Effects of a triangular guide rib on flow and heat transfer in a turbulent jet impingement on an asymmetric concave surface

Abstract

In this study, a triangular guide rib (TGR) is designed with the aim of enhancing the heat transfer rate by accelerating a jet impinging downward on an asymmetric concave surface with curvature radii of 8 cm (Cr = 0.15) and 12 cm (Cr = 0.1). An infrared thermometer camera is employed to measure the temperature distribution in the steady-state condition. Predicted Nusselt number profiles by the renormalization group k–ε turbulent model go well with the experimental data. An equilateral triangular rib with each side measuring 12 mm (D/2) is placed in the stagnation region to investigate the effects of the TGR on flow and heat transfer of the asymmetric concave surface. This investigation is carried out for three different Reynolds numbers: 23 000, 35 000, and 50 000. The acceleration of the impinging jet due to the TGR creates a horseshoe-shape in the zone of high Nusselt number values. Numerical results show that the TGR provides higher averaged Nusselt numbers compared to a smooth concave surface.

Numerical Investigation and Parameter Sensitivity Analysis on Flow and Heat Transfer Performance of Jet Array Impingement Cooling in a Quasi-Leading-Edge Channel

“…The maximum prediction deviations of the RNG k-ε and standard k-ω turbulence models are about 17.79% and 15.03%, respectively. While the simulation values of local Nu calculated by the SST k-ω turbulence model are very close to the experimental values [25][26][27][28], the maximum prediction deviation of the SST k-ω turbulence model is about 6.36%. The above results show that the numerical method with the SST k-ω turbulence model used in this study can accurately and reliably simulate the heat transfer characteristics of the jet impinging on the semi-cylindrical concave wall.…”

“…They pointed out that the SST k-ω turbulence model can capture the distribution features of static pressure and heat transfer coefficient on the concave target wall well. Then, they [26,27] studied the influence of elliptical pin-fins on the flow and heat transfer performance of a circular hole jet impinging on a concave target wall; the results again proved the accuracy of the SST k-ω turbulence model in predicting the heat transfer performance of a jet impinging on a concave target wall. Huang et al [28] reported that the modified SST k-ω turbulence model with the curvature correction can significantly improve the prediction accuracy of flow and heat transfer behaviors for the jet impinging on the concave target wall.…”

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

“…Analysis was performed by varying geometric parameters of the relative protrusion diameter-protrusion height ratio (dpr/epr), and a thermo-hydraulic parameter's maximum value of 3.01 was achieved. An experimental and numerical study was performed by Hadipour et al [63] to investigate the effect of a triangular guided rib (TGR) on thermal and flow characteristics of turbulent jet impingement on a concave surface. The asymmetric concave surface had curvature radii of 8 cm and 12 cm.…”