Experimental investigation of a cross-flow heat exchanger with wing-type vortex generators

Abstract

In this study, heat and fluid flow in a plate-fin heat exchanger with wing-type convergent-divergent longitudinal vortex generators (CDLVGs) were studied experimentally. A cross-flow plate-type heat exchanger was designed and manufactured in the laboratory. Winglets were aligned with the angle of attack (β = 30°) positively and negatively to the main air flow direction, leading to eventually a better mixing phenomenon. Compared to the plate-fin geometry, the penalty of additional pressure drops of the other vortex generators was relatively insensitive to the change of the Reynolds number. The effects of the CDLVGs for various flow velocities on the cross-flow heat exchanger were investigated experimentally. Heat transfer experiments were performed under three different conditions. The highest heat transfer performance was found when the hot flow clack was half open and the cold flow clack was fully open in the second position. The correlations for the heat transfer coefficients and pressure drop characteristics were obtained as functions of the Reynolds number and the Prandtl number. The relationship between the effectiveness and the number of transfer units (ε-NTU) of the cross-flow heat exchanger were determined.