We numerically investigate heat transfer enhancement by helically corrugated tubes (HCTs) in the intermediate heat exchanger (IHX) of a very-high-temperature gas-cooled reactor (VHTR). A comparison with heat transfer in a smooth tube shows that HCTs have better heat transfer over the full IHX temperature range. The helical corrugations strengthen the intensity of the turbulence and create rotational flow, which better mixes the fluid and improves the synergy between the velocity field and the temperature gradient field. The effects of tube structural parameters and fluid physical properties on the Nusselt number (Nu), friction factor, and performance evaluation criterion (PEC) were also analyzed. The corrugations have optimal heights for the maximum Nu and PEC. Nu decreases as the corrugation pitch increases, whereas the PEC shows the opposite trend. The best heat transfer enhancement is 1.69 for e/d = 0.03 and p/d = 0.4, and the best overall performance is 1.13 for e/d = 0.01 and p/d = 0.8, both of which are in the high-temperature region.

我们从数值上研究了高温气体冷却反应堆（VHTR）的中间热交换器（IHX）中螺旋波纹管（HCT）的传热增强。与光滑管中的传热进行比较表明，HCT在整个IHX温度范围内具有更好的传热。螺旋波纹增强了湍流的强度并产生了旋转流，从而更好地混合了流体并提高了速度场与温度梯度场之间的协同作用。还分析了管结构参数和流体物理性质对努塞尔数（Nu），摩擦系数和性能评估标准（PEC）的影响。波纹具有最大Nu和PEC的最佳高度。Nu随着波纹间距的增加而减小，而PEC则呈现相反的趋势。最佳的传热增强为1.69e / d  = 0.03和p / d  = 0.4，对于e / d  = 0.01和p / d  = 0.8而言，两者的最佳总体性能为1.13 ，两者均处于高温区域。