In this study, jet impingement cooling on a rib-roughened surface has been investigated experimentally. The aim of this study is to investigate the effect of extended jet holes on the heat transfer performance and flow characteristics of the jet impingement cooling on a rib-roughened surface. The studies have been conducted under turbulent flow condition (16,250 ≤ Re_j ≤ 32,500). Transient Liquid Crystals (TLC) method has been employed to investigate the average and local Nusselt number (Nu) distributions on the surface of interest. Six inline arrays of jet impingement configuration have been examined as the jet impingement cooling system. Jet holes were extended towards the target surface with the nozzles. Various dimensionless nozzles to the target surface gaps (G_j/D_j = 1.0, 2.0, 3.0, 4.0 and 5.0) have been investigated. Rectangular cross-sectional ribs were located on the surface of interest for the augmentation of heat transfer. Experimental studies were conducted on the dimensionless rib height as H_r/D_j = 0.42. In addition, numerical studies were carried out to investigate the flow and heat transfer characteristics. The effect of various dimensionless rib heights (H_r/D_j) on convective heat transfer performance has also been investigated numerically. SST k-ω with low-Re correction turbulence model was used for solving turbulence equations. Average and local Nu number distributions, flow characteristics and Performance Evaluation Criterion (PEC) were examined in detail. Results were compared with the orifice plate (G_j/D_j = 6.0) jet impingement configuration. Results showed that SST k-ω turbulence model accurately reveals the experimental data. Application of extended jet holes is a feasible method for practical application of the jet impingement cooling, especially at relatively low dimensionless nozzle gap (G_j/D_j$\le$4.0). Furthermore, improperly designed rib height has been found to diminish heat transfer performance.

在这项研究中，已经对通过肋骨粗糙的表面进行射流冲击冷却进行了实验研究。这项研究的目的是研究延伸的射流孔对肋表面粗糙的射流冲击冷却的传热性能和流动特性的影响。该研究已湍流条件（16,250下进行 ≤重新_Ĵ  ≤  32,500）。瞬态液晶（TLC）方法已被用来研究平均和局部Nusselt数（Nu）在目标表面上的分布。已经检查了六个串联的射流冲击配置阵列作为射流冲击冷却系统。喷嘴用喷嘴向目标表面延伸。已经研究了到目标表面间隙的各种无量纲喷嘴（G _j / D _j  = 1.0、2.0、3.0、4.0和5.0）。矩形横截面肋位于目标表面上，以增强传热。对无因次肋骨高度H _r / D _j进行了实验研究 = 0.42。另外，进行了数值研究以研究流动和传热特性。数值上研究了各种无因次肋高（H _r / D _j）对流传热性能的影响。使用具有低Re校正湍流模型的SSTk-ω来求解湍流方程。详细检查了平均和局部Nu数分布，流动特性和性能评估标准（PEC）。将结果与孔板（G _j / D _j  = 6.0）的射流冲击配置进行了比较。结果表明SSTk-ω湍流模型准确地揭示了实验数据。延长喷孔的应用是实际应用喷流冷却的可行方法，尤其是在相对较小的无量纲喷嘴间隙（G _j / D _j$\le$4.0）。此外，已经发现，设计不当的肋高度会降低传热性能。