Hydro-thermal characteristics of laminar flow through a square duct having transverse ribs and helical screw-tape inserts

The hydro-thermal characteristics of transverse ribs combined with helical screw tape inserts in square duct are numerically investigated and compared the numerical findings with very little available experimental results. Moreover, the experimental data is available only with circular duct. No other cross-sectioned duct has ever been investigated. The motivation and novelty of the present work is to fill this hiatus. Finite volume method-based solver, ANSYS Fluent has been used for simulation. The uniform heat flux boundary condition has been imposed and a wide range of Prandtl number with five different fluids has been used for this investigation. This is never ever possible in a single experimental programme. Only numerical simulation can do the job and this is the inherent beauty of the present investigation. The results of experimental and computational findings proved that the present configuration produces good mixing and enhanced boundary layer separation. The results of the effect of rib height, rib pitch and screw tape parameter on Nusselt number and friction factor are presented. The numerical investigation has shown that Servotherm oil is the best fluid. The Nusselt number is increasing with increase in rib height and Reynolds number and it is decreasing with increase in rib pitch and screw tape parameter value. Also, the friction factor is increasing with increase in rib height and Reynolds number but the increment in Nusselt number is larger than the increment in friction factor. Therefore, the present fin geometry is recommended for industrial use.

Automated summary

This study numerically investigates the hydro-thermal characteristics of transverse ribs combined with helical screw tape inserts in square duct and compares the findings with limited experimental results. The results show that the present configuration produces good mixing and enhanced boundary layer separation. The Nusselt number and friction factor increase with an increase in rib height and Reynolds number, while they decrease with an increase in rib pitch and screw tape parameter value.