2D PIV analysis of the flow dynamics of multiple jets impinging on a complex moving plate. (1st June 2022)

• Record Type: Journal Article
• Authors: Barbosa, Flavia V.; Teixiera, Senhorinha F.C.F.; Teixeira, José C.F.
• Is Part Of: International journal of heat and mass transfer. Volume 188(2022)
• Publication Date: 2022-06-01
• Subjects: Complex dynamic surface -- Heat transfer correlation -- Multiple jet impingement -- PIV -- Taguchi method; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2022.122600
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: The multiple jet impingement configuration that enhances the heat transfer is Re = 5000, H/D = 2, S/D = 3. A staggered configuration increases the flow turbulence intensity for low H/D . The non-flat plate increases the local heat transfer due to flow recirculation induced in the vicinity of the step. Even for low surface-to-jet velocity ratios ( Vs ), complex flow interactions are identified leading to an increase of the average Nusselt number. Correlations for both static and dynamic plates are determined and present good predictions with a reduced deviation from the measured data. Abstract: The enhancement of the multiple jet impingement process relies on several geometrical and flow parameters which highly influence the heat transfer over the target plate. Therefore, the detailed analysis of the effect of these parameters on multi-jet flow dynamics and heat transfer is of paramount importance. To conduct this study, a Design of Experiment (DoE) based on Taguchi's method is implemented to optimize the number of experiments and provide a comparative parameter analysis. This method is applied with the goal of optimizing the process for the maximum Nusselt number and the best configuration for both static and dynamic plates is obtained for a Reynold number of 5000, a nozzle-to-plate distance ( H/D ) of 2, and a jet-to-jet spacing ( S/D ) equal to 3. Even if the effect of the jet pattern and plate geometry is considered negligible compared with these factors, staggered jet's configuration and non-flat plate seem to enhance the heat transfer over the surface. To complement this analysis, PIV measurements are conducted in order to characterize the jet's flow and to validate the suitability of Taguchi's method for the study of complex multiple jet impingement processes. The results demonstrated that even for low surface-to-jet velocity ratios ( Vs ), complex flow interactions are identified leading to an increase of the average Nusselt number. From the experiments, the optimized configuration is validated. This study provided relevant data, mainly for the dynamic surface case, and new correlations for both static and moving plates are presented.