In this study, a fast numerical method for solving the forced convection conjugate heat transfer problem was developed. The method first proposes a new dimensionless number (Fs) that represents the degree of influence of convection on the temperature field in the flow field. It delineates the stage of development of the flow field by monitoring the change in Fs to determine the moment when the flow field suspends updating and improve the computational efficiency of the transient temperature field. The accuracy of the algorithm is verified by taking the fluid–solid conjugate heat transfer under forced convection conditions as an example, which can accurately capture the changes of the flow field for a given monitoring step number of 100, and classify the flow field into E3, E4 and E5 development stages according to the judgment criteria. The results show that the higher development stages correspond to smaller levels of root mean square error (RMSE) of monitoring point temperatures within 3600 s of physical simulation time, and stages E3, E4, and E5 can reach the levels of E-2, E-3, and E-4, which are 3.4, 3.3, and 3.1 times faster than the traditional coupled calculations, respectively. The algorithm is still applicable at variable time steps, but it will require a higher number of determinations compared to a fixed step. The initial error of the quasi-steady algorithm can be reduced from the E-1 level to E-4 by choosing a higher stage of development. Finally the algorithm is tested under a variety of conditions by varying the inlet temperature and flow rate and is found to be robust to both device warming and cooling.

中文翻译：

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基于流场发展阶段划分的快速流固耦合传热算法

在这项研究中，开发了一种解决强制对流共轭传热问题的快速数值方法。该方法首先提出了一个新的无量纲数（Fs）来表示流场中对流对温度场的影响程度。它通过监测Fs的变化来勾画流场的发展阶段，以确定流场暂停更新的时刻，提高瞬态温度场的计算效率。以强制对流条件下的流固共轭传热为例验证了算法的准确性，能够准确捕捉给定监测步数100的流场变化，并将流场分类为E3级根据判断标准，分为E4和E5发展阶段。结果表明，发展阶段越高，物理模拟时间3600 s内监测点温度均方根误差（RMSE）水平越小，E3、E4、E5阶段可达到E-2、E水平-3和E-4，分别比传统耦合计算快3.4、3.3和3.1倍。该算法仍然适用于可变时间步长，但与固定步长相比，它需要更多的确定次数。通过选择更高的发展阶段，准稳态算法的初始误差可以从E-1级降低到E-4级。最后，通过改变入口温度和流速，在各种条件下对该算法进行了测试，结果发现该算法对于设备加热和冷却都很稳健。