On the evolution of a multicomponent droplet during nonisothermal diffusion growth or evaporation

Abstract

A set of equations has been derived for the size, composition, and temperature of a multicompo nent droplet of a nonideal solution during its diffusion nonisothermal condensation growth or evaporation in a multicomponent mixture of vapors with an incondensable carrier gas. In addition to complete equations for material and heat transfer in the vapor-gas medium surrounding the droplet, the derived set, in the general case, describes the nonstationary growth or evaporation of the droplet under arbitrary initial conditions (ini tial size and temperature of the droplet and the concentrations of the nonideal multicomponent solution in it) and the establishment of the stationary values of the composition, temperature, and the rate of variations in the size of the droplet with allowance for heat effects and diffusion and thermodiffusion material transfer, Stefan flux, motion of the droplet surface, and the nonideality of the solution in the droplet. A simplified set of equations obtained without taking into account the contributions from the flow, cross effects, and thermal expansion in the equations of the material and heat transfer in the vapor gas medium has been considered. Equations describing growth/evaporation in the stationary regime have been analyzed for droplets of ideal multicomponent solutions.

Binary liquid film condensation from water-ammonia vapors mixture flowing downward along a parallel plate condenser

“…The mixture vapors condensation is found in many industrial applications such as condenser, condensing devices, air-conditioning, refrigeration technology, absorber/ generator heat exchange, nuclear technology and separation processes. The studies concern the case of mixture condensation are presented in (Akiyama et al, 2001;Kuchma et al, 2011;Kuchma et al, 2013;Zheng et al, 2019;Wang et al, 2020;George et al, 2022;Hughes and Chen, 2022). Akiyama et al (2001) presented a numerical simulation of the water-ethanol condensation on a horizontal wall in a plane two-dimensional field.…”

“…Kuchma et al (2011) studied the droplet composition and the droplet size as functions of time at small deviations from the stationary concentration in the growing droplet. (Kuchma et al (2013) considered the transient stage of evolution in size, temperature and composition of a droplet, which non isothermaly condenses or evaporates in the diffusion or free-molecular regime in the atmosphere of two condensable vapors and neutral carrier gas. George et al (2022) showed that the efficiency of heat transfer in DWC depends on the heat transfer rates of individual droplets and the droplet size distribution.…”

Modelling and Optimization of a Small Diesel Burner for Mobile Applications

“…A higher kinematic viscosity suppresses the shear-layer instabilities, responsible for the break-up of the liquid fuel into droplets in the spray [30]. Other important properties are the chemical composition of the fuel, directly affecting the diffusion of fuel molecules after evaporation and the chemical kinetics of the combustion [31], and the heating value, possibly reducing the flame temperature [32]. In simulations of a dual blend of iso-octane and n-heptane, Wu et al [33] showed that at high co-flow temperature, a difference in time of ignition occurs, with iso-octane igniting before n-heptane, mainly determined by different vaporisation and diffusion rates.…”

Evolution of size and composition of a multicomponent gas bubble in liquid solution

“…Recently, we have formulated and analyzed a set of equations for the size, composition and temperature of a droplet consisting of a binary or multicomponent solution, which non-isothermally condenses or evaporates under a quasi-steady-state diffusion regime in a multicomponent mixture of vapors and non-condensable carrier gas [18][19][20][21][22]. Some of these equations have been analytically solved.…”