scholarly journals Experimental Study on Atomization of Plain Jet Injector Under High Pressure Co-Axial Air Flow

1987 ◽  
Author(s):  
Gui Xiang Yang ◽  
J. S. Chin
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
Drop Size ◽  
Air Flow ◽  
Test Chamber ◽  
Back Pressure ◽  
Air Pressure ◽  
Working Fluid ◽  
Air Velocity ◽  
Pressure Drops

An experimental study has been conducted on the effect of high back pressure on the spray characteristics of a plain jet injector under coaxial high velocity air flow. The air pressures tested range from 1 to 16 atm, the range of air velocity is 60–120 m/s, the pressure drops of injector tested are 200–2000 kpa. Working fluid is water. Injector hole diameter is 0.5 mm. The key feature of the experiment is using a convergent-divergent nozzle to maintain a high air pressure inthe test chamber and at the same time to maintain a high velocity air flow in the atomization zone. Such an experimental arrangement totally eliminates air and droplets recirculation in the test chamber and problem related to slow droplet settling in a commonly used pressurized vessel for high back pressure atomization research. The results show that SMD decreases monotonicly with the increase of back pressure or air velocity, at different air velocities, the effect of air pressure is different. The drop size distribution parameter N in Rosin-Rammler distribution decreases slightly with increase of back pressure or air velocity.

An Experimental Study of Liquid Entrainment by Rapid Surface Swelling of Two-Phase Mixture in a Vessel

2001 ◽  
Author(s):  
Moon-Hyun Chun ◽  
Kyong-Won Seo ◽  
Hyeng-Kuk Kim
Keyword(s):  
Experimental Study ◽  
Water Level ◽  
Air Flow ◽  
Water Levels ◽  
Working Fluid ◽  
Entrainment Rate ◽  
Two Phase ◽  
Initial Water ◽  
Liquid Entrainment ◽  
Phase Mixture

Abstract An experimental study of liquid entrainment by rapid surface swelling of a two-phase mixture in a vessel has been performed. To investigate the effects of air flow rate and initial water level on the liquid entrainment, a series of experiments have been performed using air and water as working fluid. A total of 64 experimental liquid entrainment rate data have been obtained for various combinations of the test parameters (i.e., for six different initial water levels and various air flow rates) using two test vessels that have the same height but different inner diameters (0.15 and 0.3m, respectively) for vertical bubbly and churn-turbulent flow conditions. An empirical correlation for the liquid entrainment rate, E has been developed in terms of the superficial velocity of air, the initial water level, the density of gas, the surface tension, and the gravity. This correlation shows a good agreement with the present experimental data within ±30% over a wide range of flow parameters.

Spray Characteristics of Plain-Jet Airblast Atomizers

1984 ◽  
Vol 106 (3) ◽  
pp. 634-638 ◽  
Author(s):  
N. K. Rizk ◽  
A. H. Lefebvre
Keyword(s):  
Drop Size ◽  
Air Pressure ◽  
Liquid Viscosity ◽  
Liquid Ratio ◽  
Air Velocity ◽  
Spray Characteristics ◽  
Test Range ◽  
Scattering Technique ◽  
The Mean ◽  
Light Scattering Technique

The effects of air and liquid properties and atomizer dimensions on the spray characteristics of plain-jet airblast atomizers are examined. Mean drop size and drop-size distribution are measured using an improved form of light scattering technique. The test range includes wide variations in air velocity, air pressure, air/liquid ratio, and liquid viscosity. The experimental data generally confirm the results of previous studies on prefilming types of airblast atomizers. They show that increases in air velocity, air pressure, and air/liquid ratio all tend to produce a more uniform spray and a lower mean drop size. It is also observed that any change in air properties, liquid properties, and atomizer geometry that lowers the mean drop size also produces a more uniform distribution of drop sizes in the spray.

scholarly journals Theoretical and experimental study of the influence of temperature, humidity and density on the processes of drying, cleaning and filtration of cotton raw materials

2021 ◽  
Vol 1 (4) ◽  
pp. 8-15
Author(s):  
Sirojiddin Fayziev ◽  
Nafisa To’raeva ◽  
Sitora Fatullayeva
Keyword(s):  
Experimental Study ◽  
Raw Materials ◽  
Air Flow ◽  
Moisture Loss ◽  
Air Velocity ◽  
Influence Of Temperature ◽  
Loss Process ◽  
Existing Problems ◽  
Different Temperatures ◽  
Laboratory Device

The article presents information about existing problems and their solutions in the process of drying cotton raw materials at cotton gin plants, patterns of changes in the humidity of cotton raw materials at different values of the warm air velocity are obtained. The influence of the density of cotton raw materials and the relative air velocity on the change in the moisture loss coefficient at different temperatures of the air flow was investigated and it was established using a laboratory device that at a density of 0.5 g/cm3, the moisture loss process in cotton raw materials.

scholarly journals The Influence of Air and Liquid Properties on Airblast Atomization

1975 ◽  
Vol 97 (3) ◽  
pp. 316-320 ◽  
Author(s):  
A. A. Rizkalla ◽  
A. H. Lefebvre
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Surface Tension ◽  
High Velocity ◽  
Drop Size ◽  
Thin Sheet ◽  
Dimensionless Equation ◽  
First Results ◽  
Temperature And Pressure

An experimental study of airblast atomization has been conducted using a specially designed atomizer in which the liquid is first spread into a thin sheet and then exposed on both sides to high-velocity air. The first results of this study, reported in reference [1], were confined to the effects of liquid properties, namely, viscosity, surface tension, and density on atomization quality. Since then the experimental data have been extended to include the influence of air properties, notably temperature and pressure, on-mean drop size. The purpose of this paper is to present these data and to show that the effects of both air and liquid properties on atomization quality are described by the following dimensionless equation: SMD/t=A(σeρe/t)0.5(Vaρa)−1.0(1+We/Wa)+B(ηe2/σeρat)0.425(1+We/Wa)2

scholarly journals Spray Characteristics of Plain-Jet Airblast Atomizers

1983 ◽  
Author(s):  
N. K. Rizk ◽  
A. H. Lefebvre
Keyword(s):  
Drop Size ◽  
Air Pressure ◽  
Liquid Viscosity ◽  
Liquid Ratio ◽  
Air Velocity ◽  
Spray Characteristics ◽  
Test Range ◽  
Scattering Technique ◽  
The Mean ◽  
Light Scattering Technique

The effects of air and liquid properties, and atomizer dimensions, on the spray characteristics of plain-jet airblast atomizers are examined. Mean drop size and drop-size distribution are measured using an improved form of light scattering technique. The test range includes wide variations in air velocity, air pressure, air/liquid ratio, and liquid viscosity. The experimental data generally confirm the results of previous studies on prefilming types of airblast atomizers. They show that increases in air velocity, air pressure and air/liquid ratio all tend to produce a more uniform spray and a lower mean drop size. It is also observed that any change in air properties, liquid properties and atomizer geometry that lowers the mean drop size also produces a more uniform distribution of drop sizes in the spray.

Velocity Based Defrost and Frost Inhibition of Evaporator Coils of Heat Pump

2014 ◽  
Author(s):  
Kamalakkannan Muthusubramanian ◽  
Serguei V. Dessiatoun ◽  
Amir H. Shooshtari ◽  
Michael M. Ohadi
Keyword(s):  
Heat Pump ◽  
Air Flow ◽  
Working Fluid ◽  
Time Interval ◽  
Heating Cycle ◽  
Air Velocity ◽  
Frost Formation ◽  
The Past ◽  
Minute Duration ◽  
Direction Opposite

Researchers in the past have reported various methods to either retard frost formation or minimize energy expenditure during defrosting, but the methods reported in this paper is novel. Use of air flow during heating and defrosting cycles has not been studied and reported so far. The effect of using air flow during heating and defrosting cycles of heat pump were investigated experimentally. In the heating cycle, it is found that at higher air flow velocities, it is possible to retard the rate at which frost grows on the evaporator coils of the heat pump. Changing the air velocity from 0.8 m/s to 2 m/s caused a significant reduction in the frost growth rate. The ΔT of the working fluid for the 2 m/s experiment stayed at least 0.5 ∼ 1.0 °C more than the corresponding value of the 0.8 m/s experiment for the entire 90 minute duration of the heating cycle. In the defrost cycle, it is found that using air flow in the direction opposite to the normal air flow on the evaporator coil provides an energy saving opportunity by increasing the time interval between subsequent defrosting. It was seen that a reduction of 1 ∼ 2 defrost cycle was possible in 1 hour of operation, depending on the level of frost formation.

scholarly journals Energy Considerations in Twin-Fluid Atomization

1990 ◽  
Author(s):  
Arthur H. Lefebvre
Keyword(s):  
Drop Size ◽  
Sheet Thickness ◽  
Ambient Air ◽  
Liquid Sheet ◽  
Air Pressure ◽  
Air Velocity ◽  
Atomization Process ◽  
Flow Situation ◽  
Heating Oil ◽  
Main Factor

With certain types of prefilming airblast atomizers, the manner in which the atomizing air impinges on the liquid sheet prohibits the wave formation that normally precedes the breakup of a liquid sheet into drops. Instead, the liquid is shattered almost instantaneously into drops of various sizes. This prompt atomization process is characterized by a broad range of drop sizes in the spray and by a lack of sensitivity of mean drop size to variations in liquid viscosity, atomizing air pressure, and initial liquid sheet thickness. Evidence is presented to show that which of these two different modes of atomization will occur in any given flow situation is largely dependent on the angle at which the atomizing air impinges on the liquid sheet. An equation for mean drop size, derived from the assumption that the main factor controlling prompt atomization is the ratio of the energy required for atomization to the kinetic energy of the atomizing air, is shown to provide a good fit to experimental data acquired from atomization studies on water and heating oil, carried out over wide ranges of air velocity, air/liquid ratio, and ambient air pressure.

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