Modelling of dropwise condensation on a cylindrical surface including the sweeping effect

Download

index.pdf

Date

2007

Author

Özler, Talip Emrah

Metadata

Show full item record

Item Usage Stats

284
views

130
downloads

The purpose of this study was to analyze the dropwise condensation on a cylindrical surface including the sweeping effect theoretically. For this purpose, first the problem of the equilibrium shape and departure size of drops on the outer surface of a cylinder was formulated. The equations of the surface of the drop were obtained by minimizing (for a given volume) the total energy of the drop which consists of surface and gravitational energy by using the techniques of variational calculus. The departure size of the droplets on a surface at varies angle of inclinations were also determined experimentally. Drop departure size is observed to decrease up to as the surface inclination was decreased up to 90 degree and then it increased up to 180 degree. Mean base heat flux, drop departure rate, sweeping frequency, fraction of covered area, sweeping period, local heat flux and average heat flux for the dropwise condensation on a cylindrical surface including the sweeping effect is formulated and the resulting integral equation was solved by using the finite difference techniques. The results show that drop departure rate and sweeping frequency was strongly affected by the angular position and reached asymptotic value at large angular positions. Comparing the results of the average heat flux values at different diameters show that at larger diameters the average heat flux becomes larger. This is due to the increased sweeping effect at larger diameters.

Subject Keywords

Heat Engines.

URI

http://etd.lib.metu.edu.tr/upload/3/12608440/index.pdf
https://hdl.handle.net/11511/16803

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Theoretical investigation of conjugate condensation heat transfer inside vertical tubes Köse, Serhat; Yeşin, Ahmet Orhan; Department of Mechanical Engineering (2010) Based on the well-known theoretical studies related to the film condensation inside vertical tubes, a known temperature distribution is prescribed as boundary condition at the inner surface of the tube wall. But, in reality, there is a thermal interaction between the condensate fluid and conduction through the wall where the temperature variation along the inner surface of the tube wall is unknown and this unknown temperature profile should be determined by taking account of this interaction. In other words...
Modeling of fluid -vapor interface in the condensation zone of a grooved heat pipe Alipour, Mobin; Dursunkaya, Zafer; Department of Mechanical Engineering (2017) Condensation in grooved heat pipes involves several simultaneous phenomena including vapor-liquid boundaries whose shapes are unknown a priori, fluid flow due to capillary and dispersion pressure gradients and condensation over ultra thin films. In grooved heat pipes, the majority of condensation occurs on fin tops due to the thinner liquid film, having a lower thermal resistance, compared to inside the groove where the fluid is substantially thicker. Majority of the studies in the literature assume an appr...
Analysis of Transient Laminar Forced Convection of Nanofluids in Circular Channels Sert, İsmail Ozan; Sezer Uzol, Nilay; Güvenç Yazıcıoğlu, Almıla; Kakaç, Sadık (2012-11-15) In this study, forced convection heat transfer Characteristics of nanofluids are investigated by numerical analysis of incompressible transient laminar flow in a circular duct under step change in wall temperature and wall heat flux. The thermal responses of the system are obtained by solving energy equation under both transient and steady-state conditions for hydrodynamically fully developed flow. In the analyses, temperature dependent thermo-physical properties are also considered. In the numerical analys...
Numerical analysis of temperature distribution of superconducting coil stack İnanır, Fedai; Bak, Bekir; Yıldız, Şükrü; Keysan, Ozan (null; 2017-11-04) In this study, magneto-thermal studies were carried out by solving Ampere and heat conduction equations together in superconducting coil stacks wounded by coated conductors. The coil stack used in the calculations consists of 4 bobbins in the solenoidal structure and each bobbin has 100 windings. Coated conductors are 12mm in width, 100 µm in thickness and has 100 A critical current density. The two-dimensional temperature distributions of the coil stack for different current amplitudes were obtained. The e...
Optimum spacing between vertical, parallel heat generating boards cooled by natural convection in a fixed volume Saygan, Samet; Yüncü, Hafit; Department of Mechanical Engineering (2014) In this study, the effect of distance between vertical and parallel heat generating plates which are fixed in a given volume on the natural convection to the air between plates is investigated both numerically and experimentally. The conservation equations which represent the constant property air flow in fixed and rectangular cross section channel are solved by the FloEFD software which used the Finite Volume Method and the SIMPLE algorithm. The maximum temperatures of plates are compared with the experime...

Citation Formats

T. E. Özler, “Modelling of dropwise condensation on a cylindrical surface including the sweeping effect,” M.S. - Master of Science, Middle East Technical University, 2007.