Comparison of heat transfer performances of helix baffled heat exchangers with different baffle configurations

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 Δpo, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient ho and shell-side average comprehensive index ho/Δpo.

Graphical abstractNumerical simulations were performed on flow and heat transfer performances of six helical baffle heat exchangers exhibiting approximate spiral pitch but with different baffle shapes and assembly configurations, including trisection baffles, quadrant baffles and continuous helical baffles. The results show that the 20° incline angled circumferential overlap baffle scheme 20°TCO has the highest shell-side heat transfer coefficient and average comprehensive index ho/Δpo; while the axial middle overlap baffle scheme 36.2°TMO has the lowest ho and the second lowest ho/Δpo; and the continuous helical baffle scheme 18.4°CH has the second lowest ho and the third lowest ho/Δpo among the six schemes.Figure optionsDownload full-size imageDownload as PowerPoint slide