Instability of a vapor layer on a vertical surface at presence of nanoparticles

Авраменко, А. А.; Shevchuk, Igor V.; Moskalenko, A. A.; Lohvynenko, Petro; Kovetska, Yu.Yu.

doi:10.1016/j.applthermaleng.2018.04.113

Cited by 14 publications

(3 citation statements)

References 36 publications

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“…( 12) for the film thickness looks as A solution of this equation under the boundary condition ( 26) brings the following transcendental equation for the film thickness (58 67) and by Cheng and Verma (1981), who considered also nonlinear effects (advection and convection). The differences between the present calculations using a linear approach and the results of the nonlinear approach obtained by Avramenko et al (2018) increase with the decreasing Jacob numbers.…”

Section: Condition Q W = Constcontrasting

confidence: 58%

“…Similar problems of convective heat and mass transfer at film boiling and condensation of nanofluid on a vertical wall in the approximation of the boundary layer with free outer flow were considered by Avramenko et al (2014Avramenko et al ( , 2015aAvramenko et al ( , b, c, 2016Avramenko et al ( , 2018. The authors studied the influence of physical properties of the nanofluid and outer flow parameters on the behavior of velocity and temperature profiles, as well on the heat transfer coefficients.…”

Section: Introductionmentioning

confidence: 97%

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Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

et al. 2020

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The paper presents results of the modelling of heat transfer at film boiling of a liquid in a porous medium on a vertical heated wall bordering with the porous medium. Such processes are observed at cooling of high-temperature surfaces of heat pipes, microstructural radiators etc. Heating conditions at the wall were the constant wall temperature or heat flux. The outer boundary of the vapor film was in contact with moving or stationary liquid inside the porous medium. An analytical solution was obtained for the problem of fluid flow and heat transfer using the porous medium model in the Darcy–Brinkman and Darcy–Brinkman–Forchheimer approximation. It was shown that heat transfer at film boiling in a porous medium was less intensive than in the absence of a porous medium (free fluid flow) and further decreased with the decreasing permeability of the porous medium. Significant differences were observed in frames of both models: 20% for small Darcy numbers at Da < 2 for the Darcy–Brinkman model, and 80% for the Darcy–Brinkman–Forchheimer model. In the Darcy–Brinkman model, depending on the interaction conditions at the vapor–liquid interface (no mechanical interaction or stationary fluid), a sharp decrease in heat transfer was observed for the Darcy numbers lower than five. The analytical predictions of heat transfer coefficients qualitatively agreed with the data of Cheng and Verma (Int J Heat Mass Transf 24:1151–1160, 1981) though demonstrated lower values of heat transfer coefficients for the conditions of the constant wall temperature and constant wall heat flux.

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Section: Condition Q W = Constcontrasting

confidence: 58%

Section: Introductionmentioning

confidence: 97%

Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

et al. 2020

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“…The obtained fluids are called nanofluids, which are suspensions of nanoparticles in main working fluids. Using nanofluids can eliminate disadvantages of conventional fluids because of their superior thermal conductivity in comparison with common fluids [8][9][10][11][12]. Particle ratio, particle size, particle shape and base fluid properties are the major parameters that affect nanofluid thermal behavior [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

A comparative study on utilizing hybrid-type nanofluid in plate heat exchangers with different number of plates

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et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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Different methods have been utilized to enhance the thermal efficiency of the heat exchangers (HEs). A widely used method to upgrade the thermal efficiency of HEs is upgrading the thermal properties of working fluid by utilizing nanoparticles. In this study, Al 2 O 3 and CuO have been utilized to prepare Al 2 O 3-CuO/water hybrid nanofluid. Accordingly, Al 2 O 3 and CuO nanoparticles have been mixed into the water with 1% (50:50) weight concentration. The main objective of this work is testing the prepared hybrid nanofluid in plate-type HEs (PHEs) with 8, 12 and 16 plates to determine the influence of number of plates on heat transfer improvement by hybrid nanofluid. Experimental findings of the present study demonstrated that utilizing Al 2 O 3-CuO/water hybrid-type nanofluid in the PHE enhanced thermal efficiency notably in comparison with singletype nanofluids. Using this hybrid nanofluid increased the thermal performance in all PHEs with different number of plates. However, it is observed that increasing number of plates led to more increment in thermal performance by utilizing hybrid nanofluid. The highest increment in overall heat transfer coefficient was obtained as 12%, 19% and 20% in PHEs with eight, 12 and 16 plates, respectively. In addition, the highest enhancement in effectiveness was achieved as 10%, 11.7% and 16% in PHEs with eight, 12 and 16 plates, respectively. Keywords Plate heat exchanger • Hybrid nanofluid • Al 2 O 3-CuO/water • Performance List of symbols A Total heat transfer area (m 2) C Heat capacity rate (W/K) c p Specific heat capacity (J/kg K) D h Hydraulic diameter (m) f Friction factor

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