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Sadik Kakac

Bio: Sadik Kakac is an academic researcher from TOBB University of Economics and Technology. The author has contributed to research in topics: Heat transfer & Two-phase flow. The author has an hindex of 34, co-authored 163 publications receiving 9371 citations. Previous affiliations of Sadik Kakac include Turkish Academy of Sciences & University of Miami.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors summarized the important published articles on the enhancement of the forced convection heat transfer with nanofluids, including simulations, simulations, and experimental results.

1,738 citations

Book
01 Jan 1987
TL;DR: In this paper, the effect of temperature-dependent Fluid properties on convective heat transfer has been investigated in the context of closed-loop convection in Ducts and cross-flow convection over Rod Bundles.
Abstract: Basics of Heat Transfer (S. Kakac & Y. Yener) External Flow Forced Convection (R. Pletcher) Laminar Convective Heat Transfer in Ducts (R. Shah & M. Bhatti) Turbulent and Transition Flow Convective Heat Transfer in Ducts (M. Bhatti & R. Shah) Convective Heat Transfer in Curved Ducts (R. Shah & S. Joshi) Convective Heat Transfer in Cross Flow (A. Zukauskas) Convective Heat Transfer over Rod Bundles (K. Rehme) Convective Heat Transfer in Liquid Metals (C. Reed) Convective Heat Transfer with Electric and Magnetic Fields (F. Kulacki et al.) Convective Heat Transfer in Bends and Fittings (S. Joshi & R. Shah) Transient Forced Convection in Ducts (Y. Yener & S. Kakac) Basics of Natural Convection (Y. Jaluria) Natural Convection in Enclosures (K. Yang) Mixed Convection in External Flow (T. Chen & B. Armaly) Mixed Convection in Internal Flow (W. Aung) Convective Heat Transfer in Porous Media (A. Bejan) Enhancement of Single-phase Heat Transfer (R. Webb) The Effect of Temperature-dependent Fluid Properties on Convective Heat Transfer (S. Kakac) Interaction of Radiation with Convection (M. Ozisik) Non-Newtonian Fluid Flow and Heat Transfer (T. Irvine, Jr & J. Karni) Fouling with Convective Heat Transfer (W. Marner & J. Suitor) Thermophysical Properties (P. Liley) Index.

1,589 citations

Book
29 Dec 1997
TL;DR: In this paper, the effect of variable physical properties in Turbulent Forced Convection in Smooth Straight Noncircular Ducts and Turbulents Flow in smooth Straight Non-circular ducts is discussed.
Abstract: CLASSIFICATIONS OF HEAT EXCHANGERS Introduction Recuperation and Regeneration Transfer Processes Geometry of Construction Heat Transfer Mechanisms Flow Arrangements Applications Selection of Heat Exchangers BASIC DESIGN METHODS OF HEAT EXCHANGERS Introduction Arrangement of Flow Path in Heat Exchangers Basic Equations in Design Overall Heat Transfer Coefficient The LMTD Method for Heat Exchangers Analysis The e-NTU Method for Heat Exchangers Analysis Heat Exchanger Design Calculation Variable Overall Heat Transfer Coefficient Heat Exchanger Design Methodology FORCED CONVECTION CORRELATIONS FOR SINGLE-PHASE SIDE OF HEAT EXCHANGERS Introduction Laminar Forced Convection The Effect of Variable Physical Properties Turbulent Forced Convection Turbulent Flow in Smooth Straight Noncircular Ducts The Effect of Variable Physical Properties in Turbulent Forced Convection Summary of Forced Convection in Straight Ducts Heat Transfer from Smooth-Tube Bundles Heat Transfer in Helical Coils and Spirals Heat Transfer in Bends HEAT EXCHANGER PRESSURE DROP AND PUMPING POWER Introduction Tube-Side Pressure Drop Pressure Drop in Tube Bundles in Cross-Flow Pressure Drop in Helical and Spiral Coils Pressure Drop in Bends and Fittings Pressure Drop for Abrupt Contraction, Expansion, and Momentum Change Heat Transfer and Pumping Power Relationship FOULING OF HEAT EXCHANGERS Introduction Basic Considerations Effects of Fouling Aspects of Fouling Design of Heat Exchangers Subject to Fouling Operation of Heat Exchangers Subject to Fouling Techniques to Control Fouling DOUBLE-PIPE HEAT EXCHANGERS Introduction Thermal and Hydraulic Design of Inner Tube Thermal and Hydraulic Analysis of Annulus Parallel-Series Arrangements of Hairpins Total Pressure Drop Design and Operational Features DESIGN CORRELATIONS FOR CONDENSERS AND EVAPORATORS Introduction Condensation Film Condensation on a Single Horizontal Tube Film Condensation on Tube Bundles Condensation Inside Tubes Flow Boiling SHELL-AND-TUBE HEAT EXCHANGERS Introduction Basic Components Basic Design Procedure of a Heat Exchanger Shell-Side Heat Transfer and Pressure Drop COMPACT HEAT EXCHANGERS Introduction Heat Transfer and Pressure Drop THE GASKETED-PLATE HEAT EXCHANGERS Introduction Mechanical Features Operational Characteristics Passes and Flow Arrangements Applications Heat Transfer and Pressure Drop Calculations Thermal Performance CONDENSERS AND EVAPORATORS Introduction Shell and Tube Condensers Steam Turbine Exhaust Condensers Plate Condensers Air Cooled Condensers Direct Contact Condensers Thermal Design of Shell-and-Tube Condensers Design and Operational Considerations Condensers for Refrigeration and Air Conditioning Evaporators for Refrigeration and Air Conditioning Thermal Analysis Standards for Evaporators and Condensers APPENDICES Physical Properties of Metals and Nonmetals Physical Properties of Air, Water, Liquid Metals, and Refrigerants Each chapter also contains sections of Nomenclature, References, and Problems

1,120 citations

Journal ArticleDOI
TL;DR: In this paper, a 2D mathematical model for the entire sandwich of a proton-exchange membrane fuel cell including the gas channels was developed, where a self-consistent model for porous media was used for the equations describing transport phenomena in the membrane, catalyst layers, and gas diffusers, while standard equations of Navier-Stokes, energy transport, continuity, and species concentrations are solved in the gas channel.
Abstract: A 2-D mathematical model for the entire sandwich of a proton-exchange membrane fuel cell including the gas channels was developed The self-consistent model for porous media was used for the equations describing transport phenomena in the membrane, catalyst layers, and gas diffusers, while standard equations of Navier-Stokes, energy transport, continuity, and species concentrations are solved in the gas channels A special handling of the transport equations enabled us to use the same numerical method in the unified domain consisting of the gas channels, gas diffusers, catalyst layers and membrane It also eliminated the need to prescribe arbitrary or approximate boundary conditions at the interfaces between different parts of the fuel cell sandwich By solving transport equations, as well as the equations for electrochemical reactions and current density with the membrane phase potential, polarization curves under various operating conditions were obtained Modeling results compare very well with experimental results from the literature Oxygen and water vapor mole fraction distributions in the coupled cathode gas channel-gas diffuser were studied for various operating current densities Liquid water velocity distributions in the membrane and influences of various parameters on the cell performance were also obtained

595 citations

Journal ArticleDOI
TL;DR: In this article, effective thermal conductivity models of nanofluids are reviewed and comparisons between experimental findings and theoretical predictions are made, and the results show that there exist significant discrepancies among the experimental data available and between the experimental results and the theoretical model predictions.
Abstract: Adding small particles into a fluid in cooling and heating processes is one of the methods to increase the rate of heat transfer by convection between the fluid and the surface. In the past decade, a new class of fluids called nanofluids, in which particles of size 1–100 nm with high thermal conductivity are suspended in a conventional heat transfer base fluid, have been developed. It has been shown that nanofluids containing a small amount of metallic or nonmetallic particles, such as Al2O3, CuO, Cu, SiO2, TiO2, have increased thermal conductivity compared with the thermal conductivity of the base fluid. In this work, effective thermal conductivity models of nanofluids are reviewed and comparisons between experimental findings and theoretical predictions are made. The results show that there exist significant discrepancies among the experimental data available and between the experimental findings and the theoretical model predictions.

550 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors considered seven slip mechanisms that can produce a relative velocity between the nanoparticles and the base fluid and concluded that only Brownian diffusion and thermophoresis are important slip mechanisms in nanofluids.
Abstract: Nanofluids are engineered colloids made of a base fluid and nanoparticles (1-100 nm) Nanofluids have higher thermal conductivity' and single-phase heat transfer coefficients than their base fluids In particular the heat transfer coefficient increases appear to go beyond the mere thermal-conductivity effect, and cannot be predicted by traditional pure-fluid correlations such as Dittus-Boelter's In the nanofluid literature this behavior is generally attributed to thermal dispersion and intensified turbulence, brought about by nanoparticle motion To test the validity of this assumption, we have considered seven slip mechanisms that can produce a relative velocity between the nanoparticles and the base fluid These are inertia, Brownian diffusion, thermophoresis, diffusioplwresis, Magnus effect, fluid drainage, and gravity We concluded that, of these seven, only Brownian diffusion and thermophoresis are important slip mechanisms in nanofluids Based on this finding, we developed a two-component four-equation nonhomogeneous equilibrium model for mass, momentum, and heat transport in nanofluids A nondimensional analysis of the equations suggests that energy transfer by nanoparticle dispersion is negligible, and thus cannot explain the abnormal heat transfer coefficient increases Furthermore, a comparison of the nanoparticle and turbulent eddy time and length scales clearly indicates that the nanoparticles move homogeneously with the fluid in the presence of turbulent eddies so an effect on turbulence intensity is also doubtful Thus, we propose an alternative explanation for the abnormal heat transfer coefficient increases: the nanofluid properties may vary significantly within the boundary layer because of the effect of the temperature gradient and thermophoresis For a heated fluid, these effects can result in a significant decrease of viscosity within the boundary layer, thus leading to heat transfer enhancement A correlation structure that captures these effects is proposed

5,329 citations

Journal ArticleDOI
TL;DR: The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high energy storage density and the isothermal nature of the storage process.
Abstract: The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal-storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.

4,482 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarized the important published articles on the enhancement of the forced convection heat transfer with nanofluids, including simulations, simulations, and experimental results.

1,738 citations

Journal ArticleDOI
TL;DR: In this article, a similarity solution is presented which depends on the Prandtl number Pr, Lewis number Le, Brownian motion number Nb and thermophoresis number Nt.

1,565 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the recent progress on the study of nanofluids, such as the preparation methods, the evaluation methods for the stability of nanometrics, and the ways to enhance the stability for nanofl fluids, and presented the broad range of current and future applications in various fields including energy and mechanical and biomedical fields.
Abstract: Nanofluids, the fluid suspensions of nanomaterials, have shown many interesting properties, and the distinctive features offer unprecedented potential for many applications. This paper summarizes the recent progress on the study of nanofluids, such as the preparation methods, the evaluation methods for the stability of nanofluids, and the ways to enhance the stability for nanofluids, the stability mechanisms of nanofluids, and presents the broad range of current and future applications in various fields including energy and mechanical and biomedical fields. At last, the paper identifies the opportunities for future research.

1,320 citations