On Computational Heat Transfer in Industrial Applications

2013 ◽  
Author(s):  
Bengt Sundén
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Industrial Applications ◽  
Transport Processes ◽  
Heat Transfer Fluid ◽  
Time Period ◽  
Industrial Energy ◽  
Gas Turbine Heat Transfer ◽  
1960S And 1970S ◽  
The 1960S

Industrial energy systems involve many components where fluid flow, heat and mass transfer are the important transport processes. For design and development as well as investigation of innovative ideas, computational methods are of vital importance. Since the early pioneering works (by, e.g., the Spalding group) in the 1960s and 1970s, the development has been tremendous and nowadays CFD (computational fluid dynamics) is an established methodology. During the same time period computer capacities in addition have been brought extensively forward. Although still many topics need further development, applications to industrial problems are constantly increasing. In this paper examples of computational heat transfer, fluid flow and related transport phenmena applied to plate heat exchangers (PHEs), gas turbine heat transfer, and fuel cells are highlighted.

scholarly journals Ethylene- and Propylene-Glycol Based Nanofluids: A Litterature Review on Their Thermophysical Properties and Thermal Performances

2018 ◽  
Vol 8 (11) ◽  
pp. 2311 ◽  
Author(s):  
Ghofrane Sekrani ◽  
Sébastien Poncet
Keyword(s):  
Heat Transfer ◽  
Propylene Glycol ◽  
Thermophysical Properties ◽  
Freezing Point ◽  
Industrial Applications ◽  
Heat Transfer Fluid ◽  
Energy Efficiency Improvement ◽  
Research Perspectives ◽  
Industrial Energy ◽  
Industrial Energy Efficiency

Nanofluids are considered a promising way to improve the heat transfer capability of base fluids. Water is the most commonly-used heat transfer fluid. However, in refrigeration systems, it may be necessary to mix water with either ethylene- or propylene-glycol to lower its freezing point and prevent from ice formation. In the same way, for car radiators or industrial heat exchangers, the boiling point of water can be pushed up by mixing it with glycol-based fluids. The increasing awareness of energy saving and industrial energy efficiency improvement results in the growing interest in ethylene- or propylene-glycol-based nanofluids for applications in various thermal systems. The present paper proposes an extensive review of the most recent and relevant experimental and numerical works on the thermophysical properties and performances of ethylene- or propylene-glycol-based nanofluids. Research perspectives are also provided with the long-term objective that these nanofluids be more widely considered in real industrial applications.

Combined Effects of Temperature and Velocity Jump on the Heat Transfer, Fluid Flow, and Entropy Generation Over a Single Rotating Disk

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Arikoglu ◽  
G. Komurgoz ◽  
I. Ozkol ◽  
A. Y. Gunes
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Entropy Generation ◽  
Rotating Disk ◽  
Heat Transfer Fluid ◽  
Combined Effects ◽  
Jump Conditions ◽  
Governing Equations ◽  
Velocity Jump ◽  
Effects Of Temperature

The present work examines the effects of temperature and velocity jump conditions on heat transfer, fluid flow, and entropy generation. As the physical model, the axially symmetrical steady flow of a Newtonian ambient fluid over a single rotating disk is chosen. The related nonlinear governing equations for flow and thermal fields are reduced to ordinary differential equations by applying so-called classical approach, which was first introduced by von Karman. Instead of a numerical method, a recently developed popular semi numerical-analytical technique; differential transform method is employed to solve the reduced governing equations under the assumptions of velocity and thermal jump conditions on the disk surface. The combined effects of the velocity slip and temperature jump on the thermal and flow fields are investigated in great detail for different values of the nondimensional field parameters. In order to evaluate the efficiency of such rotating fluidic system, the entropy generation equation is derived and nondimensionalized. Additionally, special attention has been given to entropy generation, its characteristic and dependency on various parameters, i.e., group parameter, Kn and Re numbers, etc. It is observed that thermal and velocity jump strongly reduce the magnitude of entropy generation throughout the flow domain. As a result, the efficiency of the related physical system increases. A noticeable objective of this study is to give an open form solution of nonlinear field equations. The reduced recurative form of the governing equations presented gives the reader an opportunity to see the solution in open series form.

Numerical Investigation of Heat Transfer, Fluid Flow and Formation of Emissions in Diesel Engines

2013 ◽  
Author(s):  
Müjdat Firat
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Combustion Engine ◽  
Operating Conditions ◽  
Heat Transfer Fluid ◽  
Nox Emissions ◽  
Combustion Pressure ◽  
Crank Angle ◽  
The Relationship ◽  
Hole Number

The present study has been performed on heat transfer, fluid flow and formation of emissions in a diesel engine by different engine parameters. The analysis aims at an investigation of flow field, heat transfer, combustion pressure and formation of emission by means of numerical simulation which is using as parameter; hole number of injector and crank angle. Numerical simulations are performed using the AVL-FIRE commercial software depending on the crank angle. This software is successfully used in internal combustion engine applications, and its validity has been accepted. In this paper, k-zeta-f is preferred as turbulence model and SIMPLE/PISO used as algorithms. Thus, results are presented with pressure traces, temperature curves and NOx and soot levels for engine operating conditions. In addition, the relationship between the spray behaviors and combustion characteristics including NOx emissions, soot emissions, combustion pressure and temperature were illustrated through this analysis.

Numerical Investigation of Heat Transfer in Rectangular Microchannels Under H2 Boundary Condition During Developing and Fully Developed Laminar Flow

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
V. V. Dharaiya ◽  
S. G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Fluid Flow ◽  
Microfluidic Devices ◽  
Transport Processes ◽  
Uniform Heat Flux ◽  
Data Set ◽  
Nusselt Numbers ◽  
Aspect Ratios

Study of fluid flow characteristics at microscale is gaining importance with shrinking device sizes. Better understanding of fluid flow and heat transfer in microchannels will have important implications in electronic chip cooling, heat exchangers, MEMS, and microfluidic devices. Due to short lengths employed in microchannels, entrance header effects can be significant and need to be investigated. In this work, three dimensional model of microchannels, with aspect ratios (α = a/b) ranging from 0.1 to 10, are numerically simulated using CFD software tool fluent. Heat transfer effects in the entrance region of microchannel are presented by plotting average Nusselt number as a function of nondimensional axial length x*. The numerical simulations with both circumferential and axial uniform heat flux (H2) boundary conditions are validated for existing data set for four wall heat flux case. Large numerical data sets are generated in this work for rectangular cross-sectional microchannels with heating on three walls, two opposing walls, one wall, and two adjacent walls under H2 boundary condition. This information can provide better understanding and insight into the transport processes in the microchannels. Although the results are seen as relevant in microscale applications, they are applicable to any sized channels. Based on the numerical results obtained for the whole range, generalized correlations for Nusselt numbers as a function of channel aspect ratio are presented for all the cases. The predicted correlations for Nusselt numbers can be very useful resource for the design and optimization of microchannel heat sinks and other microfluidic devices.

Review of Artificial Bubble Generation Techniques and Their Suitability for Phenomenological Boiling Studies

2020 ◽  
Author(s):  
Navdeep Singh Dhillon
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Experimental Studies ◽  
Solid Surfaces ◽  
Interfacial Phenomena ◽  
Heat Transfer Fluid ◽  
Bubble Generation ◽  
Multiple Bubbles

Abstract The heterogeneous boiling of liquids on hot surfaces, despite its importance, is an extremely complicated and murky phenomenon. It involves the random probabilistic nucleation of multiple bubbles whose growth, interaction, and departure, further, depends on processes involving heat transfer, fluid flow, and interfacial phenomena. This, and the random tumultuous nature of boiling makes experimental studies of the process extremely difficult. For achieving a phenomenological understanding of boiling, several researchers have relied on experiments involving artificially generated bubbles on solid surfaces. In this paper, we evaluate these methods of artificial bubble generation and explore how closely they replicate actual heterogeneous boiling conditions experienced by bubbles. Based on this, we assess the suitability of these methods for conducting phenomenological boiling studies, and identify their potential advantages and drawbacks.

Fluid Flow and Boiling Heat Transfer in Mini Channels

2010 ◽  
Author(s):  
M. Venkatesan ◽  
M. Aravinthan ◽  
Sarit K. Das ◽  
A. R. Balakrishnan
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Boiling Heat Transfer ◽  
Industrial Applications ◽  
Tube Diameter ◽  
Working Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Mini Channels ◽  
Micro Propulsion

Two phase flows in mini channels occur in many industrial applications such as electronic cooling, compact heat exchangers, compact refrigeration systems and in micro propulsion devices. Due to its significance, research on two phase flow in mini channels has become attractive. However, in recent times a controversy exists whether flow in minichannel is different from macro flow because there are still substantial disagreements among various experimental results. In the present study an experimental investigation is carried out for fluid flow and boiling heat transfer characteristics of mini channels with tube diameters ranging from 1–3mm. The tubes were made of SS with water as the working fluid. The variation in friction factor and Nusselt number with decrease in tube diameter for single phase flow was systematically studied. The point of Onset of Nucelate Boiling (ONB) was identified based on wall temperature profile. The effect of heat flux and mass flux on two phase pressure drop with three different tube diameters during sub cooled boiling were investigated. The results reveal that there is an unmistakable effect of tube diameter on fluid friction and onset of boiling during sub cooled boiling in tubes of mini channel dimensions.

Thermodynamic Analysis of Heat and Fluid Flow in a Microchannel With Internal Fins

2009 ◽  
Author(s):  
Ramesh Narayanaswamy ◽  
Tilak T. Chandratilleke ◽  
Andrew J. L. Foong
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Thermodynamic Analysis ◽  
Entropy Generation ◽  
High Performance ◽  
Numerical Study ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Heat Transfer Fluid ◽  
Internal Fins

Efficient cooling techniques are one of the critical design requirements for maintaining reliable operational characteristics of modern, miniaturised high performance electronic components. Microchannel heat sinks form an integral part of most devices used for thermal management in electronic equipment cooling. A microchannel of square cross section, having internal longitudinal fins is considered for analysis. A numerical study is carried out to investigate the fluid flow and heat transfer characteristics. Three-dimensional numerical simulations are performed on the microchannel in the presence of a hydrodynamically developed, thermally developing laminar flow. Further on, a thermodynamic analysis is carried out, for a range of fin heights and thermophysical parameters, in order to obtain the irreversibilities due to heat transfer and fluid flow within the microchannel. An optimum fin height, corresponding to the thermodynamically optimum conditions that minimize the entropy generation rates has been obtained. The effect of the presence of internal fins on the entropy generated due to heat transfer, fluid friction, and the total entropy generation is also provided.

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