折流板结构对换热器壳程性能影响的定量研究

Quantitative research on effect of different baffle structures on performance of heat exchanger's shell side

针对弓形折流板、连续螺旋折流板换热器,采用CFD软件FLUENT,RNG k-ε模型,借助数值模拟的方法,定量地比较2种折流板结构下换热器的压降、传热系数、综合性能,并进一步分析了不同折流板结构下换热器壳程局部流场和温度场的分布特点。结果表明:同连续螺旋折流板换热器相比,弓形折流板换热器壳程速度场和温度场分布存在着明显的不连续性。弓形折流板相邻折流板间距同连续螺旋折流板螺距相同条件下,折流板螺距较小时,采用连续螺旋折流板能够明显提高换热器传热系数,但折流板结构改变对换热器综合性能的影响不大;增大折流板螺距,采用连续螺旋折流板能够明显提高换热器综合性能,但不同折流板结构下换热器传热系数变化不大。计算结果为折流板结构的选用提供了理论依据。

The pressure drop, heat transfer coefficient and comprehensive performance of segmental baffles and continuous helical baffles heat exchangers were quantitatively compared by numerical simulation, based on CFD analysis software Fluent and RNG k-s model. Local flow field and temperature field of heat exchangers with different baffle structures were further analyzed. The results show that the shell side velocity field and temperature field distribution of segmental baffles heat exchanger present obvious discontinuity. When the distance between two adjacent baffles of segmental baffles and pitch of continuous helical baffles are the same, and pitch of baffles is smaller, continuous helical baffles can significantly improve heat transfer coefficient, but the structure of baffle has little effect on comprehensive performance. Yet when the pitch of baffles increases to an extent, continuous helical baffles can obviously improve comprehensive performance, but the structure of baffle makes little difference on heat transfer coefficient. The results provide the theoretical basis for the selection of baffle structures.