Local Nusselt number evaluation in the case of jet impingement

Kura, Tomasz; Fornalik-Wajs, Elżbieta; Wajs, Jan; Kenjereš, Saša

doi:10.1088/1742-6596/1101/1/012018

Cited by 6 publications

(17 citation statements)

References 10 publications

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“…In this paper, thermal and hydrodynamic analyses of jet impingement on flat and non-flat surfaces were presented. Both boundary conditions and scope of interest were based on [1][2][3][5][6][7][8]. Mesh and software configurations were determined by ERCOFTAC data [7][8].…”

Section: Discussionmentioning

confidence: 99%

“…Before analyzing arrays of jets, that impinge non-flat surfaces, it is important to define the influence of the surface shape on the flow behavior. In [6] Authors tried to define the critical curvature radius to orifice diameter ratio R/D, for which the curvature effect plays a role. It was concluded, that depending on the type of surface and mentioned ratio, the difference in heat transfer occurs between the particular non-flat and flat surface impingement.…”

Section: Flat Surface Validation Casementioning

confidence: 99%

“…Moreover, with increasing ratio, the values tended to vary lesssince the curvature of stagnation zone was almost negligible. However, [6] did not contained hydrodynamic data, which also is very important. In [6] it was noticed, that for ratio of surface curvature and orifice diameter equal to 4, the curvature effect is noticeable.…”

Section: Flat Surface Validation Casementioning

confidence: 99%

“…However, [6] did not contained hydrodynamic data, which also is very important. In [6] it was noticed, that for ratio of surface curvature and orifice diameter equal to 4, the curvature effect is noticeable. Therefore, this ratio was selected for representation in the following studies.…”

Section: Flat Surface Validation Casementioning

confidence: 99%

“…The following paper regards the analysis of single minijet that impinge various surfaces -flat, convex and concave. Their geometry was chosen in the basis of previous research [6], as well as data from [1][2][3]. While the available information for the flat case is generally broad, non-flat impingement is still not a popular and widely described scientific topic.…”

Section: Introductionmentioning

confidence: 99%

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Turbulence models impact on the flow and thermal analyses of jet impingement

et al. 2018

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Accurate numerical reconstruction of heat and mass transfer processes in particular applications, such a jet impingement, is difficult to obtain even with the use of modern computational methods. In the proposed paper, the flow and thermal phenomena occurring during single minijet impingement on the flat, concave and convex, heated surfaces were considered. Problem of impingement on non-flat surface, still not common and purely described in the literature, can be of big importance in engineering applications, such as the heat exchangers. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted with the OpenFOAM software. Focus was placed on the proper model construction, in which turbulence and boundary layer modelling was crucial, due to their significance in the heat transfer processes. Analysis of results obtained by RANS models focused mostly on the comparison of turbulent and hydrodynamics parameters.

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Section: Discussionmentioning

confidence: 99%

Section: Flat Surface Validation Casementioning

confidence: 99%

Section: Flat Surface Validation Casementioning

confidence: 99%

Section: Flat Surface Validation Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Turbulence models impact on the flow and thermal analyses of jet impingement

et al. 2018

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Heat transfer intensification by jet impingement – numerical analysis using RANS approach

et al. 2019

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Jet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically complex. Therefore the numerical analysis is necessary to understand the phenomena, especially in the range of turbulent flow. The well-known and accurate method is Reynolds Averaged Navier-Stokes (RANS) approach. However, depending on the applied turbulence model, various results can be obtained. The reason is that the jet impingement strongly depends on the complex boundary layer effects and their resolving is still challenging for RANS models and until now it is their weakest point. In the paper, the hydrodynamic and thermal, numerical results of jet impingement are presented, depending on selected RANS based models. The aim was to indicate their ability to anticipate the turbulence parameters.

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Thermal and Hydrodynamic Phenomena in the Stagnation Zone—Impact of the Inlet Turbulence Characteristics on the Numerical Analyses

et al. 2020

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One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason, but their accurate numerical analysis is still very challenging. The authors’ aim was to construct the numerical model which can represent the real phenomena with good or very good accuracy. Starting with an analysis of single jet and obtaining the agreement with experimental data, it will be possible to extend the model towards the whole minijets heat exchanger. The OpenFOAM software, Bracknell, UK was used for that purpose, with our own implementation of the ζ-f turbulence model. The most difficult area to model is the stagnation region, where the thermal effects are the most intensive and, at the same time, strongly affected by the conditions in the pipe/nozzle/orifice of various size (conventional, mini, micro), from which the jet is injected. In the following article, summary of authors’ findings, regarding significance of the velocity profile and turbulence intensity at the jet place of discharge are presented. In addition, qualitative analysis of the heat transfer enhancement is included, in relation to the inlet conditions. In the stagnation point, Nusselt number differences reached the 10%, while, in general, its discrepancy in relation to inlet conditions was up to 23%.

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Local Nusselt number evaluation in the case of jet impingement

Cited by 6 publications

References 10 publications

Turbulence models impact on the flow and thermal analyses of jet impingement

Turbulence models impact on the flow and thermal analyses of jet impingement

Heat transfer intensification by jet impingement – numerical analysis using RANS approach

Thermal and Hydrodynamic Phenomena in the Stagnation Zone—Impact of the Inlet Turbulence Characteristics on the Numerical Analyses

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