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Wyszukujesz frazę "heat generation" wg kryterium: Temat


Tytuł:
A numerical examination of an unsteady nonlinear MHD flow in the presence of thermal radiation and heat generation
Autorzy:
Agbaje, T. M.
Leach, P. G. L.
Powiązania:
https://bibliotekanauki.pl/articles/1839890.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ MHD
promieniowanie cieplne
wytwarzanie ciepła
unsteady MHD flow
spectral perturbation method
spectral relaxation method
thermal radiation
heat generation
Opis:
In this study, the spectral perturbation method and the spectral relaxation method are used to solve the nonlinear differential equations of an unsteady nonlinear MHD flow in the presence of thermal radiation and heat generation. The SPM is mainly based on series expansion, generating series approximation coupled with the Chebyshev spectral method. The numerical results generated using the spectral perturbation method were compared with those found in the literature, and the two results were in good agreement.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 1; 1-17
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of the local entropy generation rate in a porous media burner
Autorzy:
Mohammadi, I.
Esfahani, J. A.
Kim, K. C.
Powiązania:
https://bibliotekanauki.pl/articles/38597672.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
porous media burner
chemical kinetics
volumetric heat transfer
axisymmetric combustion
local entropy generation
excess air ratio
Opis:
In this paper, the work and performance of the premixed methane-air porous axisymmetrical burner have firstly been simulated numerically using the CFD tools. For this purpose the set of governing equations has been enriched by an additional energy equation in porous solid, and the chemical species transport has been extended onto the multi-step mechanism (GRI-2-11). This numerical model has been verified on the base of available benchmark experiments. Next, we have studied the local entropy generation problem taking into account not only classical contributions like viscous and turbulent dissipation but also, the porous combustion of gases. The results showed that the greatest portion of entropy generation in the porous medium burner is related to chemical reactions, followed by heat transfer, mass diffusion (mixing) and friction (viscous dissipation), respectively. According to the results, as the excess air ratio increases, the local entropy generation rate due to heat transfer and friction increases and the local entropy generation rate due to chemical reactions is decreased. Also, by increasing the volumetric heat transfer coefficient, the local entropy generation rate due to heat transfer decreases and the local entropy generation rate due to friction and chemical reactions increases. Also, the local entropy generation rate due to mixing does not show a significant change with the changing excess air ratio and volumetric heat transfer coefficient.
Źródło:
Archives of Mechanics; 2020, 72, 3; 257-279
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An innovative method for waste heat recovery from flue gas treatment system through an additional economizer
Autorzy:
Iliev, Iliya Krastev
Kowalczyk, Tomasz
Beloev, Hristo Kvanov
Terziev, Angel Kostadinov
Jesionek, Krzysztof Jan
Badur, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/2091368.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
waste heat recovery
flue gases
feasibility study
battery emulsifier second generation
bag filters
Opis:
The usage of wet methods for flue gas dedusting from coalfired boilers is associated with significant heat losses and water resources. Widespread emulsifiers of the first and second generation are satisfactory in terms of flue gas cleaning efficiency (up to 99.5%), but at the same time do not create conditions for deeper waste heat recovery, leading to lowering the temperature of gases. Therefore, in the paper, an innovative modernization, including installing an additional economizer in front of the scrubber (emulsifier) is proposed, as part of the flue gas passes through a parallel bag filter. At the outlet of the emulsifier and the bag filter, the gases are mixed in a suitable ratio, whereby the gas mixture entering the stack does not create conditions for condensation processes in the stack.
Źródło:
Archives of Thermodynamics; 2022, 43, 2; 37--59
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the use of waste heat from a glass melting furnace for electricity production in the organic Rankine cycle system
Autorzy:
Musiał, Arkadiusz Mateusz
Antczak, Łukasz
Jędrzejewski, Łukasz
Klonowicz, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1845495.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy efficiency
distributed generation
organic rankine cycle
ORC
industrial waste heat
Opis:
In most production plants, waste heat is usually discharged into the environment, contributing to a reduction in the energy efficiency of industrial processes. This is often due to the low thermal parameters of the carriers in which this energy is contained, such as oils, water, exhaust gases or other post-process gases, which means that their use for electricity production in a conventional Rankine cycle may prove to be economically unprofitable. One of the technologies enabling the use of lowand medium-temperature waste heat carriers is the organic Rankine cycle (ORC) technology. The paper present results of calculations performed to evaluate potential electricity production in ORC using waste heat from a natural gas-fired glass melting furnace. The analysis was carried out assuming the use of a single-stage axial turbine, whose efficiency was estimated using correlations available in the literature. The calculations were carried out for three working fluids, namely hexamethyldisiloxane, dimethyl carbonate, and toluene for two scenarios, i.e. ORC system dedicated only to electricity production and ORC system working in cogeneration mode, where heat is obtain from cooling the condenser. In each of the considered cases, the ORC system achieves the net power output exceeding 300 kW (309 kW for megawatts in the cogenerative mode to 367 kW for toluene in the non-cogenerative mode), with an estimated turbine efficiency above 80%, in range of 80,75 to 83,78%. The efficiency of the ORC system, depending on the used working fluid and the adopted scenario, is in the range from 14.85 to 16.68%, achieving higher efficiency for the non-cogenerative work scenario.
Źródło:
Archives of Thermodynamics; 2021, 42, 1; 15-33
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined systems of energy generation – a characterisation and classification
Autorzy:
Gilewski, J
Montusiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/102889.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
combined heat and power (CHP)
combined energy generation
cogeneration systems
Opis:
The study presents issues concerning technical solutions of combined systems of energy generation which can be used primarily in low-level power plants, installed in various types of public utility sites. A detailed description is given of selected ways of powering combined energy generation systems, presenting conceptual outlines of their operation and information on their advantages, disadvantages and applications. The following systems are introduced: gas-steam, back-pressure steam turbine, extraction-condensing steam turbine, gas turbine, gas microturbine, Stirling engine, fuel cells and internal combustion piston engine. Moreover, the study addresses economic aspects of energy generation in combined systems, discussing different methodologies of cost calculation, including the one used by the European Union. The article also gives a detailed review of piston engine combined-system aggregates available in the Polish market. Type series of associated systems designed for low-power appliances are shown, produced by Polish and foreign companies such as Viessmann, Centrum Elektroniki Stosowanej CES, H. Cegielski – Poznań, KWE Technika Energetyczna, TEDOM Poland or the EPS System.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 23; 53-61
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational and experimental model of electroporation for human aorta
Autorzy:
Filipovic, N.
Saveljic, I.
Jovicic, N.
Tanaskovic, I.
Zdravkovic, N.
Powiązania:
https://bibliotekanauki.pl/articles/306780.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
elektroporacja
wytwarzanie ciepła
ablacja
kształtka wodociągowa
przewodnictwo cieplne
electroporation
heat generation
ablation
VSMC reduction
fitting
conductivity
Opis:
Purpose: In this study the computational and experimental electroporation model with human aorta tissue is made in order to examine the reduction of smooth muscle cells. Methods. The segments in native state of the aorta are treated by electroporation method through a series of electrical impulses from 50 V/cm to 2500 V/cm. For each patient we analyzed one sample with and one sample without electroporation as a control. In the computational study, electrical field distribution is solved by the Laplace equation. The Pennes Bioheat equation without metabolism and blood perfusion heating is used to solve heat transfer problems. Different conductivity values are used in order to fit the experimental results. Results: Experimental histology has shown us that there are a smaller number of vascular smooth muscle cells (VSMC) nuclei at the tunica media, while the elastic fibre morphology is maintained 24 h after electroporation. In the computational model, heat generation coupled with electrical field is included. The fitting procedure is applied for conductivity values in order to make material properties of the aorta tissue. The fitting procedure gives tissue conductivity of 0.44 [S/m] for applied electrical field of 2500 V/cm. Conclusions: Future studies are necessary for investigation of a new device for in-vivo ablation with electroporation of plaque stenosis. It will open up a new avenue for stenosis treatment without stent implantation.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 4; 15-20
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Internal Heat Generation on the Thermal Stability of a Porous Fin
Autorzy:
Sobamowo, M. G.
Jayesimi, L. O.
Waheed, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/1031875.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Differential Transformation Method
Porous Fin
Temperature-Dependent Internal Heat Generation
Thermal analysis
Thermal performance
Opis:
In this study, the effects of internal heat generation on thermal stability of porous fin is theoretical investigated using differential transform method. The parametric studies reveal increase in the internal heat generation leads to increase in the value or the range of the thermal stability of the fin. The internal heat generation can be used to control the thermal instability in the fin. Also, as the porosity parameter increase, the rate of heat transfer from the base of the fin and consequently improve the efficiency of the fin increase. However, a high value or an excessive internal heat generation results in an undesirable situation where some of the heat energy cannot escape to the sink and instead ends up flowing into the prime surface and the fin tends to store heat rather than dissipating it. This scenario defeats the prime purpose of the cooling fin. Therefore, the operational parameters must be carefully selected to ensure that the fin retains its primary purpose of removing heat from the primary surface.
Źródło:
World Scientific News; 2020, 149; 110-127
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of non-uniform heat generation /absorption and radiation on hydromagnetic dissipative flow over a porous nonlinear stretching surface with heat and mass fluxes
Autorzy:
Anjali Devi, S. P.
Agneeshwari, M.
Powiązania:
https://bibliotekanauki.pl/articles/264962.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
magnetohydrodynamika
strumień ciepła
strumień masy
absorpcja ciepła
MHD
heat flux
mass flux
non-uniform heat generation/absorption
Opis:
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.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 36-52
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of thermal radiation and heat generation on hydromagnetic flow of nanofluid over an exponentially stretching sheet in a porous medium with viscous dissipation
Autorzy:
Murugesan, Thiagarajan
Kumar, M. Dinesh
Powiązania:
https://bibliotekanauki.pl/articles/1059429.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
MHD
Nanofluid
exponentially stretching sheet
heat generation
porous medium
thermal radiation
viscous dissipation
Opis:
This paper studies, the impacts of heat generation on MHD flow of radiative nanofluid over an exponentially stretching sheet in a porous medium with viscous dissipation are numerically analyzed. Two sorts of nanofluids, generated by solid nanoparticles with water such as alumina-water nanofluid and silver-water nanofluid were investigated. With the use of similarity transformations, to obtain a system of nonlinear ordinary differential equations. The resulting boundary value problem is solved numerically using the Nachtsheim-Swigert shooting technique scheme together with fourth-order Runge-Kutta integration method. Numerical results are obtained for the velocity, temperature distribution and concentration profiles for selected values of the governing physical parameters of combined magnetic interaction and porosity parameter, heat generation parameter, viscous dissipation parameter, thermal radiation parameter, solid volume fraction parameter, chemical reaction parameter and Lewis number are discussed. Quantities of engineering interest such as Skin friction coefficient, Nusselt number, and Sherwood number are also obtained numerically and are tabulated.
Źródło:
World Scientific News; 2019, 128, 2; 130-147
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of variable viscosity on natural convection flow of an optically thick gray gas past a horizontal surface in the presence of internal heat generation
Autorzy:
Kannan, T.
Malleswaran, A.
Moorthy, M. B. K.
Powiązania:
https://bibliotekanauki.pl/articles/175425.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
assisting and opposing flows
Dufour and Soret effects
internal heat generation
natural convection
radiation
variable viscosity
Opis:
A numerical investigation to discuss the effects of radiation and variable viscosity on heat and mass transfer characteristics of natural convection over a horizontal surface embedded in a saturated porous medium in the presence of internal heat generation is carried out in this study. The working fluid for the investigation is optically thick gray gas. The Dufour and Soret effects are also taken into account. Similarity transformations are employed to obtain nonlinear ordinary differential equations from the governing equations of the present problem. The numerical results for the transformed governing equations are computed by using commercial boundary value problem solver for ordinary differential equations. The effects are discussed by varying the parameters such as radiation, Dufour and Soret numbers, buoyancy ratio, Prandtl number, Schmidt number, and variable viscosity. Presence of internal heat generation enhances the velocity profile and significantly decreases the concentration boundary layer thickness. On increasing fluid radiation, the temperature of the fluid is higher than that of the surface and the concentration boundary layer thickness decreases away from the surface.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2018, 139; 3-22
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Emission and trends in reclaiming waste heat in industrial instalations
Autorzy:
Hys, L.
Wiak, T
Powiązania:
https://bibliotekanauki.pl/articles/952453.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
heat emission
waste heat
heat waste reclaim
distributed generation
Opis:
The article presents the analysis of waste heat emission in a typical industrial installation. On the basis of the process monitoring system, periodic analyses of fumes composition, installation process manual and the conducted measurements of the heat fluxes from individual sources emitting heat on the way of natural convection from the devices’ coats and forced convection in the fumes flux were calculated. According to the authors the heat of temperature 140–155 °C and surface power density 860–970 W/m2 emitted by devices’ covers can be reclaimed in ORC techniques, Peltier’s modules and the systems realising Stirling cycle. Part of the waste heat included in fumes, which makes c.a. 76% of the total emission from the installation, should be returned to the process of fuel oxidation, what will reduce the emission by c.a. 18% and the volume of consumed fuel by c.a. 25 m3 CH4/h, according to the presented calculations.
Źródło:
Journal of Ecological Engineering; 2013, 14, 2; 26-30
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy generation and squeezing flow past a Riga plate with Cattaneo-Christov heat flux
Autorzy:
Atlas, M.
Hussain, S.
Sagheer, M.
Powiązania:
https://bibliotekanauki.pl/articles/202419.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanowłókna
konwekcyjne warunki brzegowe
strumień ciepła Cattaneo-Christova
generowanie entropii
squeezing flow
Riga plate
nanofluids
convective boundary conditions
Cattaneo-Christov heat flux
entropy generation
Opis:
In this article, we investigate the convective heat transfer of the two-dimensional unsteady squeezing flow past a Riga plate. To examine the heat transfer, Cattaneo-Christov heat flux model is used. Influence of entropy generation on heat transfer has been investigated numerically. With the help of suitable similarity transformation, the governing partial differential equations (PDEs) are converted into ordinary differential equations (ODEs). The obtained system of non-linear ordinary differential equations subject to the convective boundary conditions is solved by the shooting method using the computational software MATLAB. To strengthen the reliability of the results obtained by the shooting method, the MATLAB built-in function bvp4c has been used. The graphs show the effect of different physical parameters for velocity, temperature, concentration and tables are presented to observe the behaviour of skin friction and sherwood number under the influence of certain physical parameters. It is observed that for increasing values of thermal relaxation parameter, the temperature profile increases and an opposite behaviour is shown for the concentration profile. Moreover, with an increase in the Brinkman number, the entropy generation increases.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 3; 291-300
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy generation minimization in steady-state and transient diffusional heat conduction processes Part I – Steady-state boundary value problem
Autorzy:
Kolenda, Z. S.
Szmyd, J. S.
Huber, J.
Powiązania:
https://bibliotekanauki.pl/articles/200901.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat conduction
entropy generation
boundary value problems
Euler-Lagrange variational equation
przewodzenia ciepła
generacja entropii
problemy granica -wartość
wariacyjne równanie Eulera-Lagrange'a
Opis:
An application of the Entropy Generation Minimization principle allows new formulation of the boundary and initial boundaryvalue problems. Applying Euler-Lagrange variational formalism new mathematical form of heat conduction equation describing steady-state processes have been derived. Mathematical method presented in the paper can also be used for any diffusion heat and mass transfer process. Linear and non-linear problems with internal heat sources have been analyzed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 4; 875-882
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy generation minimization in transient heat conduction processes PART II – Transient heat conduction in solids
Autorzy:
Kolenda, Z. S.
Szmyd, J. S.
Powiązania:
https://bibliotekanauki.pl/articles/201936.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transient heat conduction
initial boundary value problem
entropy generation minimization
przewodzenia ciepła
początkowa wartość graniczna
minimalizacja entropii generacji
Opis:
Formulation and solution of the initial boundary-value problem of heat conduction in solids have been presented when an entropy generation minimization principle is imposed as the arbitrary constraint. Using an entropy balance equation and the Euler-Lagrange variational approach a new form of the heat conduction equation (non-linear partial difference equation) is derived.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 4; 883-887
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy generation on MHD slip flow over a stretching cylinder with heat generation/absorption
Autorzy:
Jain, S.
Bohra, S.
Powiązania:
https://bibliotekanauki.pl/articles/264521.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
magnetohydrodynamika
wytwarzanie ciepła
poślizg
entropia
magnetohydrodynamic
heat generation
slip
entropy
Opis:
In the present study, we have investigated entropy generation on a magnetohydrodynamic fluid flow and heat transfer over a stretching cylinder with a porous medium in slip flow regime. A uniform heat source and radiation is also considered. Similarity transformation has been applied for making an ordinary differential equation from nonlinear governing partial differential equations. The numerical solution for the set of nonlinear ordinary differential equations has been obtained by using the fourth-order Runge-Kutta scheme together with the shooting method. The effects of pertinent parameters such as the magnetic field parameter, permeability parameter, slip parameter, Prandtl number and radiation parameter on the fluid velocity distribution, temperature distribution, entropy generation and Bejan number are discussed graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 2; 413-428
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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