Parameters study and analysis of turbulent flow and heat transfer enhancement in narrow channel with discrete grooved structures

•Newly designed inclined discrete grooves (IDG) arranged in the same directions and alternate directions are presented.•The IDG with the smaller longitudinal pitches and larger transversal pitches provide higher heat transfer performance.•The empirical correlations for Nusselt number and friction factor are proposed to assist design activities. The influence of discrete grooved structures on heat transfer enhancement in a narrow channel has been investigated numerically. In the present work, three groove configurations including P-type grooves, V-type grooves and W-type grooves are considered with various geometrical parameters, four longitudinal groove-pitch ratios, three transversal groove-pitch ratios, three groove-depth ratios and five groove-inclined angles. The numerical results reveal that Nusselt number value for the P-type grooves is enhanced by 45.8–65.4% and friction factor for the P-type grooves is increased by 95.1–114.8% compared to plain duct with the Reynolds number range (Re) between 4016 and 10,709. To obtain an optimum thermal performance condition, the effect of geometrical parameters on the heat transfer and friction factor in the channel is examined. The results of parameters study show that the case of P-type grooves with ph=1.2, fh=2.6, eh=1, α=30° provides the best overall thermal performance factor (TPF) at Re=4016. Finally, empirical correlations evaluating the Nusselt number and friction factor of three groove configurations are also generated to assist design activities.