Experimental and Theoretical Investigation of Droplet Dispersion in Venturi Scrubbers with Axial Liquid Injection

Abstract

Droplet dispersion in a Venturi scrubber with axial liquid injection was investigated both experimentally and theoretically. The main objective of this study was to develop a mathematical model to predict droplet dispersion in a Venturi scrubber with axial liquid injection. The effects of the Peclet number and droplet size distribution on droplet dispersion were studied using the developed model. Sampling of the droplets was carried out, isokinetically, in 16 positions at the end of the throat section. The experimental data were used to find the parameters of the developed model, such as the Peclet number. From the results of this study, it was found that the Peclet number was not constant across the cross section of the scrubber channel. In order to achieve a better agreement between the results of the model and the experimental data, it was required to consider Peclet number variations across the Venturi channel. It was also revealed that the parameter representing the width of the Rosin-Rammler distribution of droplet size could not be considered constant and it was influenced significantly by the operating parameters such as liquid flow rate and gas velocity.

CFD modeling of droplet dispersion in a Venturi scrubber

“…Some experimental and theoretical studies have shown that the exponent n RR in Rosin-Rammler function can be adjusted to make agreement between theoretical and experimental results. This explains why the different values have been reported for n RR (between 1.6 and 2.7) which were obtained in different operational conditions [11,15,21].…”

“…The degree of droplet dispersion depends on droplet diameter, liquid characteristics and the intensity of turbulence [19]. For the case of Venturi scrubber with axial liquid injection, the turbulent diffusion mechanism is solely responsible for transversal droplet dispersion [11]. Thus the accurate prediction of turbulent gas diffusivity is important in simulating droplet dispersion especially for this kind of Venturi scrubber.…”

“…were not reported in this work. Talaie et al [11] have performed a theoretical and experimental study to show that Peclet number could not be constant across the cross section of Venturi scrubber. They have concluded that for better prediction of droplet concentration distribution, the radial variation of Peclet number must be taken into account.…”

“…A modified mathematical model was introduced which differed from the earlier works of Fathikalajahi et al [7], Gonç alves et al [8] and Talaie et al [11] in applying two-dimensional velocity profile for gas and droplets based on Eulerian approach and computing gas eddy diffusivity using k-ε turbulence model. While in the previous models a constant Peclet number was used to find gas eddy diffusivity.…”