Single helical tube has been widely investigated in both smooth wall and corrugated wall structures. However, for the first time, this paper proposes and works on a helical tube-in-tube heat exchanger in which both inner tube and outer tube are corrugated (see graphical abstract for possible interesting configurations). The idea of the fabrication process of such heat exchanger will be the first challenge; and that is why the first part of this research explains what steps are required to fabricate the mentioned heat exchanger with affordable and available industrial techniques. When both inner tube and outer tube are corrugated, the relative position of the corrugations on both tubes provides different configurations (see case “c” and “d” in the graphical abstract) with completely different behaviors. In the second step, the numerical simulation of the mentioned heat exchanger is validated with the experimental results. At the third part of the paper, a comprehensive simulation is performed to analyze the mentioned heat exchanger from thermal, frictional and exergetic viewpoints. The results show that the corrugating of the outer tube in addition to the inner tube significantly boosts the thermal capacity of the heat exchanger without any further weight, area or size of the heat exchanger (case “d” provides 125% higher Nu number compared to the case “a”). Besides, the mentioned relative position of the corrugations plays a significant role so that the obtained Nu number of case “d” is 35% higher than that of case “c” (the difference of these cases is only the relative position of the corrugations). The reason of all these phenomenon and other remarkable findings are reported in this paper.

单螺旋管已在光滑壁和波纹壁结构中得到广泛研究。然而，本文首次提出并研究了一种内管和外管都是波纹的螺旋管式管换热器（有关可能的有趣配置，请参见图形摘要）。这种热交换器的制造过程的想法将是第一个挑战；这就是为什么本研究的第一部分解释了使用负担得起且可用的工业技术制造上述热交换器需要哪些步骤。当内管和外管都有波纹时，两个管上波纹的相对位置提供不同的配置（参见图形摘要中的案例“c”和“d”），具有完全不同的行为。第二步，上述换热器的数值模拟得到了实验结果的验证。在论文的第三部分，进行了全面的模拟，从热、摩擦和热能的角度分析了上述换热器。结果表明，除了内管外，外管的波纹显着提高了换热器的热容量，而无需进一步增加换热器的重量、面积或尺寸（案例“d”提供了 125%Nu数与情况“a”相比）。此外，提到的波纹的相对位置起着重要作用，因此“d”案例获得的Nu数比“c”案例高35%（这些案例的差异仅在于波纹的相对位置） . 本文报道了所有这些现象的原因和其他显着的发现。