, through which the growing community of geothermal specialists can provide and receive information.