![]() Joardar A, Jacobi AM (2005) Impact of leading edge delta-wing vortex generators on the thermal performance of a flat tube, louvered-fin compact heat exchanger. He YL, Han H, Tao WQ, Zhang YW (2012) Numerical study of heat transfer enhancement by punched winglet-type vortex generator arrays in fin-and-tube heat exchangers. Myrum TA, Qiu S, Acharya S (1993) Heat transfer enhancement in a ribbed duct using vortex generators. Wani SA, Patil SR, Shrotri AP (2015) A review on effect of vortex generators on flow characteristics and heat transfer in heat exchangers. Johnson TR, Joubert PN (1969) The influence of vortex generators on drag and heat transfer from a circular cylinder normal to an air stream. Zhang L, Guo HM, Wu JH, Du WJ (2012) Compound heat transfer enhancement for shell side of double-pipe heat exchanger by helical fins and vortex generators. CIESC J (Off J Chem Ind Eng Soc China) 61(3):587–593 ![]() Zhang L, Tian MM, Wu JH (2010) Heat transfer enhancement for shell side of double-pipe heat exchanger with pin fins and helical fins. Zhang L, Tian MM, Wu JH (2011) Heat transfer performance of the shell side of double-pipe heat exchanger enhanced with helical fins. Quantity of the winglet pairs within one pitch NuĬoordination in the direction of the tube axis βĭimensionless torsion of the helical channel ηĭegree of one acute angle of the triangle winglet κĭimensionless curvature of the helical channel λ Total length of the centerline of the helical channel l Hydraulic diameter of the flow channel Dn Middle diameter of the helical channel D h Specific heat of air at constant pressure D Length of the downstream edge of the vortex generators c p Length of the upstream edge of the vortex generators b The enhancement effect of isosceles right triangle is better than that of right triangle in which one acute angle is 30°.Ĭross-sectional area of the flow channel a Installation of three pairs of VG within one pitch is an optimal design for the shell side used in the present experiments. Under the three constraints, i.e., identical mass flow rate, identical pressure drop and identical pumping power, the largest VG size can achieve the best enhancement effect. Under identical pressure drop condition, the angle of attack of 30° is the best choice compared with 45° and 60°. The vortices and the unsteadiness of the flow introduced by the VG make a great contribution to the increase. The results show that, the heat exchange effectiveness of the shell side with VG is 16.6 % higher than that without VG. Air was used as working fluid within the range of Re from 680 to 16,000. ![]() The effects of the arrangement of the triangle-winglet-pair VG, such as the geometry, the angle of attack and the quantity on heat transfer performance and pressure drop characteristics have been investigated experimentally to find out the optimal design of the VG. To improve heat transfer performance of the shell side of a double-pipe heat exchanger enhanced by helical fins, triangle-winglet-pair vortex generators (VG) were installed along the centerline of the helical channel with rectangular cross section.
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