laminar heat transfer augmentation by low-pressure-drop motionless mixers: an experimental study

Heat transfer characteristics in a circular tube fitted with motionless mixer have been investigated experimentally air was used as working fluid and the experiments were conducted under uniform surface heat flux and in laminar flow regime over a range of reynolds number from 500 to 2000 two lpd and llpd static mixers were also used as vortex generators the results show that the increase in nusselt number is apparently due to the positive influence of the mixer blades, which magnify the viscosity ratio effect and pro uce vortex flow effects a relatively higher heat transfer rate was obtained by lpd mixer due to strong mixing effect that causes high temperature gradient in the radial direction and disrupting the growth of the boundary layer furthermore, the correlation presented for mean nusselt number shows a deviation within ±12 percent from experimental data