scholarly journals EXPERIMENTAL STUDY OF MEAN DROPLET SIZE FROM PRESSURE SWIRL ATOMIZER

2020 ◽  
Vol 4 (6) ◽  
pp. 49-59
Author(s):  
Sherry Amedorme
Keyword(s):  
Experimental Study ◽  
Liquid Film ◽  
Drop Size ◽  
Injection Pressure ◽  
Size Distributions ◽  
Sauter Mean Diameter ◽  
Hollow Cone ◽  
Mean Diameter ◽  
Drop Size Distributions ◽  
Exit Orifice

This experimental study undertakes the measurements of droplet Sauter Mean Diameter (SMD) at different axial distances for the hollow-cone nozzle and different radial distances from the spray centreline using a laser-diffraction-based drop size analyser in order to validate atomization model. The study also investigates the influence of injection pressure and the evaluation of two exit orifice diameters on the Sauter Mean Diameter (SMD). The drop size distributions along the nozzle centreline as well as the radial drop distributions from spray centreline are also evaluated. To enhance the physics of liquid sheet instability and liquid film breakup mechanisms, visualization of liquid film breakup as a function of injection pressure was carried out. The results show that mean droplet size (SMD) increases in the axial distance on the spray centreline but decreases with an increasing injection pressure on the spray centreline. It was observed that larger sized drops occupy the spray periphery compared to those occupying the spray core. For the nozzle exit orifice diameters of 3.5 mm and 1.5 mm, the results show that the small nozzle exhibits smaller SMDs than the bigger nozzle and the break-up lengths are different for the two nozzles. The drop size distributions at radial positions showed an increase in droplet formation through the spray downstream distances and become more uniform. The visualisation of the spray was carried out using high-speed camera and it was noted that a well-defined hollow-cone spray was captured and that the spray angle increases with the injection pressure but reduces with the liquid film length.

Effect of Dispersed Phase Viscosity on Emulsification in Turbulence Flow

2013 ◽  
Vol 446-447 ◽  
pp. 571-575 ◽  
Author(s):  
Chen Wei Liu ◽  
Ming Zhong Li
Keyword(s):  
Experimental Study ◽  
Drop Size ◽  
Dispersed Phase ◽  
Drop Diameter ◽  
Volume Distribution ◽  
Size Distributions ◽  
Sauter Mean Diameter ◽  
Turbulence Flow ◽  
Mean Diameter ◽  
Drop Size Distributions

Systematic experimental study has been performed to examine the effects of dispersed phase viscosity on emulsification in turbulence flow. It is found that the volume drop size distributions widen as dispersed phase viscosity increased; at lower dispersed phase viscosity, both Sauter mean diameter and the maximum stable diameter increase with the viscosity, while at higher dispersed phase viscosity, Sauter mean diameter and the maximum stable diameter decreasing and increasing, respectively. It has also been found that linear relation between the Sauter mean diameter and the maximum stable drop diameter is still valid for the emulsions which show a bimodal volume distribution, and the proportional constant decreases as dispersed phase viscosity increases.

Fuel Leaking Analysis of Fuel Tank by Projectiles Impact with Mechanical Properties of Projectiles

2013 ◽  
Vol 644 ◽  
pp. 203-206
Author(s):  
Hai Liang Cai ◽  
Bi Feng Song ◽  
Yang Pei ◽  
Shuai Shi
Keyword(s):  
High Speed ◽  
Drop Size ◽  
Fuel Tank ◽  
Size Distributions ◽  
Sauter Mean Diameter ◽  
Fuel Droplets ◽  
High Speed Impact ◽  
Fuel Tanks ◽  
Rigid Projectile ◽  
Drop Size Distributions

For making sure the dry bay ignition and fire, it’s necessary to calculate the number and the sizes of the droplets and determine the mass flow rate of the fuel induced by high-speed impact and penetration of a rigid projectile into fuel tank. An analytical model is founded and the method for calculating the initial leaking velocity of the fuel is determined. It gives the equation for calculating the drop size distributions of fuel and the Sauter mean diameter (SMD) of droplets, through the Maximum Entropy Theory and the conservation for mass. Using the Harmon’s equation for SMD,the fuel droplets SMD can be calculated. Results shows that the initial leaking velocity of the fuel is about linearly increasing with the velocity of the projectile, the SMD of fuel droplets increases with the hole size of the fuel tank which induced by the penetration of the projectile and linearly decreases with the velocity of the projectile. The results can be used for the ignition and fire analysis of the dry bay adjacent to fuel tanks.

scholarly journals Testing the Drop-Size Distribution Based Separation of Stratiform and Convective Rain Using Radar and Disdrometer Data from a Midlatitude Coastal Region

2020 ◽  
Vol 4 (1) ◽  
pp. 13
Author(s):  
Merhala Thurai ◽  
Viswanathan Bringi ◽  
David Wolff ◽  
David Marks ◽  
Charanjit Pabla
Keyword(s):  
Drop Size ◽  
Coastal Region ◽  
Size Distributions ◽  
Weighted Mean ◽  
Convective Rain ◽  
Mean Diameter ◽  
Microphysical Processes ◽  
Drop Size Distributions ◽  
Using Data ◽  
Different Characteristics

Stratiform and convective rain are associated with different microphysical processes and generally produce drop-size distributions (DSDs) with different characteristics. A previous study, using data from a tropical coastal location found that the two rain types could be separated in the NW–Dm space, where Dm is the mass-weighted mean diameter and NW is the normalized intercept parameter. The separation method has also been tested using data and observations from a midlatitude continental location with semiarid climate, and a subtropical continental location. In this paper, we investigate the same separation technique using data and observations from a midlatitude coastal region. Three-minute DSDs from disdrometer measurements were used for the NW versus Dm based classification and were compared with simultaneous observations from an S-band polarimetric radar 38 km away from the disdrometer site. Specifically, range-height indicator (RHI) scans over the disdrometer were used for confirmation. The results showed that there was no need to modify the separation criteria from previous studies. Scattering calculations using the three-minute DSDs were used to derive retrieval equations for Nw and Dm for the S-band radar and applied to the RHI scans to identify convective and stratiform rain regions. Two events are shown as illustrative examples.

Analysis of Sauter Mean Diameter (SMD) for Fuel Sprays

2007 ◽  
Author(s):  
Badih A. Jawad ◽  
Chris H. Riedel
Keyword(s):  
Drop Size ◽  
Time Pressure ◽  
Injection Pressure ◽  
Temporal Variations ◽  
Chamber Pressure ◽  
Sauter Mean Diameter ◽  
Fuel Sprays ◽  
Fuel Density ◽  
Mean Diameter ◽  
Ambient Gas

The spray-tip penetrations and the drop sizes of intermittent fuel sprays were measured by using a modified pulsed optical spray sizer. The average spray tip speeds were determined from simultaneously recorded needle lift signals and obscuration traces. The speeds of a sequence of fuel pulses injected at ∼103 Hz were analyzed to elucidate penetration mechanisms. A correlation that relates penetration distance to time, pressure drop across the nozzle, fuel density, and ambient gas density was obtained. The temporal variations of drop size in penetrating pulses of sprays were measured. The concentration of drops were calculated by combining drop size and obscuration data. The Sauter mean diameter of penetrating fuel drops increased with an increase of the chamber pressure and decreased with an increase of the injection pressure.

Mean Drop Sizes From Fan Spray Atomizers

1989 ◽  
Vol 111 (3) ◽  
pp. 342-347 ◽  
Author(s):  
H. E. Snyder ◽  
D. W. Senser ◽  
A. H. Lefebvre
Keyword(s):  
Laser Beam ◽  
Drop Size ◽  
Good Accuracy ◽  
Injection Pressure ◽  
Size Distributions ◽  
Cross Sectional ◽  
Yield Line ◽  
Silicone Oils ◽  
Drop Size Distributions ◽  
Particle Sizer

The drop size distributions produced by two geometrically similar fan spray nozzles were measured over an injection pressure range from 1.38 to 10.34 MPa (200 to 1500 psi). The fluids employed were water, water/glycerine mixtures, silicone oils, paint, and paint solvent. These liquids were selected to provide wide ranges in liquid viscosity and surface tension. A nonintrusive Malvern 2600 particle sizer, based on the forward scattering of a 5 mW He-Ne laser beam, was used to yield line-of-sight and cross-sectional drop size distributions. The atomizer was traversed across the laser beam and drop size profiles as a function of distance from the centerline were developed. Analysis of the experimental data showed that the effects of injection pressure and liquid properties on atomization quality are described with good accuracy by the following dimensionally-correct equation. SMDdh=2.83σμL2ρAdh3ΔPL20.25+0.26σρLρAdhΔPL0.25

Drop-size distributions from pneumatic atomizers

AIChE Journal ◽  
1971 ◽  
Vol 17 (3) ◽  
pp. 575-584 ◽  
Author(s):  
K. Y. Kim ◽  
W. R. Marshall
Keyword(s):  
Drop Size ◽  
Size Distributions ◽  
Drop Size Distributions
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