Abstract: The heat transfer enhancement and pressure drop characteristics of a pair of oblique-cut semi-elliptic cylinder shell vortex generators(aspect ratio h/b= 1/2) in a rectangular channel are experimentally investigated by changing the elevation angle , attack angle β, spacing of the leading-edges S, and the arrangement under various operating conditions. The performance of two rows of in-line and staggered arrayed vortex generators are also investigated. Experimental Reynolds number, Re, ranges from 700 to 26 800. The results indicate that under the present experimental conditions, the heat transfer enhancement of  = 12° is better than that of  = 20° with the highest local convective heat transfer coefficients 19.7% and 10.7% higher than that of the flat channel at Re = 1 300, and 23.2%, 18.33% at Re = 26 800, respectively. The optimal attack angle and spacing of the leading-edges for oblique-cut semi-elliptic cylinder shell vortex generators ( = 12°) are β = 60° and S = 20 mm with the highest local heat transfer coefficient and the pressure drop about 23.2% and 33.7 % higher than the flat channel at Re = 26 800. Due to the effect of the wake region, the heat transfer enhancement of two rows is weaker than the single row at low Reynolds. As the Reynolds number increases up to 4 000, the heat transfer enhancement of two rows is better than the single row with the highest local heat transfer coefficient about 14.4% higher than the single row vortex generators and 33.4% higher than the flat-channel at Re = 26 800. In addition, the results show that the vortices acting distance of oblique-cut semi-elliptic cylinder shell vortex generator is approximately between 250mm and 300 mm at β = 60°,  = 12°.*

Key words: Experimental investigation, Heat transfer enhancement, Pressure drop, Rectangular channel, Vortex generator