Abstract

The enhancement of heat transfer from the impinging jets can be reason of tens of parameters. In earlier studies, researchers have done numerous experiments or numerical runs to show the effect of each parameter individually. However, in recent decade some new methodologies, such as Design of Experiment (DoE) and Analysis of Variance (ANOVA) have been used to achieve more comparative parameter analysis and to optimize the number of experiments (or numerical runs). In this study, DoE and ANOVA methods are applied to an experimental impinging jet study. The jet geometry and roughness of impingement plate are the main considered parameters of this study. Beside them, effects of jet-to-surface distance (H) and radial distance (r) on the target surface are analyzed. The data runs are performed for a constant jet Reynolds number 20,000. The Taguchi DoE method is applied to the study in order to design the experiments. Totally 18 experiments are run base on the orthogonal array of L₁₈ (1⁶) (3³), and effects of each design parameter on heat transfer is found out by ANOVA. As a result, it is concluded that, the highest effect on Nusselt number is observed to be the radial distance (88%), while surface roughness has the effect in percentage of 8%. The contribution of jet geometry and jet-to-surface distance are much lower, as being 3% and 1%, respectively.

中文翻译：

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凹坑的粗糙表面布置方式和射流几何形状对射流传热的影响

摘要

来自撞击射流的热传递的增强可能是数十个参数的原因。在较早的研究中，研究人员已经进行了许多实验或数值模拟，以分别显示每个参数的效果。但是，近十年来，一些新方法，例如实验设计（DoE）和方差分析（ANOVA）已用于实现更多比较参数分析并优化实验次数（或数值运行）。在这项研究中，DoE和ANOVA方法被应用于实验性射流研究。冲击板的射流几何形状和粗糙度是该研究的主要考虑参数。在它们旁边，射流到表面的距离（H）和径向距离（r）在目标表面上进行分析。对于恒定射流雷诺数20,000执行数据运行。Taguchi DoE方法应用于研究以设计实验。基于L ₁₈（1 ⁶）（3 ³）的正交数组进行了总共18个实验，并且通过ANOVA找出了每个设计参数对传热的影响。结果，可以得出结论，对努塞尔数的最大影响是径向距离（88％），而表面粗糙度的影响百分比为8％。射流几何形状和射流到表面距离的贡献要低得多，分别为3％和1％。