Heat-transfer fundamentals

The fundamentals of condensation heat transfer are covered in Volume 1, Chapter 9. 

The normal mechanism for heat transfer in commercial condensers is filmwise condensation. Drop wise condensation will give higher heat-transfer coefficients, but is unpredictable and is not yet considered a practical proposition for the design of condensers for general purposes. 

The basic equations for filmwise condensation were derived by Nusselt (1916), and his equations form the basis for practical condenser design. The basic Nusselt equations are derived in Volume 1, Chapter 9. In the Nusselt model of condensation laminar flow is assumed in the film, and heat transfer is assumed to take place entirely by conduction through the film. In practical condensers the Nusselt model will strictly only apply at low liquid and vapour rates, and where the flowing condensate film is undisturbed. Turbulence can be induced in the liquid film at high liquid rates, and by shear at high vapour rates. This will generally increase the rate of heat transfer over that predicted using the Nusselt model. The effect of vapour shear and film turbulence are discussed in Volume 1, Chapter 9, see also Butterworth (1978) and Taborek (1974). 

Developments in the theory of condensation and their application in condenser design are reviewed by Owen and Lee (1983). 

The physical properties of the condensate for use in the following equations, are evaluated at the average condensate film temperature the mean of the condensing temperature and the tube-wall temperature. 

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W.M. Rohsenow, J.P. Hartnett, E.N. Gani , Handbook of Heat Transfer Fundamentals, McGraw-Hill, NewYork, 1995. 

Kakag, S., Vasiliev, L.L., Bayazitoglu, Y. and Yener, Y., (eds.). Microscale Heat Transfer - Fundamentals and Applications, 2005, Kluwer, The Netherlands. Kavehpour, H.P., Faghri, M. and Asako, Y., Effects of Compressibility and Rarefaction on Gaseous Flows in Microchannels, Numerical Heat Transfer, 1997, Part A, 32, 677-696. 

Bayazitoglu, Y., Tunc, G., Wilson, K., and Tjahjono, I., (2005) Convective Heat Transfer for Single-Phase Gases in MicroChannel Slip Flow Analytical Solutions, presented at NATO Advanced Study Institute, Microscale Heat Transfer - Fundamentals and Applications in Biological and Microelectromechanical Systems, July 18-30, Altin Yunus - Qe me, Izmir, Turkey. 

Bayazitoglu, Y., and Kakac, S., (2005) Flow Regimes in MicroChannel Single-Phase Gaseous Fluid Flow, Microscale Heat Transfer-Fundamentals and Applications, S. Kakae (ed.), Kluwer Academie Publishers, Dordrecht (This publication). 

Microscale Heat Transfer - Fundamentals and Applications in Biological and... 

This volume contains an archival record of the NATO Advanced Institute on Microscale Heat Transfer - Fundamental and Applications in Biological and Microelectromechanical Systems held in Qesme - Izmir, Turkey, July 18-30, 2004. The ASIs are intended to be high-level teaching activity in scientific and technical areas of current concern. In this volume, the reader may find interesting chapters and various Microscale Heat Transfer Fundamental and Applications. 

Y. Bayazitoglu and S. Kakac, Flow regimes in microchaimel single-phase gaseous flow, Microscale Heat Transfer - Fundamentals and Applications in Biological Systems and MEMS, edited by S. Kakac, L. Vasihev, Y. Bayazitoglu, and Y. Yener (Kluwer Academic Publishers, The Netherlands 2005). 

R.M. Cotta, S. Kakag, M.D. Mikhailov, F.V. Castellos, and C.R. (Tardoso, Transient flow and thermal analysis in microfluidics, Microscale Heat Transfer-Fundamentals and Applications in Biological Systems and MEMS, edited by... 

C.B. Sobhan and G.P. Peterson, Microscale and Nanoscale Heat Transfer Fundamentals and Engineering Applications (CRC Press, Florida, 2008). 

Y. Yener, S. Kakag, M.R. Avelino, and T. Okutucu, Single-phase Forced Convection in Micro-channels - a State-of-the-art Review, in S. Kakag, L.L. Vasiliev, Y. Bayazitoglu, Y. Yener. (Eds.), Microscale Heat Transfer -Fundamentals and Applications, NATO ASI Series, Kluwer Academic Publishers, The Netherlands, pp. 1-24 (2005). 

M.N. Ozisik and H.R.B. Orlande, Inverse Heat Transfer Fundamentals and Applications, Taylor and Francis, New York (2000). 

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