On the Theoretical Prediction of Fuel Droplet Size Distribution in Nonreactive Diesel Sprays

2001 ◽  
Vol 124 (1) ◽  
pp. 182-185 ◽  
Author(s):  
Jianming Cao
Keyword(s):  
Distribution Function ◽  
Size Distribution ◽  
Droplet Size ◽  
Cross Sections ◽  
Droplet Size Distribution ◽  
Size Distribution Function ◽  
Fuel Droplet ◽  
Diesel Sprays ◽  
Mean Diameter ◽  
Higher Temperature

Droplet size distribution function and mean diameter formulas are derived using information theory. The effects of fuel droplet evaporation and coalescence within combustion chamber on the droplet size are emphasized in nonreactive diesel sprays. The size distribution function expressions at various spray axial cross sections are also formulated. The computations are compared with experimental data and KIVA-II code. A good agreement is obtained between numerical and experimental results. Droplet size distribution and mean diameter at various locations from injector exit and at various temperature conditions are predicted. The decreases of droplet number and variations of mean diameter are computed at downstream and higher temperature.

The Effect of Heat Transfer Coefficient, Local Wet Bulb Temperature and Droplet Size Distribution Function on the Thermal Performance of Sprays

1977 ◽  
Vol 99 (3) ◽  
pp. 381-385 ◽  
Author(s):  
K. H. Chen ◽  
G. J. Trezek
Keyword(s):  
Heat Transfer ◽  
Distribution Function ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Size Distribution ◽  
Droplet Size ◽  
Thermal Performance ◽  
Correction Term ◽  
Droplet Size Distribution ◽  
Size Distribution Function

Energy balance considerations indicate that the droplet heat transfer coefficient, local wet bulb temperature, and droplet size distribution function are the basic parameters affecting spray system thermal performance. Within the range of available experimental data, results indicate that the Ranz-Marshall correlation gives an agreement to within ±5.0 percent of measured droplet temperatures at the pond surface for a medium wind range of between 2.5 and 5 m/s. The local wet bulb temperature is taken as the arithmetic mean of the initial and final wet bulb temperatures. For wind speeds greater than 3.5 m/s, the local wet bulb can be taken as the ambient. The modified log normal distribution of Mugele and Evans provides the best description of the droplet size distribution. Further, through the introduction of a correction term, the Spray Energy Release (SER) can be deduced from single droplet information.

scholarly journals Atomization Quality of Twin Fluid Atomizers for Gas Turbines

1982 ◽  
Author(s):  
M. M. Elkotb ◽  
M. A. Elsayed Mahdy ◽  
M. E. Montaser
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Gas Turbines ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Diameter Ratio ◽  
Air Pressure ◽  
Sauter Mean Diameter ◽  
Flow Number ◽  
Mean Diameter

A detailed investigation of the effect of nozzle/needle diameter ratio, normal fuel area, swirler degree, air pressure, fuel pressure on flow number, cone angle and droplet size distribution of external mixing twin fluid atomizers is given in this paper. Forty atomizers have been constructed to prevent mutual effect of various parameters. Flow number and cone angle are found to increase with nozzle/diameter ratio, and to decrease with the increase of air pressure. Optimum fuel flow is obtained at swirler angle 30-deg, while cone angle increases with increase of swirler angle. Sauter mean diameter decreases with the increase of air pressure and decrease of fuel pressure. Suitable functions are derived for droplet size distribution, Sauter mean diameter, and flow number. They are suitable to predict the geometry of the atomizer and to be used also in a prediction model for the calculation of fuel concentration and heat release.

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