Reducing the equations of nonlinear non-steady-state high-intensity heat- and mass-transfer to equivalent linear equations. An analogy of the theory of high-intensity heat- and mass-transfer

1968 ◽  
Vol 15 (2) ◽  
pp. 689-691 ◽  
Author(s):  
P. M. Kolesnikov
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Heat And Mass Transfer ◽  
High Intensity ◽  
Linear Equations ◽  
Equivalent Linear

Analysis of Mixed Convective Heat and Mass Transfer on Peristaltic Flow of Fene-P Fluid with Chemical Reaction

2015 ◽  
Vol 32 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Z. Asghar ◽  
N. Ali
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Wave Length ◽  
Linear Equations ◽  
Pressure Rise ◽  
Boussinesq Approximation ◽  
Flow Equations ◽  
Highly Nonlinear ◽  
Concentration Changes

AbstractThis study presents the influence of heat and mass transfer on peristaltic transport of Finitely Extensible Nonlinear Elastic Peterlin (FENE-P) fluid in the presence of chemical reaction. It is assumed that all the fluid properties, except the density are constant. The Boussinesq approximation which relates density change to temperature and concentration changes is used in formulating buoyancy force terms in the momentum equation. Moreover, we neglect viscous dissipation and include diffusion-thermal (Dufour) and thermal-diffusion (Soret) effects in the present analysis. By the consideration of such important aspects the flow equations become highly nonlinear and coupled. In order to make the problem tractable we have adopted widely used assumptions of long wave length and low Reynolds number. An exact solution of the simplified coupled linear equations for the temperature and concentration has been obtained whereas numerical solution is obtained for dimensionless stream function and pressure gradient. The effects of different parameters on velocity field, temperature and concentration fields and trapping phenomenon are highlighted through various graphs. Numerical integration has been performed to analyze pressure rise per wavelength.

Steady-State Performance of a Small-Scale Liquid-to-Air Membrane Energy Exchanger for Different Heat and Mass Transfer Directions, and Liquid Desiccant Types and Concentrations: Experimental and Numerical Data

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Davood Ghadiri Moghaddam ◽  
Philip LePoudre ◽  
Robert W. Besant ◽  
Carey J. Simonson
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Steady State ◽  
Heat And Mass Transfer ◽  
Salt Solution ◽  
Test Facility ◽  
Small Scale ◽  
Air Cooling ◽  
Test Cases ◽  
Membrane Energy

A liquid-to-air membrane energy exchanger (LAMEE) is an energy exchanger that allows heat and moisture transfer between air and salt solution flows through a semipermeable membrane. For the first time, a novel small-scale single-panel LAMEE test facility is used to experimentally investigate the effect of the direction of heat and mass transfers for the air and salt solution flows, and the effect of different salt solution types and concentrations on the LAMEE effectiveness. The data for steady-state effectiveness of the LAMEE are compared to the simulation results of a numerical model. Two studies are conducted; first a study based on different heat and mass transfer directions (four test cases), and second a study focused on the influence of solution types and concentration on LAMEE performance. For the first study, NTU = 3 and four different heat capacity ratios (i.e., Cr* = 1, 3, 5, 7) are used, with a LiCl salt solution in the exchanger. Mass and energy balances for all the test cases and the repeatability of the experimental data for the air cooling and dehumidifying test case show that the experimental data are repeatable and within an acceptable uncertainty range. The results show increasing effectiveness with increasing Cr*, and good agreement between the numerical and experimental results for both air cooling and dehumidifying and air heating and humidifying test cases. In the second study, two different salt solutions (i.e., LiCl and MgCl2), and three different concentrations for the LiCl solution (i.e., 25%, 30%, and 35%) are selected to investigate the effect of different salt solution types and concentrations on the performance of the LAMEE. A maximum difference of 10% is obtained for the LAMEE total effectiveness data with the different salt solution types and concentrations. The results show that both the salt solution type and concentration affect the LAMEE effectiveness, and changing the concentration is one way to control the supply air outlet humidity ratio.

Changed Heat and Mass Transfer Evaluation of a Gas-to-Gas Type Membrane Humidifier by Mass Collection

2010 ◽  
Author(s):  
ByungJun Kim ◽  
SangSeok Yu ◽  
YoungDuk Lee ◽  
KookYoung Ahn
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Steady State ◽  
Heat And Mass Transfer ◽  
Humidity Sensor ◽  
Transient State ◽  
Air Flow Rate ◽  
Dry Air ◽  
Mass And Heat Transfer ◽  
Mass Collection

In this paper, a technique of the humidity measurement is developed to identify the performance of membrane humidifier. The technique is designed to measure the performance of membrane humidifier during steady state and transient state. In particular, the measurement technique is very useful to understand dynamic behavior of humidifier because the response of commercial humidity sensor is too slow to capture the transient response of mass and heat transfer through the membrane. Accordingly, the heat and mass transfer characteristics of membrane humidifier are figured out with the experimental analysis. The parameters used in experiment are dry air pressure, humid air temperature and dry air flow rate.

Non-Conventional Transport Phenomena

1994 ◽  
Author(s):  
Antony N. Beris ◽  
Brian J. Edwards
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Heat And Mass Transfer ◽  
Chemical Potential ◽  
Constitutive Relations ◽  
Diffusion Flux ◽  
Transport Phenomena ◽  
Mass Diffusion ◽  
Constitutive Relationship ◽  
Transient Phenomena

In this chapter, we wish to exploit the availability of the bracket formalism in the description of complex, non-conventional transport phenomena. In the first section, §10.1, we analyze relaxational phenomena in heat and mass transfer. The next section, §10.2, includes the description of phase transitions in inhomogeneous media. The last section, §10.3, contains a first effort to describe inertial effects in viscoelasticity. These problems have rarely been considered in the past, and when they have it has always been from a phenomenological perspective. We explore the availability of the bracket formalism here to provide a more systematic basis for these systems than has heretofore been available, and hence we characterize the models in this chapter as semi-phenomenological. The basic approach that we use is to first establish an appropriate internal variable for the system in consideration, and then to divine an appropriate Hamil-tonian which does, in some limits, produce available phenomenological models. (The latter step indicates why we characterize the models deve-loped in this chapter as “semi-phenomenological.”) As we shall see, describing the models on this more fundamental basis clears up a number of inconsistencies, as well as extending their range of validity without unduly sacrificing their simplicity. In most engineering applications of heat and mass transfer, the simple linear constitutive relations of (6.4-12) are adequate in order to describe the respective transport processes. A couple of very simple examples are the heat flux, when the affinity is the temperature gradient (giving Fourier's law of heat conduction), and the mass diffusion flux, when the affinity is the chemical potential (giving Pick's law of mass diffusion). The importance of such relationships in engineering practice cannot be overestimated. The validity of the linearized equations is generally established by steady-state experiments, so the question that naturally arises is whether or not the same constitutive relationship will hold for transient phenomena. This question cannot be answered as long as only steady-state experiments are performed. From physical considerations alone, it is obvious that the linearized constitutive relationships cannot be complete, in and of themselves.

Electromagnetic and non-Darcian effects on a micropolar non-Newtonian fluid boundary-layer flow with heat and mass transfer

2021 ◽  
pp. 1-11
Author(s):  
Mahmoud E. Ouaf ◽  
Mohamed Y. Abou-zeid
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Numerical Solutions ◽  
Linear Equations ◽  
Physical Parameters ◽  
Electric Parameter ◽  
Similarity Transformations ◽  
Fluid Boundary ◽  
Layer Flow ◽  
Non Linear Equations

The purpose of this paper is to investogate the ectromagnetic and micropolar properties on biviscosity fluid flow with heat and mass transfer through a non-Darcy porous medium. Morever, The heat source, viscous dissipation, thermal diffusion and chemical reaction are taken into consideration. The system of non linear equations which govern the motion is transformed into ordinary differential equations by using a suitable similarity transformations. These equations are solved by making use of Rung–Kutta–Merson method in a shooting and matching technique. The numerical solutions of the velocity, microtation velocity, temperature and concentration are obtained as a functions of the physical parameters of the problem. Moreover the effects of these parameters on these solutions are discussed numerically and depicted graphically. It is found that the microtation velocity increases or deceases as the electric parameter, Hartman parameter and the microrotation parameter increase. Morever, the temperature increases as Forschheimer number, Eckert number increase.

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