Analysis of heat transfer and fluid flow of a slot jet impinging on a confined concave surface with various curvature and small jet to target spacing

Abstract

Purpose This study aims to focus on the surface curvature, jet to target spacing and jet Reynolds number effects on the heat transfer and fluid flow characteristics of a slot jet impinging on a confined concave target surface at constant jet to target spacing. Design/methodology/approach Numerical simulations are used in this research. Jet to target spacing, H/B is varying from 1.0 to 2.2, B is the slot width. The jet Reynolds number, Rej, varies from 8,000 to 40,000, and the surface curvature, R2/B, varies from 4 to 20. Results of the target surface heat transfer, flow parameters and fluid flow in the concave channel are performed. Findings It is found that an obvious backflow occurs near the upper wall. Both the local and averaged Nusselt numbers considered in the defined region respond positively to the Rej. The surface curvature plays a positive role in increasing the averaged Nusselt number for smaller surface curvature (4-15) but affects little as the surface curvature is large enough (> 15). The thermal performance is larger for smaller surface curvature and changes little as the surface curvature is larger than 15. The jet to target spacing shows a negative effect in heat transfer enhancement and thermal performance. Originality/value The surface curvature effects are conducted by verifying the concave surface with constant jet size. The flow characteristics are first obtained for the confined impingement cases. Then confined and unconfined slot jet impingements are compared. An ineffective point for surface curvature effects on heat transfer and thermal performance is obtained.

Cooling structure design of gas turbine blade by using multi-level highly efficient design platform

“…(3) Addition of special structures; Some structures, i.e. ribs, 19 pin-fins, 20 dimples, 21 impingement holes, 22 and film holes, 23 are usually placed in the cooling passage. In this part, new structures can be quickly generated by input parameters.…”

Experimental and Computational Study on Effect of Vanes on Heat Transfer and Flow Structure of Swirling Impinging Jet

“…They reported that the cylindrical cavity enhances the heat transfer rate of the heat sink and the horse shoe vortex produced near the cavity edge improves the heat transfer performance. Qiu et al (2019) focused on heat transfer on flow characteristics of slotted jet on concave surface by varying the Jet to target spacing (H/B ratio =1-2.2), surface curvature (R/B = 4-20) with Reynolds number range of 8000 and 40000. Their results reveal that Nusselt number is increasing at smaller curvature (4-15) and it decreases when the curvature is larger (>15).…”

On heat transfer and flow characteristics of jets impinging onto concave surface with varying bleeding arrangements

“…Due to its high potential in enhancing local heat transfer, jet impingement has been widely used in turbine thermal load components, especially for the highest heat load portionthe blade leading edge, which directly suffers hot gas from combustor (Kwak and Han, 2002). Many significant works spent much efforts on the effects of jet Reynolds number, jet nozzle configuration, jet-to-target spacing, target arrangement and jet inclination angle on single jet impinging onto a confined or an unconfined concave or convex surface (Yang et al, 1999;Rahman et al, 2010;Qiu et al, 2019;Cornaro et al, 1999;Luo et al, 2016;Lee et al, 2007;Yang and Hwang, 2004).…”

“…Many significant works spent much efforts on the effects of jet Reynolds number, jet nozzle configuration, jet-to-target spacing, target arrangement and jet inclination angle on single jet impinging onto a confined or an unconfined concave or convex surface (Yang et al , 1999; Rahman et al , 2010; Qiu et al , 2019; Cornaro et al , 1999; Luo et al , 2016; Lee et al , 2007; Yang and Hwang, 2004).…”