scholarly journals Experimental Study of the Spray Characteristics of a Research Airblast Atomizer

1985 ◽  
Author(s):  
Waldo A. Acosta
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Atmospheric Pressure ◽  
Mass Velocity ◽  
Drop Size ◽  
Unit Area ◽  
Drop Diameter ◽  
Flow Conditions ◽  
Air Mass ◽  
The Mean

An experimental study of airblast atomization was conducted using an especially designed atomizer in which the liquid first impinges on a splash plate, then is directed radially outward and is atomized by the air passing through two concentric, vaned swirlers that swirl the air in opposite directions. The effect of flow conditions, air mass velocity (mass flow rate per unit area, ρAUA) and liquid to air ratio on the mean drop size was studied. Seven different ethanol solutions were used to simulate changes in fuel physical properties. The range of atomizing air velocities was from 30 to 80 m/s. The mean drop diameter was measured at ambient temperature (295 K) and atmospheric pressure.

scholarly journals Atomization of Water Jets and Sheets in Axial and Swirling Airflows

1979 ◽  
Author(s):  
R. D. Ingebo
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Drop Size ◽  
Unit Area ◽  
Water Flow Rate ◽  
Orifice Diameter ◽  
Drop Diameter ◽  
Water Jets ◽  
Test Conditions ◽  
The Mean

Axial and swirling airflows were used to break up water jets and sheets into sprays of droplets to determine the overall effects of orifice diameter, weight flow of air, and the use of an air swirler on fineness of atomization as characterized by mean drop size. A scanning radiometer was used to determine the mean drop diameter of each spray. Swirling airflows were produced with an axial combustor, 70-deg brake angle, air swirler. Water jets were injected axially upstream, axially downstream and cross stream into the airflow. In addition, pressure atomizing fuel nozzles which produced a sheet and ligament type of breakup were investigated. Increasing the weight flow rate of air or the use of an air swiler markedly reduced the spray mean drop size. Test conditions included a water flow rate of 68.0 liter per hour and airflow rates (per unit area) of 3.7 to 25.7 g per square cm per sec, at 293 K and inlet-air static pressures of 1.01 × 105 to 1.98 × 105 N/m2.

A Comparison of Phase Doppler Analyzer (Dual-PDA) and Optical Patternator Data for Twin-Fluid and Pressure-Swirl Atomizer Sprays

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Ariel R. Muliadi ◽  
Paul E. Sojka ◽  
Yudaya R. Sivathanu ◽  
Jongmook Lim
Keyword(s):  
Drop Size ◽  
Dynamic Range ◽  
Arrival Rate ◽  
Drop Diameter ◽  
Volume Flux ◽  
Velocity Correlation ◽  
Significant Drop ◽  
Spatially Resolved ◽  
The Mean ◽  
Swirl Atomizer

The goal of this study was to determine when patternation information derived from Phase Doppler Analyzer (Dantec Dynamics, Skovlunde, Denmark, dual-PDA) measurements of volume flux, drop velocity, and mean size agreed with corresponding values measured using an optical patternator (Enurga, Inc., West Lafayette, IN, SetScan OP-600). To achieve this, data from each instrument were transformed into spatially resolved absorptances (equivalent to drop surface area per unit spray volume) and compared. Key conclusion is absorptance agreement to within 20% in many cases. However, discrepancies between phase Doppler analyzer (PDA)-calculated and optical patternator-measured absorptances become larger as the drop arrival rate increases, as the mean drop size decreases, and when a significant drop size-velocity correlation is present. These discrepancies are attributed to an underestimation of the volume flux (which becomes more important with increasing droplet arrival rate), an over-reporting of the mean drop diameter (which is the result of the restrictive data acquisition scheme applied when ensuring mass closure for the PDA measurements), the limited PDA dynamic range (which can preclude simultaneously accounting for both the largest and smallest drops in the spray), and by the optical patternator’s number-density based measurement scheme (which will not yield the same results as the flux-based PDA when a drop size-velocity correlation is present).

scholarly journals Atomizing Characteristics of Swirl Can Combustor Modules With Swirl Blast Fuel Injectors

1980 ◽  
Author(s):  
R. D. Ingebo
Keyword(s):  
Nitrogen Oxides ◽  
Water Flow ◽  
Drop Size ◽  
Unit Area ◽  
Fuel Injector ◽  
Flow Rates ◽  
Fuel Injectors ◽  
Cold Flow ◽  
Water Sprays ◽  
The Mean

Cold flow atomization tests of several different designs of swirl can combustor modules were conducted in a 7.6 cm diameter duct at airflow rates (per unit area) of 7.3 to 25.7 g/cm2 sec and water flow rates of 6.3 to 18.9 g/sec. The effect of air and water flow rates on the mean drop size of water sprays produced with the swirl blast fuel injectors were determined. Also, from these data it was possible to determine the effect of design modifications on the atomizing performance of various fuel injector and air swirler configurations. The trend in atomizing performance, as based on the mean drop size, was then compared with the trends in the production of nitrogen oxides obtained in combustion studies with the same swirl can combustors.

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.

scholarly journals Parameterization of the Sedimentation of Raindrops with Finite Maximum Diameter

2012 ◽  
Vol 140 (5) ◽  
pp. 1589-1602 ◽  
Author(s):  
Corinna Ziemer ◽  
Ulrike Wacker
Keyword(s):  
Distribution Function ◽  
Drop Size ◽  
Size Distribution Function ◽  
Cloud Microphysics ◽  
Maximum Diameter ◽  
Drop Diameter ◽  
One Dimensional ◽  
Drop Mass ◽  
Mathematical Problems ◽  
The Mean

In common cloud microphysics parameterization models, the prognostic variables are one to three moments of the drop size distribution function. They are defined as integrals of the distribution function over a drop diameter ranging from zero to infinity. Recent works (by several authors) on a one-dimensional sedimentation problem have pointed out that there are problems with those parameterization models caused by the differing average propagation speeds of the prognostic moments. In this study, the authors propose to define the moments over a finite drop diameter range of [0, Dmax], corresponding to the limitation of drop size in nature. The ratios of the average propagation speeds are thereby also reduced. In the new model, mean particle masses above a certain threshold depending on Dmax lead to mathematical problems, which are solved by a mirroring technique. An identical, one-dimensional sedimentation problem for two moments is used to analyze the sensitivity of the results to the maximum drop diameter and to compare the proposed method with recent works. It turns out that Dmax has a systematic influence on the model’s results. A small, finite maximum drop diameter leads to a better representation of the moments and the mean drop mass when compared to the detailed microphysical model.

Effects of Channel Length on Gas-Liquid Two-Phase Flow Phenomena in a Microchannel

2011 ◽  
Author(s):  
Hideo Ide ◽  
Ryuji Kimura ◽  
Masahiro Kawaji
Keyword(s):  
Void Fraction ◽  
Flow Rate ◽  
Liquid Flow ◽  
Mass Velocity ◽  
Two Phase Flow ◽  
Liquid Flow Rate ◽  
Optical Measurement ◽  
Phase Flow ◽  
Two Phase ◽  
The Mean

An optical measurement system was used to investigate the effect of microchannel length on the characteristics of adiabatic gas-liquid two-phase flow. Experiments were conducted with a 1,676 mm long, circular microchannel with an inner diameter of 100 μm. Two-phase flow patterns, void fraction and velocities of gas plug/slug and liquid slugs were measured at different locations between the gas-liquid mixer and channel exit. The experimental values of the mean void fraction and the mean velocity of liquid slug agreed well with the homogeneous flow model predictions when the liquid flow rate was constant and the mass velocity of the gas was low. The flow pattern transition from slug flow to ring film flow was observed when the mass velocity of the gas was increased while the liquid flow rate was kept constant.

scholarly journals Influence of Flow Speed on the Compression Surfaces of Inlet on Efficiency of the Boundary Layer Bleed

2019 ◽  
Vol 14 (3) ◽  
pp. 15-25
Author(s):  
M. A. Goldfeld
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Experimental Study ◽  
Flow Velocity ◽  
Hypersonic Flow ◽  
Flow Speed ◽  
Analytical Models ◽  
Flow Conditions ◽  
Air Mass ◽  
Mach Numbers

The paper presents the results of analytical and experimental study of the bleed coefficient at high flight Mach numbers from 3 to 7. For the calculation, an analytical model was used model with a fixed exit in the supercritical bleed mode, which allows varying the bleed air mass depending on flow conditions and parameter bleed system. The measurement of the bleed flow coefficients were performed for three bleed configurations in a wind tunnel at local Mach numbers in front of the bleed area from 2.5 to 5.96. The model had a long forebody, so that before the bleed area there was a thick boundary layer. As a result, new experimental data on bleed coefficient and its general dependence on the Mach numbers up to 6 and the bleed angles of 90 and 45° were obtained. It is revealed that at increase in the local Mach number, the tendency is observed towards a decrease in the bleed coefficient, and this tendency intensifies with decrease in the bleed channel inclination. These data were used to evaluate known analytical models to determine the characteristics of bleed systems at hypersonic flow velocity analytical models to determine the characteristics of bleed systems at hypersonic flow velocity.

Characteristics of a Spinning-disk Liquid Sprayer

1952 ◽  
Vol 166 (1) ◽  
pp. 443-449 ◽  
Author(s):  
W. H. Boshoff
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Drop Size ◽  
Large Diameter ◽  
Critical Flow ◽  
Drop Diameter ◽  
Uniform Size ◽  
Critical Flow Rate ◽  
Liquid Feed ◽  
Spinning Disk

In this paper is described an attempt to increase the output of a spinning-disk sprayer without sacrificing the homogeneous drop-size characteristics found by previous investigators. A disk sprayer inches in diameter was designed, and the characteristics were determined by feeding various quantities of water centrally on to the disk, and noting the resulting drop sizes and their distribution over a range of disk speeds from 600 to 2,000 r.p.m. The critical flow rate for the production of uniform-size drops is in the range 6–22 cu. cm. per sec., and the size of drops produced is inversely proportional to the speed of the disk. The product of drop diameter and peripheral velocity of the disk is approximately constant and varies with the smoothness of the surface of the disk rather than with the rate of liquid flow. Above the critical flow rate the homogeneity of the drops disappears and a wider range of sizes is observed. The distribution and sizes of the drops are independent of the rate of liquid feed over a range of from 22 to 110 cu. cm. per sec, the size of the majority of drops being dependent on the peripheral speed of the disk. Above that range the liquid comes off the disk in a sheet, in which little or no break-up of the liquid takes place. It is concluded that spinning disks of large diameter will produce drops of uniform size even at relatively low rotational speeds.

Experimental Study on Compound Swirl Jet

2003 ◽  
Author(s):  
Tsutomu Nozaki ◽  
Takashi Ochiai ◽  
Tomonari Kai
Keyword(s):  
Experimental Study ◽  
Flow Visualization ◽  
Flow Rate ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Mean Velocity ◽  
Fundamental Study ◽  
Free Jet ◽  
The Mean ◽  
Two Jets

This paper concerns the fundamental study on the push-pull type ventilator, especially applied to the smoking table. In order to achieve more effective cleaning of the dirty air, a compound swirl jet, which consists of a round free jet having thick rim and a coaxial annular swirl jet was proposed by the authors. It was found that the compound flow is very useful for the push flow of the push-pull type ventilator selecting the suitable flow rate ratio of the annular swirl jet to the free jet. As a fundamental study on the compound swirl jet, the flow visualization was also carried out using the smoke method. At the same time, the mean velocity components were measured using the cobra Pitot tube. It was found from the results of these experiments that the unique flow structure by the interaction of two jets is created in the compound swirl jet choosing the adequate flow rate ratio, which is suitable for the push flow of the push-pull type ventilator.

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