Book•
Convection Heat Transfer
01 Jan 1984-
TL;DR: In this paper, the authors describe a transition from Laminar boundary layer flow to Turbulent Boundary Layer flow with change of phase Mass Transfer Convection in Porous Media.
Abstract: Fundamental Principles Laminar Boundary Layer Flow Laminar Duct Flow External Natural Convection Internal Natural Convection Transition to Turbulence Turbulent Boundary Layer Flow Turbulent Duct Flow Free Turbulent Flows Convection with Change of Phase Mass Transfer Convection in Porous Media.
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TL;DR: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics as mentioned in this paper.
Abstract: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics. These simple models are used in the optimization of real (irreversible) devices and processes, subject to finite‐size and finite‐time constraints. The review traces the development and adoption of the method in several sectors of mainstream thermal engineering and science: cryogenics, heat transfer, education, storage systems, solar power plants, nuclear and fossil power plants, and refrigerators. Emphasis is placed on the fundamental and technological importance of the optimization method and its results, the pedagogical merits of the method, and the chronological development of the field.
1,516 citations
TL;DR: In this paper, the authors studied the natural convective boundary-layer flow of a nanofluid past a vertical plate and found that the reduced Nusselt number is a decreasing function of each of Nr, Nb and Nt.
1,218 citations
TL;DR: (hierarchical, Lagrange) reduced basis approximation and a posteriori error estimation for linear functional outputs of affinely parametrized elliptic coercive partial differential equations are considered.
Abstract: In this paper we consider (hierarchical, La-grange)reduced basis approximation anda posteriori error estimation for linear functional outputs of affinely parametrized elliptic coercive partial differential equa-tions. The essential ingredients are (primal-dual)Galer-kin projection onto a low-dimensional space associated with a smooth “parametric manifold” - dimension re-duction; efficient and effective greedy sampling meth-ods for identification of optimal and numerically stable approximations - rapid convergence;a posteriori er-ror estimation procedures - rigorous and sharp bounds for the linear-functional outputs of interest; and Offine-Online computational decomposition strategies - min-imummarginal cost for high performance in the real-time/embedded (e.g., parameter-estimation, control)and many-query (e.g., design optimization, multi-model/ scale)contexts. We present illustrative results for heat conduction and convection-diffusion,inviscid flow, and linear elasticity; outputs include transport rates, added mass,and stress intensity factors.
1,090 citations
TL;DR: In this paper, the authors developed a solution to the fundamental problem of how to collect and "channel" to one point the heat generated volumetrically in a low conductivity volume of given size.
771 citations
TL;DR: In this article, the Cheng-Minkowycz problem of natural convection past a vertical plate, in a porous medium saturated by a nanofluid, is studied analytically.
760 citations
References
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Book•
31 Dec 1959
TL;DR: In this paper, a classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems, including boundary value maximization.
Abstract: This classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems.
21,807 citations
TL;DR: In this paper, it was shown analytically that the distribution of concentration produced in this way is centred on a point which moves with the mean speed of flow and is symmetrical about it in spite of the asymmetry of the flow.
Abstract: When a soluble substance is introduced into a fluid flowing slowly through a small-bore tube it spreads out under the combined action of molecular diffusion and the variation of velocity over the cross-section. It is shown analytically that the distribution of concentration produced in this way is centred on a point which moves with the mean speed of flow and is symmetrical about it in spite of the asymmetry of the flow. The dispersion along the tube is governed by a virtual coefficient of diffusivity which can be calculated from observed distributions of concentration. Since the analysis relates the longitudinal diffusivity to the coefficient of molecular diffusion, observations of concentration along a tube provide a new method for measuring diffusion coefficients. The coefficient so obtained was found, with potassium permanganate, to agree with that measured in other ways. The results may be useful to physiologists who may wish to know how a soluble salt is dispersed in blood streams.
4,530 citations
TL;DR: In this paper, it was shown that the rate of growth of the variance is proportional to the sum of the molecular diffusion coefficient and the Taylor diffusion coefficient, where U is the mean velocity and a is a dimension characteristic of the cross-section of the tube.
Abstract: Sir Geoffrey Taylor has recently discussed the dispersion of a solute under the simultaneous action of molecular diffusion and variation of the velocity of the solvent. A new basis for his analysis is presented here which removes the restrictions imposed on some of the parameters at the expense of describing the distribution of solute in terms of its moments in the direction of flow. It is shown that the rate of growth of the variance is proportional to the sum of the molecular diffusion coefficient, D, and the Taylor diffusion coefficient $\kappa $a$^{2}$U$^{2}$/D, where U is the mean velocity and a is a dimension characteristic of the cross-section of the tube. An expression for $\kappa $ is given in the most general case, and it is shown that a finite distribution of solute tends to become normally distributed.
2,334 citations
TL;DR: In this article, the Fourier series is used to obtain fundamental solutions of the Stokes equations of motion for a viscous fluid past a periodic array of obstacles, and it is shown that the divergence of the lattice sums pointed out by Burgers may be rescued by taking into account the presence of the mean pressure gradient.
Abstract: Spatially periodic fundamental solutions of the Stokes equations of motion for a viscous fluid past a periodic array of obstacles are obtained by use of Fourier series. It is made clear that the divergence of the lattice sums pointed out by Burgers may be rescued by taking into account the presence of the mean pressure gradient. As an application of these solutions the force acting on any one of the small spheres forming a periodic array is considered. Cases for three special types of cubic lattice are investigated in detail. It is found that the ratios of the values of this force to that given by the Stokes formula for an isolated sphere are larger than 1 and do not differ so much among these three types provided that the volume concentration of the spheres is the same and small. The method is also applied to the two-dimensional flow past a square array of circular cylinders, and the drag on one of the cylinders is found to agree with that calculated by the use of elliptic functions.
908 citations
TL;DR: In this paper, the conduction of heat through a stationary random suspension of spheres is studied for a volume fraction of the spheres (c) which is small, and the work of Maxwell (1873) is extended to calculate the flux of heat exactly to order c 2 by using the method of Batchelor (1972), which reduces the problem to a consideration of interactions between pairs of spheres while avoiding the usual convergence difficulties.
Abstract: The conduction of heat (or electricity) through a stationary random suspension of spheres is studied for a volume fraction of the spheres (c) which is small. The work of Maxwell (1873) is extended to calculate the flux of heat exactly to order c 2 by using the method of Batchelor (1972), which reduces the problem to a consideration of interactions between pairs of spheres while avoiding the usual convergence difficulties. The result depends on the way in which pairs of spheres are distributed with respect to each other; for the case of all possible pair configurations being equally probable the coefficient of c 2 is found explicitly for all values of the ratio of conductivities of the two phases. The results also apply to permittivities and permeabilities of suspensions.
680 citations