Numerical and experimental investigations of shape and location of vortex generators on fluid flow and heat transfer in a constant heat-fluxed rectangular duct

Abstract

A numerical and experimental study was conducted for heat transfer enhancement and fluid flow in a constant heat-fluxed rectangular wooden duct fitted with two shapes of vortex generators (circular and square). These vortex generators are of the same area and placed at two different locations ([Formula: see text] and [Formula: see text]) ahead of the heater set and for Reynolds number from 32,000 to 83,000. The numerical and experimental results show an enhancement of heat transfer with the presence of vortex generators. This enhancement depends on the shape and location. Also, the numerical results show saving of 27% of the heater power with the presence of vortex generator. The experimental results of temperature distribution, Nusselt number distribution, effectiveness distribution, and pressure drop values of flow over heaters with vortex generators were reported and compared with the flow over heaters without vortex generators. The results show that heat transfer was enhanced by 2.186%−3.75% using circular type, and it enhanced by 1.3%−1.94% using square type. Also, pressure drop at the outlet of the duct increases by 166.7%−400% when using circular vortex generators and increases by 133.3%−300% when using square vortex generators. These values were obtained for the velocity ranging between 4 and 10 m/s and when vortex generators were placed at location [Formula: see text]. Finally, correlation equations for Nusselt number were obtained at location [Formula: see text] ahead of the heater set.