High Performance Tubular Heat Exchanger with Minijet Heat Transfer Enhancement

Wajs, Jan; Mikielewicz, Dariusz; Fornalik-Wajs, Elżbieta; Bajor, Michał

doi:10.1080/01457632.2018.1442369

Cited by 13 publications

(20 citation statements)

References 29 publications

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“…Therefore, the crossflow role cannot be neglected in the case of the proposed solution of the heat exchangers. An theoretical and experimental analyses of the prototype constructions [27,28] revealed that the innovative idea of jet technology application facilitates in particular the heat transfer at low fluid flow rates and/or with a small temperature difference between fluids. This paper presents further research conducted on the intensification of heat transfer and reduction of the hydraulic resistance in a patented design of the minijet heat exchanger [24], for a future optimization of the construction.…”

Section: Minijets Heat Exchanger (Mjhe)mentioning

confidence: 99%

Thermal-Hydraulic Studies on the Shell-and-Tube Heat Exchanger with Minijets

2019

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In this paper a patented design of a heat exchanger with minijets, with a cylindrical construction is presented. It is followed by the results of its systematic experimental investigations in the single-phase convection heat transfer mode. Based on these results, validation of selected correlations (coming from the literature) describing the Nusselt number was carried out. An assessment of the heat exchange intensification level in the described heat exchanger was done through the comparison with a shell-and-tube exchanger of a classical design. The thermal-hydraulic characteristics of both units were the subjects of comparison. They were constructed for the identical thermal conditions, i.e., volumetric flow rates of the working media and the media temperatures at the inlets to the heat exchanger. The experimental studies of both heat exchangers were conducted on the same test facility. An increase in the heat transfer coefficients values for the minijets heat exchanger was observed in comparison with the reference one, whereas the generated minijets caused greater hydraulic resistance. Experimentally confirmed intensification of heat transfer on the air side, makes the proposed minijets heat exchanger application more attractive, for the waste heat utilization systems from gas sources.

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Section: Minijets Heat Exchanger (Mjhe)mentioning

confidence: 99%

Thermal-Hydraulic Studies on the Shell-and-Tube Heat Exchanger with Minijets

2019

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“…In Table 3, locations of turbulence kinetic energy maxima are listed, in relation with orifice diameter D. They were established for flat and non-flat cases in the same manner, as data from Figure 8. Differences between each case existit is an important aspect to mention, because it may influence the results when the jets array impingement occurs, such as in [1][2][3]. Multiple jets might strongly interfere with each other.…”

Section: Flat Surface Validation Casementioning

confidence: 99%

“…It was being used in the cooling systems of electronics or in some metallurgical processes. Recently, however, it was proposed in the novel construction of cylindrical heat exchanger [1], which resulted in very promising values of transferred heat rates and lower than in other similar devices hydraulic resistance [2][3].…”

Section: Introductionmentioning

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%

“…While the available information for the flat case is generally broad, non-flat impingement is still not a popular and widely described scientific topic. Correlations do not exist, which can be used in the problems regarded in [1][2][3]. The goal of paper was to identify the turbulence model impact on the results and describe the differences between impingement on various surfaces -since such knowledge would be essential to correctly analyze arrays of minijets, existing for example in heat exchangers [1][2][3].…”

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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