Download or read book Modeling and Numerical Simulation of Flow and Heat Phenomena in a Telecommunication Heat Cabinet written by Raluca Moglan and published by . This book was released on 2013 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we present a new 3D approach for solving the incompressible Navier-Stokes equations under the Boussinesq approximation. The advantage of the developed numerical code is the use of high order methods for time integration (3rd order Runge-Kutta method) and spatial discretization (6th order finite difference schemes). A study of the order of the numerical method was made, followed by an extensive validation for several cases of natural convection. A finite element simulation code for the same problem was developed using FreeFem++, and was validated with respect to the same cases of natural convection. The case of a telecommunication cabinet was treated by modelling interior obstacles generating heat using an immersed boundary method. This method was validated with respect to the finite element simulation, and many other cases from the literature. We present the results for different 2D and 3D configurations, with obstacles differently placed inside the cavity. Results are also presented for the comparison with experimental measurements in a cabinet with two components dissipating heat. The finite element code is finally extended and tested to simulate phase change materials that could serve as passive cooling devices.

Download or read book Modelling and Numerical Simulation of Fluid Flow and Heat Transfer in Thermoplates written by Boban Maletić and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Simulation of Turbulent Heat Transfer written by B. Sundén and published by WIT Press. This book was released on 2005-02-21 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing invaluable information for both graduate researchers and R & D engineers in industry and consultancy, this book focuses on the modelling and simulation of fluid flow and thermal transport phenomena in turbulent convective flows. Its overall objective is to present state-of-the-art knowledge in order to predict turbulent heat transfer processes in fundamental and idealized flows as well as in engineering applications. The chapters, which are invited contributions from some of the most prominent scientists in this field, cover a wide range of topics and follow a unified outline and presentation to aid accessibility.

Download or read book Two Phase Flow Phase Change and Numerical Modeling written by Amimul Ahsan and published by IntechOpen. This book was released on 2011-09-26 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.

Download or read book Modern Developments in Numerical Simulation of Flow and Heat Transfer written by James L. S. Chen and published by . This book was released on 1992 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulations of Heat Transfer and Fluid Flow on a Personal Computer written by Susumu Kotake and published by Elsevier Publishing Company. This book was released on 1993 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes methodologies for performing numerical simulations of transport processes in heat transfer and fluid flow. The reader is guided to make the proper selection of simulation techniques and to interpret the acquired results based on the flow physics involved. Computer programs which are used to solve heat transfer and fluid flow problems are integrated into the text. Illustrative examples of thermo-fluid phenomena are provided in every chapter to enhance understanding of the subjects by offering the reader hands-on experience of numerical simulations. Most of the fundamental transport processes in heat transfer and fluid flow, e.g. heat conduction in a solid body, convection heat transfer of a fin, laminar and turbulent heat transfer and flow in a duct or tube, and boundary layers over a flat plate are covered. A strong emphasis is placed on examinations of the thermo-fluid phenomena inside a flow passage (such as tube and a channel). The book contains detailed discussions on the formulation of the boundary conditions which is often the key issue in making successful numerical simulations of the physical phenomena of interest. Simulations are carefully designed so that conventional 16-bit personal computers, such as IBM PCreg; or Apple Macintoshreg; can be used. Visualizing the simulated results in graphic form (plotting charts and line contours of physical variables) significantly enhances the reader's understanding of the important transport processes. The book is intended as an introductory text for numerical simulations of heat transfer and fluid flow phenomena. Description is simple and self-contained so that beginners can easily understand the material, yet it will also serve as a useful reference work for the practitioner. Exercise problems are supplied by which the reader can consolidate knowledge of simulation techniques described and gain further insight in the physical processes of interest. The book contains two 3frac12; inch floppy disks, each of which stores a complete set of simulation source codes discussed in the text. These programs are recorded in ASCII format and can be run either on IBM PCreg; or Macintoshreg; using QuickBasicreg;. The programs are well-documented within the text as well as in the codes themselves with a number of comment statements. This helps the reader understand the flow of program runs and, if the reader so wishes, modifying the original source codes. To facilitate prescription of the physical conditions for simulations, these programs run in a highly interactive mode. In addition, the diskettes contain a number of compiled programs which can be executed without the QuickBasicreg; program.

Download or read book Three dimensional Numerical Simulation of Fluid Flow and Heat Transfer in Fin and tube Heat Exchangers at Different Flow Regimes written by Leslye Paniagua Sánchez and published by . This book was released on 2014 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims at unifying two distinct branches of work within the Heat Transfer Technological Center (CTTC). On one side, extensive experimental work has been done during the past years by the researchers of the laboratory. This experimental work has been complemented with numerical models for the calculation of fin and tube heat exchangers thermal and fluid dynamic behavior. Such numerical models can be referred to as fast numerical tool which can be used for industrial rating and design purposes. On the other hand, the scientists working at the research center have successfully developed a general purpose multi-physics Computational Fluid Dynamics (CFD) code (TermoFluids). This high performance CFD solver has been extensively used by the co-workers of the group mainly to predict complex flows of great academic interest. The idea of bringing together this two branches, comes from the necessity of a reliable numerical platform with detailed local data of the flow and heat transfer on diverse heat exchanger applications. Being able to use local heat transfer coefficients as an input on the rating and design tool will lead to affordable and accurate prediction of industrial devices performance, by which the center can propose enhanced alternatives to its industrial partners. To accomplish these goals, several contributions have been made to the existing TermoFluids software which is in continuous evolution in order to meet the competitive requirements. The most significant problematics to adequately attack this problem are analyzed and quite interesting recommendations are given. Some of the challenging arising issues involve the generation of suitable and affordable meshes, the implementation and validation of three dimensional periodic boundary condition and coupling of different domains with important adjustments for the study of cases with different flow physics like time steps and thermal development. Turbulence is present in most of engineering flows, and refrigeration evaporator heat exchangers are not an exception. The presence of many tubes (acting like bluff bodies for the flow) arranged in different configurations and the fact that the flow is also confined by fins, create complex three dimensional flow features that have usually turbulent or transition to turbulent regime. Therefore, three dimensional turbulent forced convection in a matrix of wall-bounded pins is analyzed. Large Eddy Simulations (LES) are performed in order to assess the performance of three different subgrid-scale models, namely WALE, QR and VMS. The Reynolds numbers of the study were set to 3000, 10000 and 30000. Some of the main results included are the pressure coefficient around the cylinders, the averaged Nusselt number at the endwalls and vorticity of the flow. The final part of the thesis is devoted to study the three dimensional fluid flow and conjugated heat transfer parameters encountered in a plate fin and tube heat exchanger used for no-frost refrigeration. The numerical code and post processing tools are validated with a very similar but smaller case of a heat exchanger with two rows of tubes at low Reynolds for which experimental data is available. The next analysis presented is a typical configuration for no-frost evaporators with double fin spacing (for which very few numerical data is reported in the scientific literature). Conjugated convective heat transfer in the flow field and heat conduction in the fins are coupled and considered. The influence of some geometrical and flow regime parameters is analyzed for design purposes. In conclusion, the implementations and general contributions of the present thesis together with the previous existent multi-physics computational code, has proved to be capable to perform successful top edge three dimensional simulations of the flow features and heat transfer mechanisms observed on heat exchanger devices.

Download or read book Numerical Simulations of Laminar Transitional and Turbulent Flow and Heat Transfer in Continuous and Interrupted plate Channels written by Kelechi Ezeji and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The long-term goal of this research is to contribute to the development of mathematical models and numerical solution methods for use as cost-effective tools in procedures for designing the next generation of compact and ultra-compact heat exchangers (core heat transfer area density exceeding 700 m^2/m^3 and 3000 m^2/m^3, respectively). Such heat exchangers are expected to play a major role in ongoing worldwide efforts to propose novel energy conversion systems. The desire to participate in such efforts is the main motivation for this work. Attention in this work was focused on rectangular offset strip-fin plate-fin core configurations. Over the last 50 years, there have been many efforts to increase the compactness of such cores. However, increasing compactness reduces the hydraulic diameter and (hence) the Reynolds number, for the same average velocity, which can lead to turbulent-to-laminar transition. These consequences of increasing compactness bring up the issue of its effect on the rate of heat transfer for a fixed pumping power. The rectangular offset strip-fin plate-fin configuration causes starting, interrupting, and restarting of both velocity and thermal boundary layers, and also possible unsteadiness and vortex shedding; and these thermofluid features bring up the issue of maximizing heat transfer for specified heat transfer surface area and fixed pumping power.The main goal of this research was to contribute to the resolution of the first of the aforementioned two issues, in a highly cost-effective manner. Thus, fins of negligible thickness and flow passages of large cross-sectional aspect ratio were assumed, and attention was limited to steady two-dimensional fluid flow and heat transfer phenomena. Air was the fluid of choice, and it was assumed that its thermophysical properties remained essentially constant. Furthermore, the Eckert number was much less than one in the problems considered here, so viscous dissipation could be ignored.Elliptic and parabolic mathematical models of developing fluid flow and heat transfer in continuous parallel-plate channels and arrays of regular staggered plates were considered. Three different low-Reynolds-number turbulence models (all capable of predicting turbulent-laminar transition with reduction in Reynolds number) were selected for comparative assessment. These mathematical models were solved using two-dimensional elliptic (2DE) and parabolic (2DP) finite volume methods (FVMs): the 2DE FVM was an adapted version of an in-house code; the 2DP FVM was specially formulated and implemented for this work, retaining the momentum equation in the direction transverse to the main flow (a novel feature of the proposed method). Mathematical models of fully developed fluid flow and heat transfer in pipes and parallel-plate channels were also considered and solved using one-dimensional FVMs. The results were compared to those yielded by available empirical correlations and also experimental data. Finally, one of the three low-Reynolds-number turbulence models and the 2DP FVM were used to simulate fluid flow and heat transfer in three actual rectangular offset strip-fin plate-fin cores of compact heat exchangers.For fully developed flows, all three low-Reynolds-number turbulence models considered in this work gave results that showed excellent agreement with those yielded by available empirical correlations and also experimental data. For developing fluid flow and heat transfer, the 2DP results compared very well with the 2DE results; however, the 2DP FVM executed 700 to 12,000 times faster than the 2DE FVM for comparable computational grids. In simulations of developing fluid flow and heat transfer in continuous-plate channels and regular arrays of staggered plates, only one of the three low-Reynolds-number turbulence models gave good results. The details of the models, numerical methods, and results, and also some recommendations, are presented and discussed in this thesis." --

Download or read book Performance Optimization of Numerical Simulations of Heat Transfer and Fluid Flow written by Matt Blomquist and published by . This book was released on 2019 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical methods to simulate heat transfer and fluid flow phenomena. These numerical simulations require the solution of large linear algebraic systems that arise from the discretization of governing equations and the number of nodes in the discretized mesh is directly related to the accuracy of the simulation. A finer mesh, one with more nodes, will result in better numerical accuracy. However, the computational resources required to solve the linear systems and the overall solution time of the simulation increases with an increased number of nodes. As practitioners continue to develop more complex simulations that require fine meshes, the need for better methods to solve linear systems becomes particularly important. In recent years, there have been significant advancements in computational hardware that have enabled massive parallelism. Multicore processors, graphics processing units, and increased memory capacity have all lead way to significant performance increases for high-performance computing (HPC) workflows that allow for faster and more accurate numerical simulations. However, many of the legacy algorithms used to solve the linear systems in CFD are not well suited to exploit the parallelism in modern computational hardware. Krylov-subspace methods are an ideal solution to this problem as the Krylov algorithms can be parallelized through single-instruction, multiple data (SIMD) operations. In the current study, the Krylov-subspace methods of Bi-Conjugate Gradients, Generalized Minimum Residual, Bi-Conjugate Gradients Stabilized, and Bi-Conjugate Gradients Stabilized (l) are examined as potential algorithms to improve the solution time for numerical simulations of heat transfer and fluid flow. Each of the Krylov methods will be characterized against the standard, line-by-line Tri-Diagonal Matrix Algorithm using a heat conduction model and a Rayleigh-Bénard Convection model. The numerical experiments using heat conduction will examine the impact of grid size and boundary condition placement for each of the algorithms tested. The Rayleigh-Bénard Convection model will be used to determine the performance improvements of the Krylov methods in Patankar's SIMPLER algorithm. The numerical accuracies of each algorithm will be validated using analytical solutions for the heat conduction model and empirical correlations for the Rayleigh-Bénard Convection model.

Download or read book Modeling of Thermofluid Phenomena in Segmented Network Simulations of Loop Heat Pipes written by Nirmalakanth Jesuthasan and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overarching goal of the work presented in this thesis is to formulate, implement, test, and demonstrate cost-effective mathematical models and numerical solution methods for computer simulations of fluid flow and heat transfer in loop heat pipes (LHPs) operating under steady-state conditions.A segmented network thermofluid model for simulating steady-state operation of conventional LHPs with cylindrical and flat evaporators is proposed. In this model, the vapor-transport line, condenser pipe, and liquid-transport line are divided into longitudinal segments (or control volumes). Quasi-one-dimensional formulations, incorporating semi-empirical correlations for the related single- and two-phase phenomena, are used to iteratively impose balances of mass, momentum, and energy on each of the aforementioned segments, and collectively on the whole LHP. Variations of the thermophysical properties of the working fluid with temperature are taken into account, along with...

Download or read book Numerical Simulation of Fluid Flow and Heat Transfer in Microchannels written by Ningli Liu and published by . This book was released on 2006 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Flow and Heat Transfer in Particulate Systems written by Nasser Saghatoleslami and published by . This book was released on 1996 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study on a Numerical Simulation for Thermal hydraulic Phenomena of Multiphase multicomponent Flows written by 核燃料サイクル開発機構 and published by . This book was released on 2002 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct Numerical Simulation of Flow Separation with Heat Conduction written by Jure Oder and published by . This book was released on 2019 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Current Developments in Numerical Simulation of Flow and Heat Transfer written by Kambiz Vafai and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Laminar Flow and Heat Transfer in Two Dimensional Channels written by Paul D. Hancock and published by . This book was released on 1992 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Current Developments in Numerical Simulation of Flow and Heat Transfer written by James L. S. Chen and published by . This book was released on 1994 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: