Modeling of fluid -vapor interface in the condensation zone of a grooved heat pipe

Download

index.pdf

Date

2017

Author

Alipour, Mobin

Metadata

Show full item record

Item Usage Stats

224
views

138
downloads

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 approximate profile for the liquid film surface and apply an integral balance for conservation laws, including the effect of the capillary pressure only. In addition, this approximate profile is matched with the liquid profile inside the groove, which serves as a boundary condition. In the current study, the effect of a slope dependent disjoining pressure and the matching conditions with the groove are investigated using a comprehensive model. The results suggest that for small temperature differences and small slopes, the effect of dispersion pressure is non negligible and beyond limiting values of edge slope angles, the disjoining effect precludes solutions where the fin top film matches the groove in a smooth transition. In addition bifurcation manner is found for the results. Their physical availability is examined in this study. This analysis results suggested that the second set of answers which is found because of bifurcation, despite its mathematical validity, could not be physically valid.

Subject Keywords

Heat pipes., Heat, Heat-transfer media., Electronics

URI

http://etd.lib.metu.edu.tr/upload/12621571/index.pdf
https://hdl.handle.net/11511/26871

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Numerical simulation of thermal convection under the influence of a magnetic field by using solenoidal bases Yarımpabuç, Durmuş; Tarman, Işık Hakan; Department of Engineering Sciences (2011) The effect of an imposed magnetic field on the thermal convection between rigid plates heated from below under the influence of gravity is numerically simulated in a computational domain with periodic horizontal extent. The numerical technique is based on solenoidal basis functions satisfying the boundary conditions for both velocity and induced magnetic field. The expansion bases for the thermal field are also constructed to satisfy the boundary conditions. The governing partial differential equations are ...
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...
Performance of rectangular fins on a vertical base in free convection heat transfer Yazıcıoğlu, Burak; Yüncü, Hafit; Department of Mechanical Engineering (2005) The steady-state natural convection heat transfer from vertical rectangular fins extending perpendicularly from vertical rectangular base was investigated experimentally. The effects of geometric parameters and base-to-ambient temperature difference on the heat transfer performance of fin arrays were observed and the optimum fin separation values were determined. Two similar experimental set-ups were employed during experiments in order to take measurements from 30 different fin configurations having fin le...
Vibration reduction of helicopter tail shaft by using dry friction dampers Özaydın, Onur; Ciğeroğlu, Ender; Department of Mechanical Engineering (2017) Tail Drive Shaft is a power transmission component of a helicopter which constructs the link between the main gearbox and the tail rotor. In many helicopter designs, tail shafts are working in supercritical speeds. In order to limit resonance vibrations of tail drive shaft occurring as a drawback of a supercritical design, dry friction dampers are used by helicopter manufacturers. In this study, vibration reduction of supercritical helicopter tail drive shaft by utilizing dry friction dampers is studied. Eu...
3-D numerical simulations of fluid flow and heat transfer in various micro conduits Turgay, Metin Bilgehan; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2017) In this work, it is aimed to investigate the effect of roughness geometrical properties and configurations on laminar flow and heat transfer characteristics in microchannels, numerically. For this purpose, two-dimensional parallel plate, and three-dimensional trapezoidal microchannels with different roughness properties are modeled along with the smooth ones. Fluid flow and heat transfer simulations are conducted with COMSOL Multiphysics. Roughness is modeled as triangular obstructions on one of the plates ...

Citation Formats

M. Alipour, “Modeling of fluid -vapor interface in the condensation zone of a grooved heat pipe,” M.S. - Master of Science, Middle East Technical University, 2017.