The Laws of Distribution of the Values of Turbulent Thermo-physical Characteristics in the Volume of the Flows of Heat Carriers Taking into Account the Surface Forces

Bіlonoga, Yuriy; Maksysko, Oksana

doi:10.18280/ijht.370101

Cited by 5 publications

(42 citation statements)

References 17 publications

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“…Based on our works [29][30][31][32][33][34], we concluded that our proposed model of contacting metal surfaces with regard to their the binding energy and surface energy [29][30][31], as well as consideration of the movement of heat-transfer fluids near the metal walls of the heat exchange equipment with taking into account surface forces [32][33][34], has the right to exist. Based on this, we set ourselves the following tasks in this work:…”

Section: Problem Formulationmentioning

confidence: 90%

“…At the same time, the value 0 1 P CK  reflects the speed of thermal movement at the molecular level, having the dimension m/s, and the value V is the linear speed of movement of the coolant with the nanoparticles at T mode. We also remind that the transitional viscosity of a fluid, the value of which we derived in previous works [33,34], is the viscosity at the interface of LBL and turbulent flow, having dimension (Pa.s) and calculated by formula 3, and dimensionless turbulent number is the ratio of turbulent to transition viscosity (4) In addition, the dimensionless number Bl is (5) [33,34].…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

“…The average diameter of small nanoparticles is actually commensurate with the size of the molecules of the base fluid, and therefore this statement is quite acceptable and justified. However, in this work we attempted to circumvent these warnings, using the concept of turbulent viscosity and thermal conductivity of liquid coolants, which we followed in the calculation and selection of heat exchangers in the works [33,34].…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

“…Based on our works [32][33][34], having written the value of turbulent viscosity in the central part of the coolant flow, we obtain 2:…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

“…In particular, in the work [34], we presented the final formula for calculating the turbulent number Blturb. which has the form (6):…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

See 4 more Smart Citations

A New Universal Numerical Equation and a New Method for Calculating Heat-Exchange Equipment Using Nanofluids

Bіlonoga¹,

Stybel²,

Maksysko³

et al. 2020

IJHT

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This article analyzes the vast material of works devoted to the use of nanofluids in heat exchange equipment. It is proved that the use of the classical theories and equations for calculating the viscosities and thermal conductivities of nanofluids is not correct, since it does not coincide with the experimental results of most independent authors. A model of the chaotic motion of a nanoparticle is presented taking into account surface tension forces in a liquid coolant. The experimental results of the work of Malaysian and Iran authors on the effect of TiO2 nanoparticles with a concentration of 0.5%; 1.0% and 1.5% in the main liquid solution of ethylene glycol (EG) in water in a volume ratio of 40:60% in terms of heat transfer coefficient are compared with our theoretical studies. The results of the experiments presented in: an increase in heat transfer coefficients by 9.72%, 22.75%, 28.92% for 1.5% volume concentration of TiO2 nanoparticles at a coolant temperature of 30℃, 50℃, 70℃, respectively. Our theoretical result: increase in the obtained heat transfer coefficients by 9.79%, 22.22%, 29.09% according to our formulas (9, 10, 15) for calculating turbulent viscosities and thermal conductivities, which takes into account the effect of surface tension forces on the total flow of nanofluids in the channels of heat exchange equipment. A new method for calculating heat exchange equipment using nanofluids is presented, taking into account the action of surface tension forces, as well as predetermining the calculation of turbulent viscosities and thermal conductivity of nanofluids. A theoretical calculations a plate heat exchangers for a technological task performed by classical and new method is presented. Similar results were obtained, which differ by about 0.5 of a percent. The plate heat exchanger was calculated using a new method using TiO2 nanoparticles in water and in a mixture of EG in water in a ratio of 40:60%, as well as when pumpkin vegetable oil was added to milk with the optimal concentration.

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Section: Problem Formulationmentioning

confidence: 90%

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

“…Based on our works [32][33][34], having written the value of turbulent viscosity in the central part of the coolant flow, we obtain 2:…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

“…In particular, in the work [34], we presented the final formula for calculating the turbulent number Blturb. which has the form (6):…”

Section: Analysis Of the Forces Acting On The Nanoparticle Based On mentioning

confidence: 99%

See 3 more Smart Citations

A New Universal Numerical Equation and a New Method for Calculating Heat-Exchange Equipment Using Nanofluids

Bіlonoga¹,

Stybel²,

Maksysko³

et al. 2020

IJHT

Self Cite

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Substantiation of a New Calculation and Selection Algorithm of Optimal Heat Exchangers with Nanofluid Heat Carriers Taking into Account Surface Forces

Bіlonoga¹,

Stybel²,

Maksysko³

et al. 2021

IJHT

Self Cite

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The article examines the problem of correct, accurate calculation and optimization of the choice of heat exchange equipment when using nanofluid heat carriers for heat treatment of liquid food products using milk as an example. To solve this problem, the motion of a metal nanoparticle in a turbulent flow of the main coolant was simulated using the methods of similarity theory, taking into account the action of surface forces in the laminar boundary layer. New formulas are obtained for a qualitative assessment of the average thickness of the laminar boundary layer that appears around a turbulently moving metal nanoparticle. A number of qualitative correlations with other literature sources that explain the behavior of nanoparticles in a turbulent liquid medium are shown. A new approach to heat transfer processes is considered taking into account the theory of J. Boussinesq, which gives an idea of turbulent viscosity and thermal conductivity, as well as a comparison of the resistance forces to the surface forces. The physical meaning of the previously obtained by us new similarity numbers Bl and Blturb. and their application in our new numerical equation for calculating heat exchangers is considered, and a new express method for evaluating the efficiency of using nanofluid heat carriers is proposed. The proposed method of express calculation shows that the mixture H2O + EG (60:40) improves the heat exchange properties of water by + 12.86%, and the mixture (H2O + EG (60:40) + 1.5% TiO2) and (milk + 0.5% pumpkin seed oil) - by + 16.75%, which corresponds to the experiments and our calculations, and the well-known express method based on classical numerical equations shows a deterioration by - 4.5% and, accordingly, by – 1.2%.

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Improvement of the Method of Calculating Heat Transfer Coefficients Using Glycols Taking into Account Surface Forces of Heat Carriers

Bilonoga,

Atamanyuk,

Stybel

et al. 2023

ChChT

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This study compares the classic calculating method of the heat transfer coefficients of the shell-and-tube heat exchanger tubes using the classic Nusselt, Reynolds, and Prandtl similarity numbers with a new method that takes into account the coefficients of surface tension of heat carriers, their transitional, turbulent viscosity and thermal conductivity, as well as the average thickness of the laminar boundary layer (LBL). The classic method shows a better efficiency of water as a heat carrier com-pared to a 45% aqueous solution of propylene glycol. Instead, the new calculation method shows that a 45% aqueous solution of propylene glycol at the same Rey-nolds numbers has higher heat transfer coefficients com-pared to water in the temperature range of 273–353 K. We divided the "live cross-section" of the flow of the liquid coolant into a medium-thick LBL, where the Fourier equation of thermal conductivity is applied, and into its turbulent part, where the equation of thermal conductivity with turbulent thermal conductivity is also applied. A new formula (14) is proposed for calculating the average thickness of the LBL based on the radius of the "live cross-section" of the coolant flow, as well as the Blturb similarity number obtained by us in previous works. A new formula (15) is also proposed for calculating the heat transfer coefficient, which includes the transitional and turbulent thermal conductivity of the corresponding zones of the flow "live section", as well as the average thickness of the LBL.

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The Laws of Distribution of the Values of Turbulent Thermo-physical Characteristics in the Volume of the Flows of Heat Carriers Taking into Account the Surface Forces

Cited by 5 publications

References 17 publications

A New Universal Numerical Equation and a New Method for Calculating Heat-Exchange Equipment Using Nanofluids

A New Universal Numerical Equation and a New Method for Calculating Heat-Exchange Equipment Using Nanofluids

Substantiation of a New Calculation and Selection Algorithm of Optimal Heat Exchangers with Nanofluid Heat Carriers Taking into Account Surface Forces

Improvement of the Method of Calculating Heat Transfer Coefficients Using Glycols Taking into Account Surface Forces of Heat Carriers

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