M.S., Mechanical Engineering, Oklahoma State University
B.S., Mechanical Engineering, Oklahoma State University
Regents Professor, Oklahoma State University, July 2000
Honorary Professor of Xi'an Jiaotong University, Xi'an, China, 2009
Fellow of the American Society of Mechanical Engineers (ASME), 1996
Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA), 1993
Editor-in-Chief of Heat Transfer Engineering, published by Taylor and Francis, 1997-present
Heat Transfer Series Editor for CRC Press / Taylor & Francis, 2007-present
Registered Professional Engineer (Oklahoma), 1984
Outstanding Advisor Award, College of Engineering, Oklahoma State University, 2008
Golden Torch Faculty Award for Outstanding Scholarship, Leadership, and Service, Oklahoma State University/National Mortar Board Honor Society, 2003
Regents Distinguished Teaching Award, Oklahoma State University, 1996
Halliburton Excellent Teacher Award, Oklahoma State University, 1987, 1998
Mechanical Engineering Outstanding Faculty Award, Oklahoma State University, 1984, 1990
Heat Transfer in Mini/Micro Channels
Mixed Convection Heat Transfer
Computational Heat Transfer and Fluid Mechanics
Two-Phase Flow Heat Transfer/Pressure Drop/Void Fraction/Flow Visualization in Pipes with Different Orientations
Heat Transfer/Pressure Drop in Mini/Micro Tubes
Heat Transfer/Pressure Drop in the Transition Region (Plain and Enhanced Tubes)
Bubble Phenomena in a Vibrating Fluid Column
Thermal Performance of Pipe
Insulation at Below-Ambient Temperatures
Two-Phase Flow Experimental Studies in Pipes with Different Orientations – Gas-liquid two phase flow being a sub category of multiphase flow phenomenon is extensively incorporated in chemical, nuclear, refrigeration and petroleum industry. Flow patterns, void fraction, pressure drop and heat transfer are essential components of gas-liquid two phase flow and of special interest for industrial operations. The pressure drop and heat transfer in two phase flow is altogether different from its single phase counter part due to the complex nature of the flow patterns and compressibility nature of the gas phase and hence making it difficult to model the gas-liquid two phase phenomenon mathematically. Research on void fraction, pressure drop and heat transfer in two phase flow dates back to 1960’s reporting various models proposed by different investigators. However, till date there exist no single model for the accurate prediction of void fraction, pressure drop and heat transfer independent of the flow patterns, pipe geometry and orientation and the fluid thermo physical properties. The ultimate objective of the present research work is to develop unified models to accurately predict void fraction, pressure drop and heat transfer in two phase flow independent of the aforementioned experimental variables. The existing two-phase flow experimental facility is capable of flow pattern visualization and experimental measurements of the void fraction, pressure drop and heat transfer for any given pipe orientation. So far our research has contributed in the experimental analysis of the two phase flow and development of improved empirical correlations for void fraction and heat transfer in different pipe orientations. Three video clips (Annular Flow-different inclination Angles, Slug Flow–Different Inclination Angles, and Different Flow Patterns–Horizontal Flow) based on this study appear in Chapter 1 (Video Gallery of Flow Phenomena) under Section 1.2 (Two-Phase Flow Patterns in Horizontal Tubes, see pages 1-5 to 1-6 and videos 1.2.14, 1.2.15, and 1.2.16) of the Wolverine Engineering Data Book III. The data book is free and can be accessed through the web site of Wolverine Tube Inc. To access the data book go to http://www.wlv.com/products/databook/db3/DataBookIII.pdf.
Heat Transfer/Pressure Drop in Mini/Micro Tubes – The quest for smaller, faster, and cheaper electronics has surpassed the current air cooled technologies ability to dissipate the heat generated. Forced convection, direct contact, single (liquid) and two-phase flow cooling is investigated using mini/micro tubes. Recent experimentation indicates there is a deviation from classical theory of heat transfer and pressure drop due to scaling and roughness effects from mini to the micro scale. The objectives of this study are to perform systematic pressure drop and heat transfer experiments for different flow rates (laminar-transition-turbulent), heat fluxes and inclination angles in mini and micro tubes with different roughness to gain a fundamental understanding of the important parameters influencing fluid flow and heat transfer in these systems. This is a joint project with Dr. L. M. Tam, Department of Electromechnical Engineering, University of Macau, China and Institute for the Development and Quality, Macau, China. Some of the experiments on this project are being conducted at the University of Macau.
Heat Transfer/Pressure Drop in the Transition Region (Plain and Enhanced Tubes) – An important design problem in industrial heat exchangers arises when flow inside the tubes falls in the transition region, typically for Reynolds numbers as low as 200 to as high as 10,000 depending on the type of inlet configuration. Under these conditions the usually cited correlations for heat transfer and friction factor do not give reliable predictions. The aim of this study is to obtain accurate design correlations for heat transfer and pressure drop (isothermal and non-isothermal) in plain tubes in the transition region for various entry configurations. Both experimental and analytical approaches were used. The results of this study have been summarized and appear in Chapter 5 (Enhanced Single-Phase Turbulent Tube-Side Flows and Heat Transfer) under Section 5.2 (Turbulent and Transition Flows and Heat Transfer in Plain Tubes, see pages 5-4 to 5-13) of the Wolverine Engineering Data Book III. The data book is free and can be accessed through the web site of Wolverine Tube Inc. To access the data book go to http://www.wlv.com/products/databook/db3/DataBookIII.pdf. [PDF of Summary of Transition Flow Research]
The study of single-phase heat transfer and pressure drop (isothermal and non-isothermal) in the transition region inside plain tubes with different inlet configurations has now been extended to include enhanced tubes (helically ribbed tubes) with different rib height, rib pitch, and rib helix angle. This is a joint project with Dr. L. M. Tam, Department of Electromechnical Engineering, University of Macau, China and Institute for the Development and Quality, Macau, China. The experimental facility for this project is located at the University of Macau and experiments are underway for both plain and enhanced tubes. The goal of this project is to quantify the tube-side heat transfer and pressure drop characteristics of enhanced tubes in the transition region for single-phase flow and to study the effect of fin geometry and inlet flow configuration on transition Reynolds number. This study is designed to increase fundamental understanding of transition flows inside commercially available enhanced tubes. The ultimate goal of the project is to develop fundamentally based correlations for predicting single-phase heat transfer and pressure drop inside enhanced tubes for the laminar and transition regions. The results of this study would be of great interest to HVAC industry which uses enhanced tube bundles in flooded evaporators and shell side condensers to increase heat transfer.
Bubble Phenomena in a Vibrating Fluid Column – Bubble column reactors are widely used in chemical industry for carrying out a variety of liquid phase reactions. For relatively fast reactions, there is often a need to improve the mass transfer between the gas and liquid phases. The mass transfer performance is dictated by both the bubble size and bubble rise velocity. One method of influencing both the bubble size and the bubble rise velocity is to subject the liquid phase to vibrations. The objective of this project is to develop an experimental apparatus to test bubble motion in a controlled vibration environment. This shall be a liquid-filled column into which bubbles can be injected, then the entire apparatus shaken and the bubble response measured. The influence of liquid properties, column diameter, liquid height, vibration characteristics (frequency and amplitude), and overall system pressure on the bubble motion and size will be systematically studied.
Thermal
Performance of Pipe Insulation at Below-Ambient Temperatures
–
Mechanical pipe insulation systems are installed around cold cylindrical
surfaces, such as chilled pipes, which often work at below ambient temperatures
in several industrial and commercial building applications. The thermal
performance of pipe insulation systems is affected by local ambient conditions
and might vary gradually with time. Most published data are extrapolated from
flat slab configurations of the insulation materials but the measured thermal
conductivity from flat slabs might over or under estimate the actual thermal
conductivity of cylindrical shaped pipe insulation systems due to radial
configuration and longitudinal split joints. The objective of this project was
to design a novel experimental apparatus to measure the thermal conductivity of
mechanical pipe insulation systems at below ambient temperatures. The new
apparatus was validated with two pipe insulation systems, cellular glass and
Polyisocyanurate (PIR), used to benchmark our measurements against data
available in the public domain. The thermal conductivity of additional three
pipe insulation materials (fiberglass, flexible elastomeric and phenolic) was
also measured at several insulation temperatures at below ambient and in dry
non-condensing ambient conditions and wet condensing conditions. Correlations of
the pipe insulation thermal conductivity were developed based on insulation
specimen average temperature and wall thicknesses. This is a joint project with
Dr. Lorenzo Cremaschi of the Oklahoma State University, School of Mechanical and
Aerospace Engineering.
Photo Gallery (click each photo for larger view)
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Videos (tested only in the versions listed)
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Our new experimental setup is equipped for measuring heat transfer, pressure drop, void fraction, and also conducting flow visualization in air-water flow at any pipe inclination (horizontal to vertical position).
Photo Gallery
(click each photo for larger view)
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Flow
Maps and Flow Patterns (JPG files – best viewed at 125%
zoom, or higher, in your browser)
Videos (tested only in the versions listed)
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Mini/Micro Channel Heat Transfer Laboratory
Photo Gallery
(click each photo for larger view)
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Friction Factor in the Transition Region for Stainless Steel Tubes (JPG files – best viewed at 125% zoom, or higher, in your browser) | ||||||||||||||||||||
Heat Transfer
Engineering,
with Dr. Ghajar as its Editor-in-Chief since 1997, is an international
journal which publishes fifteen times per year by Taylor and Francis. The
journal is aimed at practicing engineers and specialists in the field of
heat transfer and is an unparalleled resource for key advances in the
field of heat transfer. In a clear, easy-to-read format, the journal
encompasses developments in equipment, instrumentation, and practice, and
serves as a prime forum for heat exchanger design, planning, and
operation. In addition to refereed papers of original work,
state-of-the-art reviews, the journal also includes current industry news,
summaries of product literature, accounts of the newest research results,
case studies of actual operating experiences with heat transfer equipment,
heat in history, book reviews, and announcements of meetings and
educational programs. Each volume of the journal contains over
1,300 pages.
COMPROP2 is an interactive computer program for the calculation of the properties of various compressible flows. The software was developed in collaboration with Dr. L. M. Tam (a former Ph.D. student and now with University of Macau). There are six modules in this computer program. The first five modules calculate the properties for: Isentropic Flow, Normal Shock Wave, Oblique Shock Wave, Fanno Flow, and Rayleigh Flow. The last module is for Supersonic Airfoil Analysis. For the first five modules, the user can input data and obtain output through a dialog box or from a graph, which is generated using the flow equations. For the supersonic airfoil analysis, a CAD environment is developed for the user to define the dimensions and shape of an airfoil. The software can then calculate the lift force, the drag force, and the pressure distribution of the airfoil according to the flow Mach number and the airfoil angle of attack. The first version of the software (COMPROP) was developed to support the textbook "Compressible Fluid Flow" by Oosthuizen and Carscallen, McGraw-Hill, 1997. The second version of the software (COMPROP2) is available with the new edition of "Modern Compressible Flow with Historical Perspective" by Anderson, McGraw-Hill, 2003.
COMPROP2 User Guide [PDF] is a 45-page document and was completed in December of 2003. The document is posted on the McGraw-Hill/Anderson site. This web-based resource for COMPROP2 links the program directly to selected topics, examples, and problems in the Anderson book.
Simple Aircraft Gas Turbine Design (SAGTD) is an interactive computer program and can be used for analysis and design of a turbojet engine. This software was developed in collaboration with Dr. R. D. Delahoussaye (OSU’s School of Mechanical and Aerospace Engineering) and Mr. V. V. Nayak (former MS student). The program has modules for the analysis/design of the six major components of a turbojet engine (Inlet, Diffuser, Compressor, Combustor, Turbine, and Nozzle). The analysis can be performed under both constant and variable specific heats assumption. The software was used for several semesters in the Gas Power Systems course thought at Oklahoma State University.
Steady State and
Transient Heat Conduction (SS-T-CONDUCT)
is an interactive computer program and can be used for solving one and two
dimensional steady state and transient heat conduction problems. This software
was developed in collaboration with Mr. H. Al-Matar (former MS student). The
program can handle variety of boundary conditions (constant temperature,
specified heat flux, convection). For the transient solution, both implicit and
explicit schemes can be used. The software is available with the 4th
edition of “Heat and Mass Transfer – Fundamentals and Applications”, by Çengel
and Ghajar, McGraw-Hill, 2010.
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Cengel, Y. A. and Ghajar, A. J.,
Heat and Mass Transfer -
Fundamentals and Applications, 4th Edition, McGraw-Hill, New York, NY, 2010. |
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Heat Transfer Series Editor for Janna, W. S., Engineering Heat Transfer,
3rd Edition, CRC Press/Taylor & Francis, Boca Rotan, FL, 2009. |
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Heat Transfer Series Editor for Dorfman, A. S., Conjugate Problems in
Convective Heat Transfer, CRC Press/Taylor & Francis, Boca Rotan, FL,
2010. |
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Heat
Transfer Series Editor for Orlande, H. R. B., Fudym, O., Maillet, D., and Cotta,
R. M., Thermal Measurements and Inverse Techniques, CRC
Press/Taylor & Francis, Boca Rotan, FL, 2011. |
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Heat Transfer Series Editor for Kraus, A. D., Welty, J. R., and Aziz, A.,
Introduction to Thermal and Fluid Engineering, CRC Press/Taylor &
Francis, Boca Rotan, FL, 2012. |
| [PDF] |
Ghajar, A.
J.
and Tang,
C. C., “Void Fraction and Flow Patterns of Two-Phase Flow in Upward and
Downward Vertical and Horizontal Pipes”, in Advances in Multiphase Flow
and Heat Transfer, Vol. 4, pp. 175-201, edited by L. Cheng and D. Mewes,
Bentham Sciences Publishers, 2012. |
| [PDF] |
Ghajar, A. J. and Tang, C. C., “Advances in Void Fraction, Flow Pattern
Maps, and Non-Boiling Heat Transfer Two-Phase Flow in Pipes with Various
Inclinations”, in Advances in Multiphase Flow and Heat Transfer,
Vol. 1, pp. 1-52, edited by L. Cheng and D. Mewes, Bentham Sciences Publisher
Ltd., 2009. |
| [PDF] |
Ghajar, A. J., “Transitional Flow in Tubes,” Chapter 8 in
Heat and Mass Transfer – A Practical Approach, 3rd Edition, Y. A. Cengel,
McGraw-Hill, New York, NY, pp. 482-490, 2007. |
| [PDF] |
Ghajar, A. J. and Kim, J., “Calculation of Local Inside-Wall Convective
Heat Transfer Parameters from Measurements of the Local Outside-Wall
Temperatures along an Electrically Heated Circular Tube,” in Heat
Transfer Calculations, edited by Myer Kutz,
McGraw-Hill, New York, NY, pp. 23.3-23.27, 2006. |
| [PDF] |
Ghajar, A. J., “Compressible Flow,” Chapter 36 in
The Engineering Handbook, 2nd Edition, edited by R. C. Dorf, CRC
Press, Boca Roton, Florida, pp. 36-1 to 36-17, 2004. |
| [PDF] |
Zurigat, Y. H. and Ghajar, A. J., "Heat Transfer and
Stratification in Sensible Heat Storage Systems,” Chapter 6 in Thermal
Energy Storage Systems and Applications, edited by I. Dincer, and M. A.
Rosen, John Wiley & Sons, UK, pp. 259-301, 2002. |
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Ghajar, A. J. and Tang, C. C., “Void Fraction and Flow Patterns of
Two-phase Gas-Liquid Flow in Various Pipe Inclinations”, Keynote Paper, 7th
International Conference on Heat Transfer, Fluid Mechanics, and Thermodynamics (HEFAT
2010), Antalya, Turkey, July 19-21, 2010. |
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Ghajar, A. J. and Tang, C. C., “Recent Developments in Non-Boiling
Two-Phase Flow Heat Transfer and Void Fraction in Various Pipe Inclinations”,
Invited Talk presented at the 6th International Symposium on Multiphase Flow,
Heat and Mass Transfer, and Energy Conversion (ISMF2009), Xi’an, China,
July 11-15, 2009, the International Conference on Science, Technology and
Innovation for Sustainable Well-Being, Mahasarakham, Thailand, July
23-24, 2009. |
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Ghajar, A. J., “Recent Advances in Non-Boiling Two-Phase Flow Heat
Transfer in Horizontal, Inclined, and Vertical Pipes with Different Flow
Patterns,” Keynote Speaker for the International Iranian Society of
Mechanical Engineers Conference, held at the University of Tehran,
Tehran, Iran, May 20-22, 2009. |
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Ghajar, A. J., “Recent Advances in Non-Boiling Two-Phase
Flow Heat Transfer in Horizontal, Inclined, and Vertical Pipes with Different
Flow Patterns,” Invited Seminar delivered at the Swiss Federal Institute of
Technology, Lausanne, Switzerland, May 18, 2009. |
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Ghajar, A. J. and Tang, C. C., “Importance of Non-Boiling Two-Phase Flow
Heat Transfer in Pipes for Industrial Applications,” Keynote Paper,
Proceedings of the 11th Conference on Process Integration, Modeling and
Optimization for Energy Saving and Pollution Reduction (PRES’08),
Prague, Czech Republic, August 24-28, 2008. |
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Ghajar, A. J. and Tang, C. C., “Recent Advances in
Non-Boiling Two-Phase Flow Heat Transfer in Pipes,” Keynote Paper,
Proceedings of the 5th International Conference on Transport Phenomena in
Multiphase Systems (HEAT 2008), Bialystok, Poland, June 30 – July
3, 2008. |
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Ghajar, A. J., “Recent Advances in Non-Boiling Two-Phase
Flow Heat Transfer in Pipes,” Invited Seminar delivered at the University of
Oklahoma, Department of Mechanical and Aerospace Engineering, Norman,
Oklahoma, October 18, 2007. |
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Ghajar, A. J., “Non-Boiling Heat Transfer in Gas-Liquid
Flow in Pipes – A Tutorial,” Invited Tutorial, Proceedings of the 10th
Brazilian Congress of Thermal Engineering and Sciences (ENCIT 2004),
Rio de Janeiro, Brazil, November 29-December 03, 2004. |
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Ghajar, A. J., “Two-Phase Heat Transfer in Gas-Liquid
Non-Boiling Pipe Flows,” Keynote Paper, Proceedings of the 3rd
International Conference on Heat Transfer, Fluid Mechanics, and Thermodynamics (HEFAT
2004), Cape Town, South Africa, June 21-24, 2004. |
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Ghajar, A. J., “Two-Phase Heat Transfer,” Invited Seminar
delivered at the University of Pretoria, Pretoria, South Africa,
June 18, 2004. |
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Bhagwat, S. M. and Ghajar, A. J., “Similarities and Differences in
the Flow Patterns and Void Fraction in Vertical Upward and Downward Two
Phase Flow”, Experimental Thermal and Fluid Science, Vol. 39, pp. 213-227,
2012. (DOI:10.1016/j.expthermflusci.2012.01.026) |
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Cremaschi, L., Cai, S., Worthington, K. M., and Ghajar, A. J.,
"Measurements of Pipe Insulation Thermal Conductivity at Below Ambient
Temperatures Part 1: Experimental Methodology and Dry Tests (ASHRAE
RP-1356)", Accepted for publication in ASHRAE Transactions,
2012. |
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Tam,
L. M., Tam, H. K., Ghajar, A. J., Ng, W. S., “Heat Transfer
Measurements for a Horizontal Micro-Tube Using Liquid Crystal Thermography”,
Proceedings of the 4th International Symposium on Heat Transfer and
Energy Conservation (ISHTEC2012), Guangzhou, China, January 6-9,
2012. |
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Tam,
H.K., Tam, L. M., Tam, S. C., Chio, C. H., Ghajar, A. J., “New
Optimization Method, the Algorithms of Changes, for Heat Exchanger Design”,
Chinese Journal of Mechanical Engineering, Vol.
25, No. 1, pp. 55-62, 2012. (DOI: 10.3901/CJME.2012.01) |
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Tam,
H. K., Tam, L. M., Ghajar, A. J., Tam, S. C., and Zhang, T., “Use of
Algorithms of Changes for Optimal Fin Geometries of the Internally Micro-fin
Tubes in the Turbulent Region”, Proceedings of 2011 International Workshop
on Heat Transfer Advances for Energy Conservation and Pollution Control
(IWHT2011), Xi’an, China, October 17-20, 2011. |
| [PDF] |
Tam,
H. K., Tam, L. M., Ghajar, A. J., Ng, W. S., Wong, I. W., Leong, K.
F., and Wu, C. K., “The Effect of Inner Surface Roughness and Heating on
Friction Factor in Horizontal Micro-Tubes”, Proceedings of ASME-JSME-KSME
Joint Fluids Engineering Conference 2011(AJK2011-FED), Hamamatsu, Shizuoka,
Japan, July 24-29, 2011. |
| [PDF] |
Tam,
H. K., Tam, L. M., Ghajar, A. J., Sun, C., and Leung, H. Y.,
“Experimental Investigation of the Single-Phase Friction Factor and Heat
Transfer Inside the Horizontal Internally Micro-Fin Tubes in the Transition
Region”, Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference
2011(AJK2011-FED), Hamamatsu, Shizuoka, Japan, July 24-29, 2011. |
| [PDF] |
Tam,
H. K., Tam, L. M., and Ghajar, A. J., “Heat
Transfer Correlation for Two-Phase Flow in Vertical Pipes Using Support
Vector Machines”,
Heat
Transfer Engineering,
Vol. 32, No. 11-12, pp. 1047-1052, 2011. |
| [PDF] |
Godbole, P. V., Tang, C. C., Ghajar, A. J., “Comparison of Void
Fraction Correlations for Different Flow Patterns in Upward Vertical
Two-phase Flow”, Heat Transfer Engineering, Vol. 32, No. 10,
pp. 843-860, 2011. |
| [PDF] |
Bhagwat, S.M. and Ghajar, A.J., “Flow Patterns and Void Fraction in
Downward Two Phase Flow”, Proceedings of the ASME Early Career
Technical Conference (2011ECTC), Fayetteville, Arkansas, March
31-April 2, 2011. |
| [PDF] |
Tang,
C. C. and Ghajar, A. J., “A Mechanistic Heat Transfer Correlation for
Non-Boiling Two-Phase Flow in Horizontal, Inclined and Vertical Pipes”,
Proceedings of ASME/JSME 2011(AJTE2011) 8th Thermal Engineering
Joint Conference, Honolulu, Hawaii, March 14-17, 2011. |
| [PDF] |
Tam,
L. M., Tam, H. K. and Ghajar, A. J., “Simultaneous Heat Transfer and
Pressure Drop Measurements for a Horizontal Micro-Tube”, Proceedings of ASME/JSME
2011(AJTE2011) 8th Thermal Engineering Joint Conference,
Honolulu, Hawaii, March 14-17, 2011. |
| [PDF] |
Tam,
H. K., Tam, L. M. and Ghajar, A. J., “Experimental Analysis of the
Single-Phase Heat Transfer and Friction Factor inside the Horizontally
Micro-Fin Tube”, Proceedings of ASME/JSME 2011(AJTE2011) 8th
Thermal Engineering Joint Conference, Honolulu, Hawaii, March 14-17, 2011. |
| [PDF] |
Ghajar, A. J.,
Tam, L. M., Tam, H. K., and Wen, Q., “The
Effect of Inner Surface Roughness on Friction Factor in Horizontal
Micro-tubes”, Proceedings of 2nd International
Conference on Mechanical and Electronics Engineering (ICMEE 2010),
Vol. 1, pp. 59-63, Kyoto, Japan, August 1-3, 2010. |
| [PDF] |
Tam, H. K., Tam, L. M.,
Ghajar, A. J., and Chu, W. W., “Experimental Analysis of the
Single-Phase Heat Transfer and Friction Factor inside the Horizontal
Internally Micro-Fin Tube”, Proceedings of 2nd International
Conference on Mechanical and Electronics Engineering (ICMEE 2010),
Vol. 1, pp. 44-48, Kyoto, Japan, August 1-3, 2010. |
| [PDF] |
Ghajar, A. J.
and Tang, C. C., “Void Fraction and Flow Patterns of Two-phase
Gas-Liquid Flow in Various Pipe Inclinations”, Keynote Paper, Proceedings
of the 7th International Conference on Heat Transfer, Fluid Mechanics, and
Thermodynamics (HEFAT 2010), pp. 115-129, Antalya, Turkey, July 19-21,
2010. |
| [PDF] |
Yeunyongkul,
P., Sakulchangsatjatai, P., and Ghajar, A. J., “Experimental
Investigation of Closed Loop Oscillating Heat Pipe as the Condenser for
Vapor Compression Refrigeration”, Proceedings of the 13th
International Refrigeration and Air Conditioning Conference at Purdue, Paper # 2102 (8 pages), West
Lafayette, Indiana, July 12-15, 2010. |
| [PDF] |
Ghajar, A. J. and Tang, C. C., “Importance of Non-Boiling Two-Phase Flow
Heat Transfer in Pipes for Industrial Applications”, Heat Transfer
Engineering, Vol. 31, No. 9, pp. 711-732, 2010. |
| [PDF] |
Ghajar, A. J., Tang, C. C., and Cook, W. L., “Experimental Investigation
of Friction Factor in the Transition Region for Water Flow in Minitubes and
Microtubes”, Heat Transfer Engineering, Vol. 31, No. 8,
pp. 646-657, 2010. |
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[PDF]
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Tang,
C. C. and Ghajar, A. J., “A Mechanistic Approach for Heat Transfer
Estimation in Horizontal and Vertical Non-Boiling Two-Phase Pipe Flow,”
Chemical Engineering Transactions, Vol. 18, pp. 123-128, 2009. (DOI:
10.3303/CET0918018) |
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[PDF]
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Tam,
H. K., Tam, L. M., Ghajar, A. J., and Cheong, C. W., “Development of
a Unified Flow Regime Map for a Horizontal Pipe with the Support Vector
Machines”, Proceedings of 2nd International Symposium on Computational
Mechanics (ISCM II) and 12th International Conference on Enhancement and
Promotion of Computational Methods in Engineering and Science (EPMESC XII),
Hong Kong – Macau, China, November 30-December 3, 2009. |
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[PDF]
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Tam,
H. K., Tam, L. M., Ghajar, A. J., and Lei, C. U., “Comparison of
Different Correlating Methods for the Single-Phase Heat Transfer Data in
Laminar and Turbulent Flow Regions”, Proceedings of 2nd International
Symposium on Computational Mechanics (ISCM II) and 12th International
Conference on Enhancement and Promotion of Computational Methods in
Engineering and Science (EPMESC XII), Hong Kong – Macau, China,
November 30-December 3, 2009 |
| [PDF] |
Tam,
L. M., Ghajar, A. J., Tam, H. K., “Contribution Analysis of
Dimensionless Variables for Laminar and Turbulent Flow Convection Heat
Transfer in a Horizontal Tube Using Artificial Neural Network,” Heat
Transfer Engineering, Vol. 29, No. 9, pp. 793-804, 2008. |
| [PDF] |
Tam,
L. M., Ghajar, A. J., Tam, H. K., and Tam, S. C., “Development of a
Heat Transfer Correlation for the Transitional Flow in a Horizontal Tube
using Support Vector Machines,” Proceedings of the 2008 ASME Summer
Heat Transfer Conference, Jacksonville, Florida, August 10-14, 2008. |
| [PDF] |
Tam,
L. M., Ghajar, A. J., Tam, H. K., and Tam, S. C., “Development of a
Flow Regime Map for a Horizontal Pipe with the Multi-Classification Support
Vector Machines,” Proceedings of the 2008 ASME Summer Heat Transfer
Conference, Jacksonville, Florida, August 10-14, 2008. |
| [PDF] |
Tang, C. C. and Ghajar, A. J., “Validation of a General Heat Transfer
Correlation for Non-Boling Two-Phase Flow with Different Flow Patterns and
Pipe Inclination Angles,” Proceedings of the 2007 ASME-JSME Thermal
Engineering Summer Heat Transfer Conference, Vancouver, British
Columbia, Canada, July 8-12, 2007. |
| [PDF] |
Tam, L. M.,
Tam, H. K., Ghajar, A. J., and Tam, S. C., “Factor Analysis for
Forced and Mixed Convection Laminar Heat Transfer in a Horizontal Tube Using
Artificial Neural Network,” Proceedings of the 2007 ASME-JSME Thermal
Engineering Summer Heat Transfer Conference, Vancouver, British
Columbia, Canada, July 8-12, 2007. |
| [PDF] |
Krishnamoorthy,
C., Rao, R. P., and Ghajar, A. J., “Single-Phase Heat Transfer in
Micro-Tubes: A Critical Review,” Proceedings of the 2007 ASME-JSME
Thermal Engineering Summer Heat Transfer Conference, Vancouver,
British Columbia, Canada, July 8-12, 2007. |
| [PDF] |
Krishnamoorthy,
C. and Ghajar, A. J., “Single-Phase Friction Factor in Micro-Tubes: A
Critical Review of Measurements, Instrumentation and Data Reduction
Techniques from 1991-2006,” Proceedings of the 5th
International Conference on Nanochannels, Microchannels and Minichannels,
June 18-20, Puebla, Mexico, 2007. |
| [PDF] |
Ghajar, A.
J.
and Tang, C. C., “Heat Transfer Measurements, Flow Pattern Maps and Flow
Visualization for Non-Boiling Two-Phase Flow in Horizontal and Slightly
Inclined Pipe,” Heat Transfer Engineering, Vol. 28, No. 6, pp.
525-540, 2007. |
| [PDF] |
Woldesemayat,
M. A. and Ghajar, A. J., “Comparison of Void Fraction Correlations
for Different Flow Patterns in Horizontal and Upward Inclined Pipes,”
International Journal of Multiphase Flow, Vol. 33, No. 4, pp.
347-370, 2007. |
| [PDF] |
Tam, H. K.,
Tam, S. C., Ghajar, A. J., and Tam, L. M., “Factor Analysis of
Convective Heat Transfer for a Horizontal Tube in the Turbulent Flow Region
Using Artificial Neural Network,” Proceedings of the International
Conference on Computational Methods in Engineering and Science (EPMESC X),
August 21-23, Sanya, Hainan, China, 2006. |
| [PDF] |
Ghajar, A. J. Kim, J., and Tang, C., “Two-phase Flow Heat Transfer
Measurements and Correlation for the Entire Flow Map in Horizontal Pipes,”
Proceedings of the Thirteenth International Heat Transfer Conference,
Sydney, Australia, August 13-18, 2006. |
| [PDF] |
Ghajar, A. J., Delahoussaye, R. D., and Al-Matar, H., “Development
and Implementation of Interactive/Visual Software for Steady State and
Transient Heat Conduction Problems,” Proceedings of the 2006 American
Society of Engineering Education Annular Conference and Exposition,
Chicago, Illinois, June 18-21, 2006. |
| [PDF] |
Kim, J. and Ghajar, A. J., “A General Heat Transfer Correlation for
Non-Boiling Gas-Liquid Flow with Different Flow Patterns in Horizontal
Pipes,” International Journal of Multiphase Flow, Vol. 32, No.
4, pp. 447-465, 2006. |
| [PDF] |
Tam, L. M. and Ghajar, A. J., “Transitional Heat Transfer in Plain Horizontal Tubes,” Heat Transfer Engineering, Vol. 27, No. 5, pp. 23-38, 2006. |
| [PDF] |
Kim, J.,
Ghajar, A. J., Tang, C., and Foutch, G. L., “Comparison of
Near-Wall Treatment Methods for High Reynolds Number Backward-Facing Step
Flow”, International Journal of Computational Fluid Dynamics,
Vol. 19, No. 7, pp. 493-500, 2005. |
| [PDF] |
Ghajar, A.
J.,
“Non-Boiling Heat Transfer in Gas-Liquid Flow in Pipes – A Tutorial,”
Journal of the Brazilian Society of Mechanical Sciences and Engineering,
Vol. XXVII, No. 1, pp. 46-73, 2005. |
| [PDF] |
Ghajar, A. J.
and
Kim, J., “A Non-Boiling Two-Phase Flow Heat Transfer Correlation for
Different Flow Patterns and Pipe Inclination Angles,” Proceedings of
the 2005 ASME Summer Heat Transfer Conference, San Francisco,
California, July 17-22, 2005. |
| [PDF] |
Ghajar, A. J.,
Delahoussaye, R. D., and Nayak, V. V., “Development and Implementation of
Interactive/Visual Software for Simple Aircraft Gas Turbine Design,”
Proceedings of the 2005 American Society of Engineering Education Annular
Conference and Exposition, Portland, Oregon, June 12-15, 2005. |
| [PDF] |
Ghajar, A. J., Tam, L. M., and Tam, S. K., “Improved Heat Transfer
Correlation in the Transition Region for a Circular Tube with Three Inlet
Configurations Using Artificial Neural Networks,” Heat Transfer
Engineering, Vol. 25, No. 2, pp. 30-40, 2004. |
| [PDF] |
Sofyan, Y., Ghajar, A. J., and Gasem,
K. A. M., “Multiphase Equilibrium Calculations Using Gibbs Minimization
Techniques,” Industrial & Engineering Chemistry Research,
Vol. 42, No. 16, pp. 3786-3801, 2003. |
| [PDF] |
Ghajar, A. J., Tam, L. M., and Tam, H.
K., 2003 “Heat Transfer Correlation for Two Phase Flow in Vertical Pipes Using
Artificial Neural Network,” Proceedings of
2003 ASME International Mechanical Engineering Congress and R&D Expo,
November 15-21, 2003,Washington, D.C. |
| [PDF] |
Ghajar, A. J., Tam, L. M., and Tam,
S.C., 2003 “A Simple Heat Transfer Correlation for Three Inlet Configurations
Using Artificial Neural Network in the Complex Transition Flow Regime,”
Proceedings of the 2003 ASME Summer Heat Transfer Conference, July
21-23, 2003, Las Vegas, Nevada. |
| [PDF] |
Sofyan, Y., Ghajar, A. J., and Gasem,
K. A. M., “A Systematic Method to Predict Cloud Point Temperature and Solid
Precipitation,” Petroleum Science and Technology, Vol. 21, Nos. 3
& 4, pp.409-424, 2003. |
| [PDF] |
Ghajar,
A. J., Tam, L. M., and Tam, S. K., “A New Heat Transfer Correlation in the
Transition Region for a Horizontal Pipe with a Reentrant Inlet – Using
Artificial Neural Network,” Heat Transfer 2002, Proceedings of the
Twelfth International Heat Transfer Conference, Elsevier,
pp. 189-194, 2002. |
| [PDF] |
Kim, D.
and Ghajar, A. J., "Heat
Transfer Measurements and Correlations for Air-Water Flow of Different Flow
Patterns in a Horizontal Pipe," Experimental
Thermal and Fluid Science, Vol. 25, No. 8, pp. 659-676,
2002. |
| [PDF] |
Tam, L. M., Ghajar,
A. J., and Pau, C. W., “Compressible Flow Software for Properties
Calculations and Airfoil Analysis,” Proceedings of the Eighth International Conference of Enhancement and Promotion of Computing Methods for
Engineering and Science (EPMESC’ VIII), editors L. Shaopei et al.,
July 25-28, Shanghai, China, 2001. |
| [PDF] |
Kim, D., Ghajar, A. J., and Dougherty, R. L., "Robust Heat-Transfer
Correlations for Turbulent Gas-Liquid Flow in Vertical Pipes," Journal
of Thermophysics and Heat Transfer, Vol. 14, No. 4, pp. 574-578,
2000. |
| [PDF] |
Whitelock, D. P., Brusewitz, G. H. and Ghajar, A. J., "Thermal/Physical
Properties Affect Predicted Weight Loss of Fresh Peaches," Transactions
of the ASAE, Vol. 42, No. 4, pp. 1047-1053, 1999. |
| [PDF] |
Kim, D., Ghajar, A. J., Dougherty, R. L., and Ryali, V. K.,"Comparison
of 20 Two-Phase Heat Transfer Correlations with Seven Sets of Experimental
Data, Including Flow Pattern and Tube Inclination Effects," Heat
Transfer Engineering, Vol. 20, No. 1, pp. 15-40, 1999. |
| [PDF] |
Tam, L. M. and Ghajar, A. J., "The Unusual Behavior of Local
Heat Transfer Coefficient in a Circular Tube with a Bell-Mouth Inlet,"
Experimental Thermal and Fluid Science, Vol. 16, No. 3, pp. 187-194, 1998.
|
| [PDF] |
Tam, L. M. and Ghajar, A. J., "Effect of Inlet Geometry and Heating
on the Fully Developed Friction Factor in the Transition Region of a Horizontal
Tube," Experimental Thermal and Fluid Science, Vol. 15, No. 1, pp. 52-64, 1997.
|
| [PDF] |
Tang, W. and Ghajar, A. J., "Experimental Study of
Conjugate Heat Transfer in a Horizontal Channel with Discrete Heated Cubic
Blocks," Thermal Management of Hand-Held, Wearable, and Portable Electronics,
eds. C. H. Amon et al., ASME, HTD-Vol. 343, pp. 91-102, 1997. |
| [PDF] |
Cutbirth, J. M. and Ghajar, A. J., "Thermal and
Hydraulic Analysis of a High Flux Heat Exchanger," Thermal Management of Commercial
and Military Electronics, eds. R. Schmidt et al. ASME, HTD-Vol. 329, pp. 187-196, 1996. |
| [PDF] |
Arabzadeh, M., Kim, D. and Ghajar, A. J.,
"Experimental Study of Geometric Effects on Forced Air-Cooling of Regular
In-Line Array of Electronic Components," Proceedings of the ASME/JSME Thermal
Engineering Joint Conference, eds. L.S. Fletcher and T. Aihara,
ASME, Vol. 4, pp. 231-239, 1995. |
| [PDF] |
Ghajar, A. J., Tang, W. C. and Beam, J. E., "Methodology for
Comparison of Hydraulic and Thermal Performance of Alternative Heat Transfer
Fluids in Complex Systems," Heat Transfer Engineering, Vol. 16,
No. 1, pp. 60-72, 1995. |
| [PDF] |
Ghajar, A. J. and Tam, L. M., "Flow Regime Map for a Horizontal
Pipe with Uniform Heat Flux and Three Different Inlet Configurations,"
Experimental Thermal and Fluid Science, Vol. 10, No. 3, pp.
287-297, 1995. |
| [PDF] |
Bang, K., Ghajar, A. J. and Komanduri, R., "The Effect of Substrate
Surface Temperature on the Morphology and Quality of Diamond Films Produced
by the Oxy-Acetylene Combustion Method," Thin Solid Films,
Vol. 238, pp. 172-183, February 1994. |
| [PDF] |
Ghajar, A. J. and Tam, L. M., "Heat Transfer Measurements and
Correlations in the Transition Region for a Circular Tube with Three Different
Inlet Configurations," Experimental Thermal and Fluid Science,
Vol. 8, No. 1, pp. 79-90, 1994. |
| [PDF] |
Ghajar, A. J. and Bang, K., "Parametric Effects on the Substrate
Temperature Profile in Oxy-Acetylene Flames,"
Heat Transfer Engineering,
Vol. 14, No. 3, pp. 48-59, 1993. |
| [PDF] |
Ghajar, A. J. and Bang, K., "Experimental and Analytical Studies
of Different Methods for Producing Stratified Flows,"
Energy – The
International Journal, Vol. 18, No. 4, pp. 323-334, 1993. |
| [PDF] |
Arabzadeh, M., Ogden, E. L. and Ghajar, A. J.,
"Conduction Heat Transfer Measurements for an Array of Surface Mounted Heated
Components," Enhanced Cooling Technologies for Electronics Applications,
eds. S. V. Garimella, et al., ASME, HTD-Vol. 263, pp. 69-78, 1993. |
| [PDF] |
Ghajar, A. J. and Madon, K. F., "Pressure Drop Measurements in
the Transition Region for a Circular Tube with Different Inlet Configurations,"
Experimental Thermal and Fluid Science, Vol. 5, No. 1, pp.
129-135, 1992. |
| [PDF] |
Abu-Hamdan, M. G., Zurigat, Y. H. and Ghajar, A. J., "An Experimental
Study of a Stratified Thermal Storage Under Variable Inlet Temperature
for Different Inlet Designs,"
International Journal of Heat and Mass
Transfer, Vol. 35, No. 8, pp. 1927-1934, 1992. |
| [PDF] |
Zurigat, Y. H., Liche, P. R. and Ghajar, A. J., "Influence of
Inlet Geometry on Mixing in Thermocline Thermal Energy Storage,"
International
Journal of Heat and Mass Transfer, Vol. 34, No. 1, pp. 115-125,
1991. |
| [PDF] |
Ghajar, A. J. and Zurigat, Y. H., "Microcomputer-Assisted Heat
Transfer Measurements/Analysis in a Circular Tube,"
International
Journal of Applied Engineering Education, Vol. 7, No. 2, pp. 125-134,
1991. |
| [PDF] |
Ghajar, A. J. and Zurigat, Y. H., "Numerical Study of the Effect
of Inlet Geometry on Stratification in Thermal Energy Storage," Numerical
Heat Transfer, Part A: Applications, Vol. 19, No. 1, pp. 65-83,
1991. |
| [PDF] |
Wang, Y. and Ghajar, A. J., "Effect of Component
Geometry and Layout on Flow Distribution for Surface Mounted Electronic
Components: A Smoke Flow Visualization Study," Heat Transfer Enhancement in
Electronics Cooling, eds. S. H. Bhavnani and M. Greiner, ASME,
HTD-Vol. 183, pp. 25-31, 1991. |
| [PDF] |
Zurigat, Y. H. and Ghajar, A. J., "Comparative Study of Weighted
Upwind and Second Order Upwind Difference Schemes,"
Numerical Heat
Transfer, Part B: Fundamentals, Vol. 18, No. 1, pp. 61-79, 1990. |
| [PDF] |
Zurigat, Y. H., Bang, K. and Ghajar, A. J., "Methods for Producing
Linear Density Gradients in Laboratory Tanks,"
Energy - The International
Journal, Vol. 15, No. 1, pp. 23-34, 1990. |
| [PDF] |
Ghajar, A.
J.
and Raza, K., "Mass Transfer Analogy for Heat Transfer Experiments in
Thermal Storage," International Communications in Heat and Mass
Transfer, Vol. 17, No. 1, pp. 79-91, 1990. |
| [PDF] |
Zurigat, Y. H., Maloney, K. J. and Ghajar, A. J., "A Comparison
Study of One-Dimensional Models for Stratified Thermal Storage Tanks,"
ASME Journal of Solar Energy Engineering, Vol. 111, No. 3,
pp. 204-210, 1989. |
| [PDF] |
Ghajar, A. J. and Yoon, H. K., "A Heat Transfer Correlation for
Viscoelastic Turbulent Pipe Flows," Chemical Engineering
Communications, Vol. 78, pp. 167-177, 1989. |
| [PDF] |
Toh, K. H. and Ghajar, A. J., "Heat Transfer in Thermal Entrance
Region for Viscoelastic Fluids in Turbulent Pipe Flows," International
Journal of Heat and Mass Transfer, Vol. 31, No. 6, pp. 1261-1267,
1988. |
| [PDF] |
Zurigat, Y. H., Ghajar, A. J. and Moretti, P. M., "Stratified
Thermal Storage Tank Inlet Mixing Characterization," Applied Energy,
Vol. 30, No. 2, pp. 99-111, 1988. |
| [PDF] |
Ghajar, A. J. and Azar, M. Y., "Empirical Correlations for Friction
Factor in Drag-Reducing Turbulent Pipe Flows," International
Communications in Heat and Mass Transfer, Vol. 15, No. 6, pp.
705-718, 1988. |
| [PDF] |
Yoon, H.
K. and Ghajar, A. J., "Heat Eddy Diffusivity for Viscoelastic
Turbulent Pipe Flows," International Communications in Heat and Mass
Transfer, Vol. 14, No. 3, pp. 237-249, 1987. |
| [PDF] |
Yoon, H.
K. and Ghajar, A. J., "A Note on the Powell-Eyring Fluid Model,"
International Communications in Heat and Mass Transfer, Vol. 14,
No. 4, pp. 381-390, 1987. |
| [PDF] |
Jakobsson, H. Th. and Ghajar, A. J., "Numerical Solutions of Heat
Conduction and Simple Fluid Flow Problems," International
Communications in Heat and Mass Transfer, Vol. 14, No. 1, pp. 67-79,
1987. |
| [PDF] |
Ghajar, A. J. and Asadi, A., "Improved Forced Convective Heat
Transfer Correlations for Liquids in the Near-Critical Region,"
AIAA
Journal, Vol. 24, No. 12, pp. 2030-2037, 1986. |
| [PDF] |
Zurigat, Y. H. and Ghajar, A. J., "Computer Simulation of Woodstove
Thermal Storage System," Energy Conversion and Management,
Vol. 26, No. 2, pp. 165-173, 1986. |
| [PDF] |
Oppel, F. J., Ghajar, A. J. and Moretti, P. M., "A Numerical
and Experimental Study of Stratified Thermal Storage,"
ASHRAE Transactions,
Vol. 92 (part 2), pp. 293-309, 1986. |
| [PDF] |
Oppel, F. J., Ghajar, A. J. and Moretti, P. M., "Computer Simulation
of Stratified Heat Storage," Applied Energy, Vol. 23, No.
3, pp. 205-224, 1986. |
| [PDF] |
Yoon, H.
K. and Ghajar, A. J., "A New Heat Eddy Diffusivity Equation for
Calculation of Heat Transfer to Drag Reducing Turbulent Pipe Flows,"
International Communications in Heat and Mass Transfer, Vol. 13, No.
4, pp. 449-464, 1986. |
| [PDF] |
Asgeirsson, L. S. and Ghajar, A. J., "Prediction of Thermal
Conductivity and Viscosity for Some Fluids in the Near-Critical Region,"
Chemical Engineering Communications, Vol. 43, Nos. 1-3, pp.
165-184, 1986. |
| [PDF] |
Kanchanalakshana, D. and Ghajar, A. J., "An Improved Falling Sphere
Viscometer for Intermediate Concentrations of Viscoelastic Fluids,"
International Communications in Heat and Mass Transfer, Vol. 13, No.
2, pp. 219-233, 1986. |
| [PDF] |
Maxwell, M. J. and Ghajar, A. J., "Laminar Forced Convective
Heat Transfer with Varying Properties in the Entrance Region of Flat Rectangular
Ducts," Heat Transfer Engineering, Vol. 6, No. 4, pp. 31-38,
1985. |
| [PDF] |
Ghorbani-Tari, S. and Ghajar, A. J., "Improved Free Convective
Heat Transfer Correlations in the Near-Critical Region," AIAA Journal,
Vol. 23, No. 10, pp. 1647-1649, 1985. |
| [PDF] |
Pilcher, K. R. and Ghajar, A. J., "Thermal Storage Mass Enhances
Woodstove Combustion and Reduces Pollution,"
Energy - The International
Journal, Vol. 10, No. 10, pp. 1151-1157, 1985. |
| [PDF] |
Yoon, H. K. and Ghajar, A. J., "An Analysis of the Heat Transfer
to Drag Reducing Turbulent Pipe Flows,"
ASME Journal of Heat Transfer,
Vol. 106, No. 4, pp. 898-900, 1984. |
| [PDF] |
Ghajar, A. J. and Parker, J. D., "Reference Temperatures for
Supercritical Laminar Free Convection on a Vertical Flat Plate,"
ASME
Journal of Heat Transfer, Vol. 103, No. 4, pp. 613-616, 1981. |
| [PDF] |
Ghajar, A. J. and Parker, J. D., "Laminar-Free Convection in the
Supercritical Region with Variable Properties," In the Proceedings of
the 1980 Heat Transfer and Fluid Mechanics Institute, eds. M.
Gerstein and P. R. Choudhury, Stanford University Press, pp. 196-208, 1980. |
| [PDF] |
Ghajar, A. J. and Tiederman, W. G., "Prediction of Heat Transfer
Coefficients in Drag Reducing Turbulent Pipe Flows," AIChE Journal,
Vol. 23, No. 1, pp. 128-131, 1977. |
