Study of the volume condensation process in supersaturated vapor by the direct numerical solution of the kinetic equation for the droplet size distribution function

2007 ◽  
Vol 69 (4) ◽  
pp. 450-457 ◽  
Author(s):  
N. M. Kortsenshtein ◽  
E. V. Samuilov ◽  
A. K. Yastrebov
Keyword(s):  
Distribution Function ◽  
Kinetic Equation ◽  
Numerical Solution ◽  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Size Distribution Function ◽  
Condensation Process ◽  
Direct Numerical Solution ◽  
Volume Condensation

scholarly journals INTEGRATION OF THE NUMERICAL SOLUTION MODULE OF THE KINETIC EQUATION INTO THE CFD PACKAGE FOR THE VOLUME CONDENSATION PROBLEM OF THE VAPOR-GAS MIXTURE FLOW THROUGH A NOZZLE

2021 ◽  
Vol 48 (1) ◽  
pp. 65-75
Author(s):  
A. A. Sidorov ◽  
A. K. Yastrebov
Keyword(s):  
Distribution Function ◽  
Kinetic Equation ◽  
Numerical Solution ◽  
Droplet Size Distribution ◽  
Size Distribution Function ◽  
Gas Mixture ◽  
Two Dimensional ◽  
Mixture Flow ◽  
Volume Condensation ◽  
Flow Through

Objective. Integrating the numerical solution module of the kinetic equation for the droplet size distribution function in a CFD package. Application of the module to volumetric condensation at the supersonic flow of a vapor-gas  mixture through a nozzle in a two-dimensional formulation, comparison of  the results with experimental data of third-party authors.Methods. In this  paper, the problem of volume condensation in the supersonic flow of a vapor-gas mixture through a nozzle is solved by finite element methods in a two-dimensional formulation using user-defined functions.Results. A module for the numerical solution of the kinetic equation for the droplet size distribution function is presented as a user-defined function integrated into the calculated CFD package.Conclusion. The module application to volumetric condensation for a vapor-gas mixture flow through the nozzle gave a qualitative agreement in all areas and a quantitative agreement in the area of intense condensation with  measurement data. The distributions of temperatures, pressures, and  the degree of supersaturation are presented both along the central axis and  on the plane bounded by the contour of the computational domain. It is shown that the module does not depend on the solver type (stationary or non-stationary).

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.

The New Method for Simulation of Bulk Condensation of Supersaturated Vapor

2010 ◽  
Author(s):  
N. M. Kortsenshteyn ◽  
A. K. Yastrebov
Keyword(s):  
Kinetic Equation ◽  
Droplet Size ◽  
Knudsen Number ◽  
Saturation Pressure ◽  
Droplet Size Distribution ◽  
Boltzmann Kinetic Equation ◽  
Size Distribution Function ◽  
New Method ◽  
Interphase Heat Transfer ◽  
Method Of Solution

The method of direct numerical solution of the kinetic equation for the droplet size distribution function is presented. This new method which is not restricted by the Knudsen number was developed using the analogy with a similar method of solution of the Boltzmann kinetic equation. The simulation of vapor behavior at fast creation of supersaturation state in vapor-gas mixture by means of adiabatic expansion was carried out for the verification of the method. The results obtained by this method were compared with those which were obtained by using the method of moments over a broad range of Knudsen number. The effect of the interphase heat transfer and dependence between saturation pressure and droplet size on the dynamics of condensation relaxation was studied.

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