Investigation of air bubble motion in water through a vertical narrow rectangular channel by using image processing techniques

Download

index.pdf

Date

2005

Author

Özdemir, Sancak

Metadata

Show full item record

Item Usage Stats

49
views

32
downloads

This thesis presents the study of air bubble motion in stagnant water and in upward flowing water through a vertical narrow rectangular channel of 2.1X66.5 mm cross section by using image processing and analyzing techniques. The investigated bubble size range is 2 - 70 mm in area equivalent bubble diameter and mean water flow velocity is 0-25 cm/s. This study focuses on the quantitative assessment of bubble size (perimeter, area, volume, width and height), shape, path and rising velocity. The observed bubble shapes consist of circular, ellipse, ellipse wobbling, hat wobbling, cap-hat, cap and cap-bullet types. Ellipse wobbling and hat wobbling type bubble region show transition from ellipsoidal to circular cap region. The results of the ellipse bubble tests were compared with the rise velocity correlation of ellipsoidal bubbles in infinite medium and an empirical correlation for two dimensional ellipse bubbles was obtained. The cap bubble rise velocities measured in this study were compared with the correlations in literature and a new empirical correlation which is different from those given in the literature was obtained from the experimental results of this study. The trends of the cap bubble deformation which is defined as bubble height to bubble width ratio, for various water streams are almost similar in behavior. Therefore, a correlation was obtained from the measured cap bubble deformation values in water stream. The experimental results show that the bubble relative velocity under co-current flow conditions for area equivalent bubble diameter to channel width ratio, ?ae<0.6 is less than that under stagnant water condition. After bubble shapes reach to the slug type (?ae ? 0.6), relative bubble velocities pass over the terminal bubble velocities in stagnant water. If the water velocity is increased further, the bubble relative velocity increases in the slug

Subject Keywords

Mechanical engineering.

URI

http://etd.lib.metu.edu.tr/upload/12606558/index.pdf
https://hdl.handle.net/11511/15750

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Analysis of single phase convective heat transfer in microchannels with variable thermal conductivity and variable viscosity Gözükara, Arif Cem; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2010) In this study simultaneously developing single phase, laminar and incompressible flow in a micro gap between parallel plates is numerically analyzed by including the effect of variation in thermal conductivity and viscosity with temperature. Variable property solutions for continuity, momentum and energy equations are performed in a coupled manner, for air as a Newtonian fluid. In these analyses the rarefaction effect, which is important for the slip flow regime, is taken into account by imposing slip veloc...
Numerical analysis of ablation process on a two dimensional external surface Aykan, Fatma Serap; Dursunkaya, Zafer; Department of Mechanical Engineering (2005) The thermal response analysis of an ablative material on a two dimensional external surface is performed. The method is applied to both rectangular and cylindrical coordinate systems, where rectangular coordinate system is used for comparison with results available in literature. The current study solves the decomposition of the material at high temperatures by using the nth order Arrhenius equation but excludes the removal of char from the surface due to mechanical erosion or phase change and considers tha...
Experimental investigation and modeling of dropwise condensation on a horizontal gold coated tube / Serdar, Orhan; Yamalı, Cemil; Department of Mechanical Engineering (2004) The phenomenon dropwise condensation on a horizontal gold coated tube is investigated by both analytical and experimental methods in this study. A computer program is prepared to calculate the dropwise condensation heat transfer rate on the horizontal gold coated tube. An experimental setup was also manufactured to measure the dropwise condensation heat transfer rate. The effects of flow rate, temperature of cooling water and also steam to wall temperature difference have been analytically investigated by u...
Effect of surface roughness in microchannels on heat transfer Turgay, Metin Bilgehan; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2008) In this study, effect of surface roughness on convective heat transfer and fluid flow in two dimensional parallel plate microchannels is analyzed by numerically. For this purpose, single-phase, developing, laminar fluid flow at steady state and in the slip flow regime is considered. The continuity, momentum, and energy equations for Newtonian fluids are solved numerically for constant wall temperature boundary condition. Slip velocity and temperature jump at wall boundaries are imposed to observe the rarefa...
Analysis of thin walled open section tapered beams using hybrid stress finite element method Akman, Mehmet Nazım; Oral, Süha; Department of Mechanical Engineering (2008) In this thesis, hybrid stress finite element is formulated for the analysis of the isotropic, thin walled, open section beams with variable cross sections. The beam element has two nodes each having seven degrees of freedom. Assumption of stress field is sufficient to determine the element stiffness matrix. Axial, flexural and torsional effects are taken into account in the analysis. The methodology can be applied both to the tapered and the uniform beams. Throughout this study, firstly element cross-sectio...

Citation Formats

S. Özdemir, “Investigation of air bubble motion in water through a vertical narrow rectangular channel by using image processing techniques,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.