Experimental Study of Chamber Volume Effect on Bubble Formation From Orifice Plates Submerged in Water

2018 ◽  
Author(s):  
Omkar S. Gokhale ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
Bubble Formation ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Equilibrium Contact Angle ◽  
Growth Time ◽  
Size And Shape ◽  
Chamber Volume ◽  
Gas Chamber

Experimental study of air bubble formation from orifice plates submerged in water pools has been carried out. Air is forced through the orifice by supplying it to a chamber connected to the orifice plate. The chamber volume plays an important role in determining the bubble growth time as well as bubble size and shape at departure. The effect of chamber volume is generally correlated in term of a dimensionless parameter, capacitance number (Nc), which is proportional to the chamber volume and is inversely proportional to the square of the orifice diameter. To better understand and characterize this effect, an experimental study is performed using ten orifice plates of diameter ranging from 0.61 mm to 2.261 mm with six different chamber volumes between 12 cc and 59 cc with the corresponding capacitance numbers varying from 0.2 to 19. The shape and size of the bubble are captured using high speed videography. The orifice plate material is acrylic glass which has an equilibrium contact angle of 38° with pure water. It was observed that the value of critical capacitance number or Nc above which the bubble evolution is affected by the gas chamber volume, is around 0.85. The bubbles are more spherical in shape, and the growth time is significantly smaller. Also, at high capacitance number (Nc > 7), the air flow in the bubble is so high that the bubble departs with a sharp apex and has a large volume. Above Nc > 10, the chamber effects plateau and further increase in gas chamber volume does not alter bubble size and shape at departure.

scholarly journals Bubble formation in shear-thinning fluids: Laser image measurement and a novel correlation for detached volume

2017 ◽  
Vol 23 (3) ◽  
pp. 301-309
Author(s):  
Wenyuan Fan ◽  
Xiaohong Yin
Keyword(s):  
Mass Concentration ◽  
Bubble Formation ◽  
Shear Thinning ◽  
Orifice Diameter ◽  
Image System ◽  
Bubble Detachment ◽  
Chamber Volume ◽  
Shear Thinning Fluids ◽  
Gas Chamber ◽  
Thinning Effect

A laser image system has been established to quantify the characteristics of growing bubbles in quiescent shear-thinning fluids. Bubble formation mechanism was investigated by comparing the evolutions of bubble instantaneous shape, volume and surface area in two shear-thinning liquids with those in Newtonian liquid. The effects of solution mass concentration, gas chamber volume and orifice diameter on bubble detachment volume are discussed. By dimensional analysis, a single bubble volume detached within a moderate gas flowrate range was developed as a function of Reynolds number ,Re, Weber number, We, and gas chamber number, Vc, based on the orifice diameter. The results reveal that the generated bubble presents a slim shape due to the shear-thinning effect of the fluid. Bubble detachment volume increases with the solution mass concentration, gas chamber volume and orifice diameter. The results predicted by the present correlation agree better with the experimental data than the previous ones within the range of this paper.

Visual Observations of Chamber Volume Effect on Ebullience From Submerged Orifice Plates

2016 ◽  
Author(s):  
Sanjivan Manoharan ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Surface Tension ◽  
Bubble Growth ◽  
High Speed ◽  
Capillary Tube ◽  
Volume Effect ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Chamber Volume ◽  
Acrylic Glass ◽  
Liquid Pools

Effect of chamber volume upstream of the orifice on ebullience from orifice plates is studied experimentally in this paper. Bubble growth from orifice plates submerged in liquid pools is captured using high speed videography. The orifice plate substrate is acrylic glass and 11 different orifice diameters (diameter range: 0.610< D0< 2.261mm) are utilized. In addition to water, ethanol-water binary mixture with surface tension of 54 mN/m is used to examine the interplay between surface tension and chamber volume effects on bubble characteristics. For an acrylic glass orifice plate with a fixed chamber volume, above a certain transition orifice diameter, the bubbles from the orifice plate are of the same size and shape as those from a capillary tube orifice. However, below this diameter, the bubbles from the orifice plate show significantly different characteristics due to the chamber volume effect. The bubbles are more spherical in shape with the apex being sharper and more pointed. The bubbles also tend to sit closer to the plate due to their abnormally large size while the growth times are much shorter. These differences are highlighted by comparing photographs of bubble growth with and without the chamber volume effect. Additionally, for the medium chamber region, an empirical correlation was proposed to predict bubble departure diameters to within ±15 %. For a fixed chamber volume, variation in surface tension showed no change in the transition orifice diameter.

The growth and collapse of cavitation bubbles near composite surfaces

1989 ◽  
Vol 203 ◽  
pp. 199-214 ◽  
Author(s):  
A. Shima ◽  
Y. Tomita ◽  
D. C. Gibson ◽  
J. R. Blake
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
The State ◽  
Bubble Collapse ◽  
Viscoelastic Materials ◽  
Effective Parameters ◽  
Composite Surface ◽  
Surface Stiffness ◽  
Cavitation Bubbles

An experimental study has been made of the growth and collapse of a bubble near a composite surface consisting of two viscoelastic materials. The migratory characteristics of the bubble are examined by means of streak photography. The bubble migration depends not only on the properties of the composite surface but also on bubble size and distance from the surface. Both the surface stiffness and surface inertia are considered to be effective parameters contributing to the bubble migration: the former seeming to be a particularly important factor. The state of neutral bubble collapse, with no migration towards or away from a surface, can be made to occur with an appropriate combination of the surface stiffness and inertia.

Yacht Keels - An Experimental Study

1975 ◽  
Author(s):  
Pierre DeSaix
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Center Of Gravity ◽  
Full Scale ◽  
Optimum Size ◽  
Hull Form ◽  
Size And Shape ◽  
Aspect Ratios ◽  
Current Design ◽  
Lateral Area

Model tests are presented for a series of nine keels; three aspect ratios, three sweep angles; all at constant lateral area, taper ratio and thickness ratio. The series is shown to bracket current design trends. These keels are all tested on the same canoe body, over a range of heel angles, lee-ways, and speeds. The results are presented in terms of full-scale sailing performance with due allowance for a reasonable ballast ratio and resulting vertical center of gravity for each keel. Optimum sweep angles for each aspect ratio are found. A second series of three keels, geometrically similar but varying in lateral area, is provided. Predictions of windward performance demonstrate the effect of keel size. An optimum size is found for three wind strengths. The results are for one hull form only. However, a method is suggested for estimating the effect of keel size and shape for any proposed design.

Bubble Formation From Porous Plates in Liquid Cross-Flow

2018 ◽  
Author(s):  
Thomas Shepard ◽  
Eric Ruud ◽  
Henry Kinane ◽  
Deify Law ◽  
Kohl Ordahl
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Bubble Diameter ◽  
Bubble Formation ◽  
Cross Flow ◽  
Rectangular Channels ◽  
Gas Liquid Flow ◽  
Liquid Flows ◽  
Processing Techniques ◽  
The Impact

Controlling bubble diameter and bubble size distribution is important for a variety of applications and active fields of research. In this study the formation of bubbles from porous plates in a liquid cross-flow is examined experimentally. By injecting air through porous plates of various media grades (0.2 to 100) into liquid flows in rectangular channels of varying aspect ratio (1–10) and gas/liquid flow rates the impact of the various factors is presented. Image processing techniques were used to measure bubble diameters and capture their formation from the porous plates. Mean bubble diameters ranged from 0.06–1.21 mm. The present work expands upon the work of [1] and further identifies the relative importance of wall shear stress, air injector pore size and gas to liquid mass flow ratio on bubble size and size distribution.

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