为充分考虑地热梯度、提高模型计算效率,采用分段方法建立闭式U型井换热器的传热解析模型,并编写程序实现模型的耦合计算。利用系统实际运行数据对模型进行精度验证,并对入口温度和循环流量2个运行参数对地热井取热性能的影响进行分析。结果表明：经与以光纤传感器实测数据在沿程方向上的对比,该模型的平均相对误差为7.3%,模型精度满足工程使用要求。在保证基础负荷需求的前提下,地热井入口温度保持在5~16 ℃之间,循环流量在80 m3/h以上时,可保证地热井处于高效运行区间。在该工况区间内,降低入口温度比提高循环流量能获得更好的热经济性,合理的入口温度和循环流量的匹配调节能使地热井的供热能力提高10%。
Abstract
In order to fully consider the geothermal gradient and improve the calculation efficiency of the model, the heat transfer analytical model of closed U-shaped well heat exchanger is established by piecewise method, and the coupled calculation of the model is realized by programming. The accuracy of the model was verified by using the actual operation data of the system. Based on the model, the influences of the two operating parameters, inlet temperature and circulating flow, on the heat recovery of geothermal wells are analyzed. The results show that, compared with the measured data of optical fiber sensor, the average relative error of the model is 7.3%, and the accuracy of the model can meet the engineering requirements. On the premise of ensuring the basic load requirements, the geothermal well inlet temperature is between 5 ℃ and 16 ℃, and the circulating flow rate is above 80 m3/h, which can ensure the geothermal well in the efficient operation interval. In this operating range, the better thermal economy can be obtained by lowering the inlet temperature than by increasing the circulating flow, and the reasonable matching regulation of inlet temperature and circulating flow can increase the heating capacity of geothermal wells by 10%.
关键词
地热井 /
传热分析 /
运行优化 /
入口温度 /
循环流量 /
换热器
Key words
geothermal well /
heat transfer analytical /
operation optimization /
inlet temperature /
circulating flow /
heat exchanger
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