Верифікація моделей динаміки масообмінних процесів в апаратах з вільною міжфазною границею сучасних технологій очищення повітря

The application of physical and mathematical modeling methods allows for a deeper understanding of mass transfer processes and optimize the operation of air purification technological equipment. One of the promising directions for purifying atmospheric air from harmful gaseous and dispersed impurities is the use of devices with a free interphase boundary, which allow for the maximum area of phase contact and ensure intensive mass exchange between the gas and liquid phases. Depending on the type of contamination, mass transfer can occur in dispersed and continuous phases, which by their nature can be homogeneous or heterogeneous with features of fractal objects. Research objective: verification of physical models of mass transfer process mechanisms in technological devices with a free interfacial boundary, designed to purify polluted air from harmful gaseous and dispersed components, taking into account the heterogeneity and fractal features of possible research objects. An example of such objects is cloudy air in the form of fog from finely dispersed droplets of condensed ammonia or sulfuric or nitric acid, during the purification of which heat exchange and hydrodynamic processes occur. Physical models of the absorption gas purification process are formulated and presented, taking into account changes in gas concentration along the height of the absorption apparatus. In accordance with the proposed physical models, mathematical models of differential equations of mass transfer have been developed, which require the use of a rectangular Cartesian coordinate system or a cylindrical coordinate system. The basis of the numerical model is the equation of convective diffusion. Temperature changes can significantly affect (heating during gas dissolution) the quality of gas purification. One way to counteract these phenomena is to cool the absorption apparatus by natural convection by increasing its external surface, possibly by reducing its diameter. At the same air flow rate and flow velocity, the reduction in the diameter of the device should correspond to an increase in the number of parallel-connected similar sections ("plates"). The layout of these sections becomes a combination of series and parallel connections of single absorption elements. The considered fractal model of diffusion in a dispersed system of particles or droplets in polluted air allows us to describe different modes of the transport process from normal diffusion to superdiffusion (almost channeling) using a single structural parameter. It is shown that verification of simple physical models allows one to predict, by comparing mass transfer rates with the velocities of air and absorbent flows, what mass transfer regime can be expected. Simple relationships and dependencies, obtained by this method entirely analytically, made it possible to quickly assess regulating physical factors, modes of physical processes, and calculate the design parameters of air purification devices.