## 1 Introduction
[PERSON] [30] and [PERSON] [31] introduced simple models that enabled the prediction of pressure drop. The assumption made by [PERSON] was that droplets accelerate. Therefore, the velocity values of the drops and the gas were finally aligned with each other at the end of the throat [30]. The model of [PERSON] [31] included the acceleration of both the gas and the droplets. The model also involved friction and presumed a liquid that was completely atomized. The model of [PERSON] et al. [32] was refined in works [33; 34; 35] where the growth and detachment of the gaseous boundary layer \((BL)\) were identified. The models of [PERSON], [PERSON] et al. are explained in [5; 16; 32]. [PERSON] and [PERSON] took into account the entrainment and deposition of the droplets, as well as the growth of the gaseous boundary layer in the diffuser area, to accurately predict the pressure drop. This model accurately explains that the increased gaseous boundary layer in the diffuser caused the excess pressure recovered from the previous models. [PERSON], [PERSON] et al. presented a one-dimensional model describing the flow of liquid, dust, and gas [5]. The two-phase flow annular pattern was also considered in the works of [PERSON] et al. [15; 36], in which the thickness of the liquid film on the wall was determined against the overall Venturi nozzle length. In addition, the velocity of the liquid film on the wall and the pressure drop were calculated under various operating conditions of Venturi. The purification process is significantly impacted by the liquid film that always forms on the walls of the scrubber [1]. When the dust exhibits particular adhesiveness or when there is an erosion in the throat, the liquid is intentionally injected as a film and then atomized by the gas. Usually, other meaningful factors are also being ignored while disregarding the existence of the liquid film on the walls of the scrubber. Since the liquid that flows as a film is not in the form of droplets, it does not have any impact on the gas purification process. The liquid film will act as a rough surface when in direct contact with the flowing gas, which will lead to an increase in pressure drop due to friction. However, the liquid film that forms along the entire length of the Venturi, which is caused by the continuous deposition of droplets on the channel wall, will lead to the re-entrainment of droplets from the liquid film. Thus, new droplets with a velocity lower than the gas velocity will be generated and utilized effectively in the gas cleaning process. Both the liquid flow as a film and as droplets are factored into the model presented by [PERSON] and [PERSON] [5]. The authors of the paper also considered the transition between the droplets and the liquid film. The paper describes a model of the annular flow, which is based on the liquid film's mass flow rate equation, which involves deposition and entrainment of droplets. This paper constitutes a continuation of previous analytical and empirical (see Appendix A) studies that addressed gas-liquid flow through the Venturi throat [1]. Gas cleaning efficiency is mostly dependent on the droplets' uniform distribution over the cross-section area of the throat. The main focus of the theoretical research carried out was to investigate the impact of the droplet deposition on the channel wall and their re-entrainment from the liquid film on the mass flow rate of the droplets in the core of the flow that varied along the throat. Experimental research (see Appendix A) was carried out to carefully study the physics of the mist flow and gradually forming a liquid film on the wall of the throat of the Venturi nozzle with a rectangular cross-section. This component of the Venturi nozzle is where the cleaning process of the gas occurs. The efficiency of gas purification can be increased by determining and improving the conditions under which the solid particles may settle on droplets easily. Identification and elimination of unfavorable factors and phenomena is crucial for this to become possible.