The uneven (flow) resistance of branched pipes commonly causes local overheating and freezing in solar collector fields. In this paper, the resistance characteristics of the direct return flat plate solar collector field are studied using a numerical model. The accuracy of the model is verified with experimental data, and the maximum relative error is below 10%. A new evaluation index, the ratio of resistance imbalance rate to efficiency (R_RIRE), is introduced. In this way, it is possible to comprehensively evaluate the effect of different factors (configuration, flow rate per unit heat collection area, inlet temperature, working medium) on both the resistance characteristics and efficiency of the solar collector field. The results show that, when the number of rows (N_row) exceeds the number of collectors in each row (N_col), the inlet temperature is below 40 °C. In addition, the flow rate per unit heat collection area is below 0.06 m³/(h m²). Hence, the R_RIRE is smaller and the system has better resistance efficiency. Considering the viscosity change due to the temperature change in the fluid of the solar collector field, a new temperature difference correction method is proposed. This makes it possible to calculate the frictional drag for a fluid in the collector field, which allows a more realistic calculation of flow resistance. This study lays the foundation for improved layout design and parameter optimization in solar collector fields.

支管的不均匀（流动）阻力通常会导致太阳能集热器区域中的局部过热和冻结。本文利用数值模型研究了直接返回平板太阳能集热器场的电阻特性。实验数据验证了模型的准确性，最大相对误差在10％以下。引入了一种新的评估指标，即电阻不平衡率与效率之比（R _RIRE）。这样，可以综合评估不同因素（配置，单位集热面积的流速，入口温度，工作介质）对太阳能集热器场的电阻特性和效率的影响。结果表明，当行数（N_行）超过每行收集器的数量（N _col），入口温度低于40°C。另外，每单位集热面积的流量低于0.06m ³ /（hm ²）。因此，R _RIRE较小，系统具有更好的电阻效率。考虑到太阳能集热器场内流体温度变化引起的粘度变化，提出了一种新的温差修正方法。这样就可以计算出收集器场中流体的摩擦阻力，从而可以更实际地计算流动阻力。该研究为改进太阳能集热器领域的布局设计和参数优化奠定了基础。