Abstract: Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers, the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as well as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20° (20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure drop Δp_o, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient h_o and shell-side average comprehensive index h_o/Δp_o.

Key words: Helix baffled heat exchanger, Trisection baffle, Quadrant baffle, Continuous baffle, Circumferential overlap baffle, Secondary flow, Heat transfer, Numerical simulation

摘要： Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers, the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as well as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20° (20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure drop Δp_o, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient h_o and shell-side average comprehensive index h_o/Δp_o.

关键词: Helix baffled heat exchanger, Trisection baffle, Quadrant baffle, Continuous baffle, Circumferential overlap baffle, Secondary flow, Heat transfer, Numerical simulation