为了得到绕管式换热器壳侧冷凝传热下的流动及传热压降相关规律，通过数值模拟的方法建立了三维、瞬态的绕管式换热器壳侧冷凝传热计算模型。基于该模型对壳侧流体流场特性进行详细分析，对不同质量流量G和热流密度q_wall下的组合工况进行了模拟计算，来研究其对壳侧冷凝传热和压降特性的影响。结果表明：热流密度不变下：随质量流量的增加，表面传热系数h_s逐渐下降，但下降速度逐渐减小；努塞尔数Nu随质量流量增加而增加，对于低热流密度（≤ - 50 kW/m²），其增加速度先减小再增大，而在高热流密度（> - 50 kW/m²）下，增加速度则先增大后减小；质量流量不变：热流密度增加，h_s上升，Nu增加，且Nu增加幅度随质量流量增加而加大；随干度增加，dP/dl先增大后减小，转折点约在干度为0.8附近，表明其与干度和流型密切相关。

In order to elucidate the flow and pressure drop characteristics associated with condensation heat transfer on the shell side of a helical tube heat exchanger, a three-dimensional transient numerical simulation model was developed. Utilizing this model, a detailed analysis of the shell-side fluid flow characteristics was performed. Numerical simulations were conducted under various combinations of mass flux (G) and heat flux (q_wall) to investigate their influence on shell-side condensation heat transfer and pressure drop behavior. The results show as follows. For constant heat flux: as the mass flow rate increases, the surface heat transfer coefficient h_s gradually decreases, with a progressively slower rate of decline. The Nusselt number Nu increases with mass flow rate. For low heat flux (≤ - 50 kW/m²), the growth rate of Nu initially decreases and then increases, whereas for high heat flux (> - 50 kW/m²), the growth rate initially rises before declining. For constant mass flow rate:increasing the heat flux results in an increase in h_s, while Nu also rises, with a greater growth rate as mass flow rate increases. The pressure gradient (dP/dl) initially increases and then decreases with rising vapor quality, with a critical turning point occurring at a vapor quality of approximately 0.8. This observation highlights the strong interplay between the pressure gradient, vapor quality, and flow regime.