This paper numerically investigates the effect of using some turbulators in a geothermal heat exchanger with the optimal arrangement. The geothermal heat exchanger includes a constant-temperature tube through which the nanofluid flow with Cu nanoparticles passes. In the geothermal heat exchanger, five conical turbulators are used on which there are some holes. By changing the radius of holes on turbulators, turbulator spacing, and length of each turbulator, the outlet nanofluid temperature, the nanofluid temperature in the tube, heat transfer coefficient, mean transverse kinetic energy, velocity contours, and nanofluid temperature in the geothermal heat exchanger are studied. Simulations are conducted using the finite element method, and the nanofluid flow is considered two-phase. Also, artificial intelligence is used to conduct a sensitivity analysis and optimization of results. Results of this study indicate that decreasing the turbulator spacing and decreasing the radius of turbulator holes, and arranging turbulators at moderate distances from each other increase the heat transfer coefficient by up to 27.9%. Increasing the turbulator spacing and diameter of holes leads to mean transverse kinetic energy reduction. The highest and lowest values of maximum nanofluid temperature in the tube are 309.77 K and 303.34 K. The outlet nanofluid temperature varies from 302.42 K to 306.57 K, and the most significant effect on the outlet nanofluid temperature is related to changing the radius of turbulator holes.

中文翻译：

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湍流器孔径对纳米流体地热换热器传热优化的影响

本文数值研究了在地热热交换器中使用一些湍流器并进行最佳布置的效果。地热热交换器包括恒温管，含有铜纳米颗粒的纳米流体流穿过该恒温管。在地热换热器中，使用五个锥形湍流器，其上有一些孔。通过改变湍流器上的孔半径、湍流器间距和每个湍流器的长度，可以得到地热换热器中出口纳米流体温度、管内纳米流体温度、传热系数、平均横向动能、速度轮廓和纳米流体温度被研究。使用有限元方法进行模拟，纳米流体流动被认为是两相的。此外，人工智能还用于进行敏感性分析和结果优化。这项研究的结果表明，减小湍流器间距和减小湍流器孔的半径，以及将湍流器彼此之间的距离布置得适中，可使传热系数最多增加 27.9%。增加湍流器间距和孔直径会导致平均横向动能降低。管内纳米流体最高温度最高和最低分别为309.77 K和303.34 K。出口纳米流体温度变化范围为302.42 K到306.57 K，对出口纳米流体温度影响最显着的因素与改变湍流器孔半径有关。