The Research Of Influence On The Flow And Heat Transfer By Vortex Generator

As an effective method of passive heat transfer enhancement, vortex generator is beingwidely used in various areas of heat transfer enhancement. Vortex generator is used todestruct the boundary layer of flow, which is an effective way to strengthen air side heattransfer. The method enhanced heat transfer technologies not only improve the efficiency ofheat transfer equipment, but require no additional power consumption, in accordance withtheir requirement of energy saving technology. Therefore, it is widely used in various fields.Vortex generators can be divided into transverse and longitudinal vortex generators.Inthis article, a cylinder and rectangular wing vortex is taken a example of transverse andlongitudinal vortex generators and researched in heat transfer and flow resistance, The flowand heat transfer characteristics of rectangle channel with rectangular wing and cylindervortex generators are obtained using large eddy simulation and by the application of thehydromechanics software Fluent. The instantaneous properties of velocity, temperature andvorticity in channel are gained. Large Eddy Simulation method was validated that it can getmore subtle turbulence structure and flow images in the complex flows. In addition, thisarticle also analysis the reason of transverse vortex generators and longitudinal vortexgenerators effect on heat transfer enhancement. Using dimensionless parameter thesecondary flow intensity to describe the secondary flow. Secondary flow intensity changeswith Reynolds number and secondary flow intensity changes with the Nusselt number areAnalysised. Eventually, Secondary flow intensity changes with the Nusselt number iscomputed by curves fitting.Secondly,the flow and heat transfer characteristics of rectangle channel with a, b, cwing and cylinder vortex generators are obtained using large eddy simulation (LES). Theinstantaneous properties of velocity, temperature and vorticity in channel are also gained. Inaddition heat transfer and flow resistance changes are analysised of the three differentsituations.It is indicated that b wing can reduce flow resistance than a wing,but it alsodecrease heat transfer.For a and c wings, c wing can reduce flow resistance than a wing,but it also reduces more heat transfer than a wing.Finally, the strcture of flow can be controlled by the size and geometric shape of vortexgenerators, Furtherly, it influences the properties of heat transfer and flow resistance. It canbe a theoretical guidance of seeking appropriate vortex generators for achieving heattransfer enhancement and flow resistance reduction.