This work aims to study the thermal-hydrodynamic performance of innovative multi tubes in tube helically coiled (MTTHC) heat exchanger used in the heat pump system. The 3D finite volume method and realizable k-ε turbulence model is considered to investigate the mechanism of flow and heat transfer in this MTTHC heat exchanger with the different coiled diameter and coiled pitch. Predicted values of pressure drop and outlet temperature are compared with our previous experimental results. The comparison shows the numerical method can be well to use for evaluating the performance of this novel MTTHC. The distributions of velocity, temperature and pressure along the flow direction for the certain cross-sections are presented. The effects of structural parameters of MTTHC and flow rates of inner and outer tube on the overall heat transfer coefficient, effectiveness and NTU, pumping power and pressure drop, thermal and hydrodynamic performance index (ξ) and inner and outer tube Nusselt number are investigated. It is found that decreasing the coiled diameter or increasing the coiled pitch can improve thermal performance. In addition, increasing the flow rate leads to an increase in pressure drop and pumping power. However, ξ enhances with increasing m_w, and it worsens with increasing m_ref.

这项工作旨在研究热泵系统中使用的管螺旋式（MTTHC）换热器中的新型多管的热流体力学性能。3D有限体积法和可实现的k - ε考虑湍流模型，研究了不同盘绕直径和螺距的MTTHC换热器的流动和传热机理。将压降和出口温度的预测值与我们之前的实验结果进行比较。比较表明，数值方法可以很好地用于评估这种新型MTTHC的性能。给出了特定横截面沿流动方向的速度，温度和压力分布。MTTHC的结构参数以及内外管的流量对整体传热系数，效率和NTU，泵送功率和压降，热力和水动力性能指标（ξ）和内，外管Nusselt数进行了研究。发现减小线圈直径或增大线圈节距可以改善热性能。另外，增加流速导致压降和泵送功率的增加。但是，ξ随着m _w的增加而增强，而随着m _ref的增加而恶化。