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Increased industrial development and demand for heat exchangers with efficient heat transfer are urgently needed. The efficiency of the heat exchanger can be achieved by increasing the rate of heat transfer. Increasing the rate of heat transfer can be performed by installing vortex generators on the surface. The longitudinal vortex generated by the vortex generators enhances heat transfer from the surface to the fluid. In this study, the heat transfer improvement was investigated experimentally in a rectangular channel. To achieve the aim of this study, six heated tubes with and without vortex generators with and without holes were installed in the channel. The number of pairs of VGs varied from one to three pairs with variations in flow velocity from 0.4 m/s to 2 m/s at intervals of 0.2 m/s. The effect of holes on the performance of Convex Delta Winglet Pairs (CxDWP) was evaluated with (j/j0)/(f/f0) as performance evaluation criteria (PEC). From the experimental results, it can be observed that the PEC of CxDWP three pairs with holes is 27% higher than that of CxDWP at Reynolds number 8,700.

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