Experimental and theoretical study of the distribution of mass concentration of solid particles in the two-phase laminar boundary layer on a flat plate

1996 ◽  
Vol 22 ◽  
pp. 123
Author(s):  
M Hussainov
1988 ◽  
Vol 186 ◽  
pp. 223-241 ◽  
Author(s):  
B. Y. Wang ◽  
I. I. Glass

The compressible laminar boundary-layer flows of a dilute gas-particle mixture over a semi-infinite flat plate are investigated analytically. The governing equations are presented in a general form where more reasonable relations for the two-phase interaction and the gas viscosity are included. The detailed flow structures of the gas and particle phases are given in three distinct regions: the large-slip region near the leading edge, the moderate-slip region and the small-slip region far downstream. The asymptotic solutions for the two limiting regions are obtained by using a series-expansion method. The finite-difference solutions along the whole length of the plate are obtained by using implicit four-point and six-point schemes. The results from these two methods are compared and very good agreement is achieved. The characteristic quantities of the boundary layer are calculated and the effects on the flow produced by the particles are discussed. It is found that in the case of laminar boundary-layer flows, the skin friction and wall heat-transfer are higher and the displacement thickness is lower than in the pure-gas case alone. The results indicate that the Stokes-interaction relation is reasonable qualitatively but not correct quantitatively and a relevant non-Stokes relation of the interaction between the two phases should be specified when the particle Reynolds number is higher than unity.


2009 ◽  
Vol 47 (6) ◽  
pp. 892-901 ◽  
Author(s):  
A. I. Kartushinsky ◽  
I. A. Krupensky ◽  
S. V. Tisler ◽  
M. T. Hussainov ◽  
I. N. Shcheglov

Author(s):  
M. Hussainov ◽  
A. Kartushinsky ◽  
E. E. Michaelides ◽  
Y. Rudi ◽  
I. Shcheglov ◽  
...  

A method for the assessment of the deposition of fine solid particles in a vertical two-phase laminar flat-plate boundary layer is presented. The method is based on a probabilistic approach to the particles deposition and takes into account both the hydrodynamics of the flow past the plate and the adhesive properties of particles and the plate surface. Electrocorundum powders with particle sizes of 12, 23 and 32 μm were used for the investigations. A stainless steel hollow conical shape was used as a prototype surface for the particles deposition. The experimental investigation used the centrifugal technique for the deposition of particles and examined pairs of particles and surfaces for the characteristics of the deposition process. The results exhibited the typical log-normal distributions of the dependence of the deposition/adhesion process. An overall expression for the particles deposition flux was derived. The expression includes the normal to the surface velocity of the particles, the particle mass concentration observed immediately close to the surface of the plate and the surface of the plate. The hydrodynamic properties of the dispersed phase in the vicinity of the plate surface, namely the normal velocity and the particle mass concentration, were calculated by the mathematical model of the flat-plate laminar boundary layer elaborated in [1]. The validation of the proposed method of assessment of deposition was accomplished by comparing the deposition flux calculated along the plate with experimental data obtained in [2]. A small discrepancy between the numerical and experimental results was observed, which may be attributed to neglecting the microphysics of adhesion, such as the influence of the electric charges and humidity during the experiments.


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