On the formula acceptable for calculating the time of complete evaporation of both small and large spherical water droplets

Aim. The paper formulates and solves the problem of obtaining analytical formulae for calculating the evaporation time of small and large droplets of spherical shape.

Methodology. The paper relies on analytical methods of mathematical physics in solving the problem of non-stationary evaporation of droplets. Use is also made of numerical composite methods to construct a general formula for all regimes of evaporation of droplets.

Results. A unified analytical expression linking the lifetimes of both small and large spherical water droplets is obtained. The mentioned cases of large and small droplets correspond to different asymptotics. Separate formulae for calculating the evaporation time of small and large spherical aerosol droplets are found. As a result of the numerical analysis of these formulae in the non-stationary process of evaporation of water droplets, a simpler formula acceptable for calculating the lifetime of both small and large spherical water droplets is derived. Formula-built graphs of the dependence of the lifetime of the drop on its initial radius at different values of the ambient temperature are compared with those obtained by other authors.

Research implications. The paper is of great interest both for the theory of non-stationary evaporation of droplets, and for the use of the obtained results in numerous practical applications.

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