Parametric study of a fluidic oscillator for heat transfer enhancement of a hot plate impinged by a sweeping jet

Abstract

• CFD and experimental studies are conducted on the heat transfer of fluidic oscillators. • Effect on the heat transfer rate due to new geometrical changes is studied. • Experimental study was conducted to verify the numerical results for the fluidic oscillator. • Heat transfer rate was increased by 140% when removing the external diffuser. • Heat transfer was decreased when increasing the distance ratio and divergence angle. Many studies have looked at the effects of various geometrical parameters of fluidic oscillators on the heat transfer rate of a hot plate impinged by a sweeping jet. In this research, Ansys-Fluent software was used to solve two-dimensional Unsteady Reynolds-Averaged Navier-Stokes ( URANS ) equations with a k-ω (SST) turbulence model to study the effect on the heat transfer rate of a hot plate due to some new geometrical changes, such as removing the external diffuser, changing the divergence angle of the external diffuser, and changing the distance from the outlet throat to the hot plate. An experimental setup was provided to verify the numerical results for the fluidic oscillator with an external diffuser. To measure the temperature inside and near the surface, 22 thermocouples were used inside a thick hot plate, which was impinged by a sweeping jet. Three distance ratios ( X/D = 4.5, 5.5 and 7.5) and four divergence angles ( θ = 180°, 50°, 70°, and 90°) were numerically analyzed as the geometrical parameters at Reynolds number of 30,000, 60,000, and 120,000. The results revealed that the heat transfer rate increased by 140% when removing the external diffuser at X/D = 4.5 and Re = 60,000, while it decreased when increasing the distance ratio and divergence angle.