关键词: 三分螺旋折流板换热器, 流场, 二次流, 湍流动能, 换热系数

Abstract: Using the numerical simulation of end to end tube-and-shell heat exchangers with trisection helical baffles with 35°inclined angle, this research demonstrated the distribution of the flow field and streamline on the typical sections of fluid in the shell side channel, as well as the distribution of flow and heat transfer parameters of typical straight lines on the typical sections. The results showed that the approximate spiral channel composed by helical baffles impelled the Dean vortex secondary flow formed by the combined effect of centrifugal and centripetal force, and the Dean vortex secondary flow existed in each spiral cycle. the secondary flow enhanced the mixing of fluid in mainstream region and fluid near the wall, resulting a larger axial velocity of the centerline and the outer edge straight line on the typical sections. Other than the mainstream center region, the shell side fluid had uniform turbulent kinetic energy in the role of secondary flow. The heat transfer coefficient on the concentric cylindrical surface differed little in the secondary flow region，however, heat transfer can be enhanced due to the fact that the secondary flow was continuously entraining the fluid of the adjacent areas.

Key words: trisection helical baffled heat exchangers, flow field, secondary flow, turbulent kinetic energy, heat transfer coefficient