Wyniki wyszukiwania - BazTech

1

Mixed convective flow with variable viscosity and variable thermal conductivity in a channel in the presence of first order chemical reaction with heat generation or absorption

Shobha K. C., Biradar Mahadev, Mallikarjun B Patil

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 1

91--102

EN

A study has been made on the flow and heat transfer of a viscous fluid in a vertical channel with first order chemical reaction and heat generation or absorption assuming that the viscosity and thermal conductivity are dependent on the fluid temperature. The temperature of the walls is maintained constant. Under these assumptions, the governing balance equations of mass, momentum and energy are formulated. The dimensionless forms of the governing equations are coupled and non-linear, which cannot be solved analytically and therefore require the use of the Runge-Kutta fourth order along with shooting technique. Graphs for velocity and temperature under different values of parameters involved are plotted and discussed. The skin friction and Nusselt number on the channel walls are also computed and discussed. Furthermore, the investigation found that variable viscosity and variable thermal conductivity enhance the velocity and temperature of the flow.

2

Effects of non-uniform heat generation /absorption and radiation on hydromagnetic dissipative flow over a porous nonlinear stretching surface with heat and mass fluxes

Anjali Devi S. P., Agneeshwari M.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 4

36--52

EN

Forced convective heat and mass transfer flow of hydromagnetic, radiating and dissipative fluid over a porous nonlinear stretching sheet in the presence of non-uniform heat generation/absorption is investigated numerically. The system of nonlinear partial differential equations governing the physical problem is reduced to nonlinear ordinary differential equations by means of suitable similarity transformations and are solved numerically using Nachtsheim Swigert shooting iteration scheme together with fourth order Runge Kutta method. The effects of various physical parameters on velocity, temperature and concentration distributions are depicted graphically. The important findings of this study exhibited that the effect of non-uniform heat generation/absorption parameter and radiation parameter have significant role in controlling thermal boundary layer thickness and temperature. Numerical values of the skin friction coefficient, temperature and concentration at the wall are shown in a tabula form. A comparison is made with previously published data which results in good agreement.

3

Fractional heat conduction in an infinite rod with heat absorption proportional to temperature

Povstenko Y., Klekot J.

Scientific Issues of Jan Długosz University in Częstochowa. Mathematics

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2017

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Vol. 22

61--71

EN

The one-dimensional time-fractional heat conduction equation with heat absorption (heat release) proportional to temperature is considered. The Caputo time-fractional derivative is utilyzed. The fundamental solutions to the Cauchy and source problems are obtained using the Laplace transform with respect to time and the exponential Fourier transform with respect to the spatial coordinate. The numerical results are illustrated graphically.

4

The fundamental solutions to the central symmetric time-fractional heat conduction equation with heat absorption

Povstenko Y., Klekot J.

Journal of Applied Mathematics and Computational Mechanics

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2017

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Vol. 16, nr 2

101--112

EN

The time-fractional heat conduction equation with heat absorption proportional to temperature is considered in the case of central symmetry. The fundamental solutions to the Cauchy problem and to the source problem are obtained using the integral transform technique. The numerical results are presented graphically.

5

Effect of Biopolishing On Warm–Cool Feeling of Knitted Fabric: A Subjective and An Objective Evaluations

Mangat A., Hes L., Bajzik V.

Autex Research Journal

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2017

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Vol. 17, no. 2

95--102

EN

Soft and clean surface of fabric without any floating fibers is one of the factors important for better marketing of clothing. The most common method for having such clean fabric surface is the removal of protruding (floating) fiber from the surface of the fabric. Many studies have proved that enzymatic treatment, commonly called biopolishing, removes the floating fibers from the surface of fabric and gives a smooth surface to the fabric. This study is an effort to assess and measure the impact of biopolishing of knitted fabric through objective and subjective evaluation on warm-cool feeling of fabric because of change in surface profile of the fabric. For testing purposes, 31 knitted fabric samples of various kinds were produced. Alambeta has been used for measuring thermal absorptivity values of fabric. Thermal absorptivity is an indicator of warm-cool feeling. For subjective evaluation, a group of 30 people were asked to give their opinion about warm-cool feeling. Both subjective and objective assessments confirm that biopolishing has a significant impact on warm-cool feeling. Fabric gives cool feeling after biopolishing. This study explores that clean surface will have higher thermal absorptivity and will give cool feeling when it will be touched by human skin.

6

MHD natural convection flow past an impulsively moving vertical plate with ramped wall temperature in the presence of thermal diffusion with heat absorption

Seth G. S., Ansari Md. S.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 1

199-215

EN

Hydromagnetic natural convection flow of a viscous incompressible electrically conducting and heat-absorbing fluid past an impulsively moving vertical plate with ramped wall temperature in a porous medium, in the presence of thermal diffusion, is studied. The exact solution of momentum and energy equations, under the Boussinesq approximation, is obtained in closed form by the Laplace transform technique. The expressions for the skin friction and Nusselt number are also derived. The variations in fluid velocity and temperature are shown graphically whereas numerical values of skin friction and the Nusselt number are presented in tabular form for various values of pertinent flow parameters. The natural convection flow near a ramped temperature plate is also compared with the flow near an isothermal plate.

7

Effect of magnetic field and heat generation/absorption on free convection along semi-infinite vertical porous plate

Tak S. S., Gehlot R. K., Mathur R.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 1

237-248

EN

Heat and momentum transfer in the case of a steady free convection flow along a semi-infinite vertical porous/non-porous plate in the presence of a uniform transverse magnetic field and uniform heat generation/absorption have been investigated. Non-similar solutions of the governing equations have been obtained by taking series expansions of stream function and temperature function. The resulting set of non-linear coupled ordinary differential equations with the appropriate boundary conditions has been solved numerically, using Newton's shooting technique. Numerical values of functions that correspond to the local wall shear stress and the rate of surface heat transfer are tabulated. The velocity function, temperature function, local skin-friction and local Nusselt number are shown graphically for various values of parameters involved and discussed in detail.

8

Estimation of the Overall Heat - transfer Coefficient Through a Textile Layer

Ziegler S., Kucharska-Kot J.

Fibres & Textiles in Eastern Europe

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2006

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Vol. 14, no. 5 (59)

103--106

EN

The article justifies the use of calculative determination of the heat transfer coefficient k, on the basis of immutable parameters of the textile layer such as thermal conductivity and thickness. A method of elaborating the heat transfer coefficient is described, and examples of calculations are presented for randomly selected samples of clothing woven fabrics. It was proved possible to make a calculative estimation of the influence of changes on the parameters of the textile layer, as well as the conditions of use on the value of the heat transfer coefficient. No estimation of the woven fabrics tested from the point of view of their properties was carried out. A brief description of a device for measuring the thermal conductivity coefficient and the heat transfer coefficient of flat textile products is presented.

PL

W artykule wykazano celowość obliczeniowego określania współczynnika przenikania ciepła k, na podstawie stałych parametrów warstwy odzieży: przewodności cieplnej i grubości warstwy. Przedstawiono metodę obliczania współczynnika k i wykonano obliczenia dla wybranych próbek tkanin odzieżowych. Przedstawiono opis przyrządu do pomiaru współczynnika przewodności cieplnej i współczynnika przenikania ciepła płaskich wyrobów włókienniczych. Wyniki pomiarów porównawczych wykazały dostateczną zgodność obliczeń z pomiarami. Wykazano możliwość obliczeniowej oceny wpływu zmian parametrów warstwy odzieży i warunków użytkowania na wartość współczynnika przenikania ciepła.