Deng Bin,Wu Yang,Tao Wenquan
(State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract:Three-dimensional numerical simulation was performed for the fluid flow and heat transfer in the shell side of shell-and-tube heat exchangers with helical baffles on the basis of porous medium and distributed resistance assumptions.The improved k-¦Å turbulence model in conjunction with wall function and the stepª²wise approximation technique were adopted.It is found that for the same inner diameter and shell-side flow rate the pressure drop in the shell with helical baffles is appreciably lower than those of shell with vertical baffles,and with the increase of the helical angle, the pressure drop tends downwards. Compared with the test data obtained for small flow rate, the numerical results coincide satisfactorily with an average deviation below 14£¥ and the maximum deviation of 18£¥.
Keywords:shell-and-tube heat exchangers with helical baffles;porous medium model;numerical simulation