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Unsteady mixed convection flow over stretching sheet in presence of chemical reaction and heat generation or absorption with non-uniform slot suction or injection

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Applied Mathematics and Mechanics(English Edition) 2015年第10期36卷 1253-1272页

作者： R.RAVINDRAN N.SAMYUKTHA Department of Mathematics National Institute of Technology

The article examines the unsteady mixed convection flow over a vertical stretching sheet in the presence of chemical reaction and heat generation or absorption with non-uniform mass transfer. The unsteadiness is caused by the time dependent free stream velocity varying arbitrarily with time. Non-similar solutions are obtained nu- merically by solving the coupled nonlinear partial differential equations using the quasi- linearization technique in combination with an implicit finite difference scheme. To reveal the tendency of the solutions, typical results for the local skin friction coefficient and the local Nusselt and Sherwood numbers are presented for different values of parameters. The effects of various parameters on the velocity, temperature, and concentration distributions are discussed here. The present numerical results are compared with the previously published work, and the results are found to be in excellent agreement.

关键词： unsteady mixed convection non-similar solution non-uniform slot suction,stretching sheet chemical reaction heat generation

Effects of chemical reaction Caused by Cooling Stream on Film Cooling Effectiveness

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Journal of Thermal Science 2012年第1期21卷 60-65页

作者： Keyong Cheng Shiqiang Liang Xiulan Huai Wei Chen Yongxian Guo Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China School of Mechano-electronic Engineering Xidian University Xi’an 710071 Shaanxi China

With the increase of inlet temperature of gas turbines, the benefits by using the conventional methods are likely to approach their limits. Therefore, it is essential to study novel film cooling methods for surpassing these current limits. Based on the theory of heat transfer enhancement, a film cooling method with chemical reaction by cool- ing stream is proposed. In order to test the feasibility of the proposed method, numerical simulations have been conducted. The classic flat plate structure with a 30 degree hole is used for the simulation. In the present study, the effects of the parameters in relation to the chemical reaction on film cooling effectiveness, such as chemical heat sink, volume changes, and reaction rate, are investigated numerically. The conventional film cooling is also calculated for the comparison. The results show that film cooling effectiveness is improved obviously due to the chemical reaction, and the reaction heat and reaction rate of cooling stream have an important effect on film ef- fectiveness. However, the effect of volume changes can be ignored.

关键词： Gas turbine Film cooling chemical reaction Heat transfer Numerical simulation

Radiation-absorption,chemical reaction,Hall and ion slip impacts on magnetohydrodynamic free convective flow over semi-infinite moving absorbent surface

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Chinese Journal of chemical Engineering 2021年第6期34卷 40-52页

作者： M.Veera Krishna Department of Mathematics Rayalaseema UniversityKurnoolAndhra Pradesh 518007India

The investigation of radiation-absorption,chemical reaction,Hall and ion-slip impacts on unsteady MHD free convective laminar flow of an incompressible viscous,electrically conducting and heat generation/absorbing fluid enclosed with a semi-infinite porous plate within a rotating frame has been *** plate is assumed to be moving with a constant velocity in the direction of fluid movement.A uniform transverse magnetic field is applied at right angles to the porous surface,which is absorbing the fluid with a suction velocity changing with *** non-dimensional governing equations for present investigation are solved analytically making use of two term harmonic and non-harmonic *** graphical results of velocity,temperature and concentration distributions on the analytical solutions are displayed and discussed with reference to pertinent *** is found that the velocity profiles decreased with an increasing in Hartmann number,rotation parameter,the Schmidt number,heat source parameter,while it increased due to an increase in permeability parameter,radiation-absorption parameter,Hall and ion slip ***,the temperature profile is an increasing function of radiation-absorption parameter,whereas an increase in chemical reaction parameter,the Schmidt number Sc or frequency of oscillations decrease the temperature profile on ***,it is found that the concentration profile is decreased with an escalating in the Schmidt number or the chemical reaction parameter.

关键词： chemical reaction Free convection Heat source Heat transfer Mass diffusion Radiation absorption

Simultaneous effects of chemical reaction and Ohmic heating with heat and mass transfer over a stretching surface: A numerical study

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Chinese Journal of chemical Engineering 2017年第9期25卷 1137-1142页

作者： S.R.Mishra M.M.Bhatti Department of Mathematics Siksha ‘O’ Anusandhan University Shanghai Institute of Applied Mathematics and Mechanics Shanghai University

In this article, we have considered the simultaneous influence of ohmic heating and chemical reaction on heat and mass transfer over a stretching sheet. The effects of applied magnetic field are also taken into consideration while the induced magnetic field is not considered due to very small magnetics Reynolds number. The governing flow problem comprises of momentum, continuity, thermal energy and concentration equation which are transformed into highly nonlinear coupled ordinary differential equations by means of similarity transforms, which are then, solved numerically with the help of Successive Linearization method(SLM) and Chebyshev Spectral collocation method. Numerical values of skin friction coefficient, local Nusselt number, and Sherwood number are also taken into account with the help of tables. The physical influence of the involved parameters of flow velocity, temperature and concentration distribution is discussed and demonstrated graphically. The numerical comparison is also presented with the existing published results and found that the present results are in excellent agreement which also confirms the validity of the present methodology.

关键词： Ohmic heating Heat and mass transfer chemical reaction Successive linearization method

Study on the key problems of interaction between microwave and chemical reaction

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Frontiers of Electrical and Electronic Engineering in China 2007年第4期2卷 473-480页

作者： YANG Xiaoqing HUANG Kama College of Electronics and Information Engineering Sichuan UniversityChengdu 610064China

Microwave has been found as an efficient heating method in chemical ***,in present days the interaction between microwave and chemical reactions has not been deeply understood,which restricts a wider application of high power microwave in chemical *** this paper,the key problems of interaction between microwave and chemical reaction are investigated,such as complex effective permittivity of chemical reaction,simulation of microwave heating on chemical reaction and non-thermal effect of microwave,which will enhance further knowledge of the mechanism of interaction between microwave and chemical ***,such an analysis is beneficial for handling with difficulties in application of microwave chemical industry.

关键词： microwave chemical reaction interaction complex effective permittivity numerical simulation non-thermal effect

Preparation of Nb_(3)Al powder by chemical reaction in molten salts

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Rare Metals 2022年第5期41卷 1671-1676页

作者： Na Wang Cai-Yun Huang Yao Zhang Hong-Min Zhu School of Materials Science and Engineering Beijing University of TechnologyBeijing 100024China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Tangshan Iron and Steel International Engineering Technology Co. LtdTangshan 063000China

Nb_(3)Al nanoparticles were directly synthesized by metallothermic reduction process in the molten salts with mNbCl_(5)-nAlCl_(3) powders as raw materials and sodium as reducing reagent. The effects of different feeding material orders, soaking time, Nb content in raw materials, and 3NbCl_(5)-AlCl_(3) content in molten salts on the obtained Nb_(3)Al powder were discussed. The as-prepared samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). It is found that the only phase Nb_(3)Al nanoparticles are obtained by controlling the variation of the feeding material orders, soaking time, and Nb content in raw materials. And the morphologies of as-prepared nanoparticles change owning to different 3NbCl_(5)-AlCl_(3) contents in molten salts.

关键词： chemical reaction Nb3Al nanoparticles Feeding material orders Molten salt

Viscous and Ohmic heating effects in doubly stratified free convective flow over vertical plate with radiation and chemical reaction

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 139-152页

作者： P.GANESAN R.K.SUGANTHI P.LOGANATHAN Department of Mathematics Anna University Chennai

An analysis is carried out to study the combined effects of viscous and Ohmic heating in the transient, free convective flow of a viscous, incompressible, and doubly stratified fluid past an isothermal vertical plate with radiation and chemical reactions. The governing boundary layer equations are solved numerically by an implicit finite difference scheme of the Crank-Nicolson type. The influence of different parameters on the velocity, the temperature, the concentration, the skin friction, the Nusselt number, and the Sherwood number is discussed with graphical illustrations. It is observed that an increase in either the thermal stratification or the mass stratification parameter decreases the velocity. An increase in the thermal stratification increases the concentration and decreases the temperature while an opposite effect is observed for an increase in the mass stratification. An augmentation in viscous and Ohmic heating increases the velocity and temperature while decreases the concentration. The results are found to be in good agreement with the existing solutions in literature.

关键词： thermal stratification mass stratification Ohmic dissipation viscousdissipation chemical reaction radiation

Advanced Study of Unsteady Heat and chemical reaction with Ramped Wall and Slip Effect on a Viscous Fluid

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Communications in Theoretical Physics 2017年第3期67卷 301-308页

作者： Ayesha Sohail K.Maqbool Noreen Sher Akbar Muhammad Younas Department of Mathematics COMSATS Institute of Information technology Lahore Pakistan Department of Mathematics & Statistics FBAS IIU Islamabad 44000 Pakistan DBS&H CEME National University of Sciences and DBS&H CEME National University of Sciences and Technology Islamabad Pakistan

This paper investigate the effect of slip boundary condition, thermal radiation, heat source, Dufour number,chemical reaction and viscous dissipation on heat and mass transfer of unsteady free convective MHD flow of a viscous fluid past through a vertical plate embedded in a porous media. Numerical results are obtained for solving the nonlinear governing momentum, energy and concentration equations with slip boundary condition, ramped wall temperature and ramped wall concentration on the surface of the vertical plate. The influence of emerging parameters on velocity,temperature and concentration fields are shown graphically.

关键词： free convection thermal radiation MHD viscous dissipation chemical reaction heat source Dufour number porous media

Influence of chemical reaction on heat and mass transfer of non-Newtonian fluid with yield stress by free convection from vertical surface in porous medium considering Soret effect

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Applied Mathematics and Mechanics(English Edition) 2010年第6期31卷 675-684页

作者： F. S. IBRAHIM F. M. HADY S. M. ABDEL-GAIED M. R. EID Department of Mathematics Faculty of Science Assiut University Department of Science and Mathematics Faculty of Education Assiut University

The effect of chemical reaction on free convection heat and mass transfer for a non-Newtonian power law fluid over a vertical flat plate embedded in a fluid-saturated porous medium has been studied in the presence of the yield stress and the Soret effect. The governing boundary layer equations and boundary conditions are cast into a dimen- sionless form by similarity transformations, and the resulting system of equations is solved by a finite difference method. The results are preSented and discussed for concentration profiles, as well as the Nusselt number and the Sherwood number for various values of the parameters, which govern the problem. The results obtained show that the flow field is influenced appreciably by the presence of the chemical reaction parameter γ the order *** chemical reaction parameter m, the Soret number St, the buoyancy ratio N, the Lewis number Le, and the dimensionless rheological parameter Ω.

关键词： non-Newtonian fluid free convection chemical reaction yield stress Soret effect