Research Article Experimental and Theoretical Investigation of Droplet Dispersion in Venturi Scrubbers with Axial Liquid Injection Droplet dispersion in a Venturi scrubber with axial liquid injection was investi- gated 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. Keywords: Droplet size distribution, Liquid dispersion, Mathematical modeling, Peclet number, Venturi scrubber Received: July 09, 2008; revised: December 13, 2008; accepted: January 24, 2009 DOI: 10.1002/ceat.200800327 1 Introduction Development of highly efficient equipment for removal of pol- lutants from stack gas streams has attracted a great amount of attention as a result of new stringent environmental regula- tions. One of the equipments used for this removal is the Ven- turi scrubber. It is a simple, compact, and highly efficient gas- cleaning device which can be employed to remove particulate and gaseous pollutants from stack gas before release into the atmosphere. Liquids are used in this kind of scrubbers to wash away the pollutants. The liquid is normally injected through a nozzle and atomized to form many tiny droplets. The main issue in this process is non-uniform dispersion of the droplets formed. The importance of droplet concentration distribution in the performance of Venturi scrubbers has been recognized by several researchers [1–6]. In order to obtain good perfor- mance from Venturi scrubbers, the distribution of droplet con- centration should be very uniformly set by adjusting operating parameters. Thus, the accurate prediction of droplet concen- tration distribution is very important for optimizing Venturi scrubber performance. The trajectory of the penetrated jet, liquid break-up rate, droplet size distribution, turbulence in- tensity, and gas velocity are the main factors affecting droplet concentration distribution. Taheri and Hains [1] have performed pioneering studies of the droplet concentration distribution in a Venturi scrubber. They showed the importance of uniformity of droplet disper- sion in the performance of Venturi scrubbers. Taheri and Sheih [2] have used a two-dimensional dispersion model to predict the droplet concentration distribution in a Venturi scrubber with vertical injection. They have assumed that droplets are generated along a transverse line source. Viswanathan et al. [3] have improved the above model by considering multiple point sources for droplet generation. Fathikalajahi et al. [4] have modified the work by using a three-dimensional dispersion model to calculate droplet dispersion in a Venturi scrubber. They have also introduced a new approach to calculate the eddy diffusion coefficient of droplets. Goncalves et al. [5] have © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim http://www.cet-journal.com Mohammad Reza Talaie 1,2 Nader Mokhtarian 1 Amir Reza Talaei 1 Mehdi Karimikhosroabadi 1 Farhad Sadeghi 2 1 Islamic Azad University, Shahreza Branch, Shahreza, Iran. 2 Chemical Engineering Department, University of Isfahan, Isfahan, Iran. – Correspondence: Prof. M. R. Talaie (mrtalaie@eng.ui.ac.ir), Islamic Azad University, Shahreza Branch, Shahreza, Iran, and Chemical Engineering Department, University of Isfahan, Isfahan, Iran. 798 Chem. Eng. Technol. 2009, 32, No. 5, 798–804