The effects of combined using of water-graphene nanoplatelet nanofluid and three different conical wire coils (converging, converging-diverging and diverging) on thermohydraulic performance of a heat exchanger tube are experimentally studied. Three different weight fractions 0.5, 0.75 and 1% of Graphene-Water nanofluids are used and converging, converging-diverging, diverging conical wire coils with two different pitch ratios 2 and 3 are selected for the experiments. The experiments are conducted under constant heat flux and Reynolds number ranging from 4000 to 27,000. The results indicated that use of conical wire coils cause to increase both the heat transfer rate and fluid friction as expected, in addition, adding the graphene nanoplatelet in pure water leads to strongly increase in heat transfer rate meanwhile cause to slightly increase in friction factor. Experimental results revealed that combination of diverging conical wire coil insert with weight fraction of 1% Graphene-Water nanofluid provides higher heat transfer performance than the other cases. The highest Performance Evaluation Criteria of 1.73 is observed while the diverging conical wire coil, which has the pitch ratio of 2, at Reynolds number of 6128 for weight fraction of 1% Graphene-Water nanofluid.

实验研究了水石墨烯纳米片纳米流体与三种不同的锥形线盘管（会聚，会聚-发散和发散）组合使用对换热管热工水力性能的影响。使用三种不同的重量分数分别为0.5、0.75和1％的石墨烯-水纳米流体，并选择具有两种不同螺距比2和3的会聚，会聚，发散，发散的圆锥形线圈进行试验。实验是在恒定热通量和雷诺数范围为4000至27,000的条件下进行的。结果表明，使用圆锥形线圈可以使传热速率和流体摩擦均达到预期的水平，此外，在纯水中添加石墨烯纳米薄片会导致传热速率大大增加，同时导致摩擦系数略有增加。实验结果表明，发散的圆锥形线圈插入物与重量百分比为1％的石墨烯-水纳米流体的组合提供了比其他情况更高的传热性能。当1％石墨烯-水纳米流体的重量分数为6128的雷诺数时，观察到最高的性能评估标准1.73，而螺距为2的锥形盘绕线圈。