Прискорення емульсії як основний фактор гідродинамічного диспергування жирової фази молока

Abstract

Знайдено аналітичні залежності для визначення середнього діаметра жирової кульки після гідродинамічного диспергування та прискорення руху молочної емульсії, які базуються на критерії руйнування крапель Вебера, унаслідок чого прискорення здатне стати універсальним, об’єднуючим чинником руйнування жирових частинок емульсій для більшості типів гомогенізаторів (клапанних, струминних, імпульсних, роторних, відцентрових і змішувальних).

The article highlights the main obstacle to the creation of highly effective homogenizers of fat emulsions with the reduced energy consumption – the lack of a uniform theory of fine dispersed emulsions dispersion and, as a consequence, a single factor (factors) for the destruction of fat particles (droplets) of the dispersed phase. The reasons for using the universal criterion of a fatty ball deformation and destruction are shown – Weber's criterion, for determining which it is necessary to calculate the slip rate of the disperse particle in relation to the dispersion phase. Given the difficulty in determining the slip rate of fatty particles, it is proposed to use the acceleration parameter of the emulsion. With the advent of acceleration, due to the difference in density between it and the surrounding plasma, inertial forces that cause the fat droplets to move with a speed different from the dispersion medium appear. The purpose of the article is to determine the relationship between the acceleration of the milk emulsion movement and velocity of the fatty ball relative to its plasma (velocity) and Weber criterion. In order to achieve the goal, an estimated flow pattern of the emulsion with fatty ball with acceleration is drawn up. As a result of mathematical transformations, based on classical theories of kinematics and hydrodynamics, analytical dependences have been found to determine the mean diameter of the fatty ball after hydrodynamic dispersion and acceleration of the milk emulsion movement based on the criterion for the destruction of Weber drops. The obtained dependences are based on the definition of the acceleration of the emulsion movement – a parameter that is easily determined for any type of homogenizer, which can become universal – a unifying factor for the destruction of fat particles of the emulsions for most types of homogenizers (valve, jet, pulse, rotary, centrifugal, and membrane). The index – the homogenization coefficient, which binds acceleration of the emulsion movement with an average diameter of the fat fraction of the milk emulsion, which characterizes physical and mechanical properties of the emulsion, the value of which is to be specified experimentally – is introduced. A hypothesis that the coefficient of surface tension at the boundary of fatball-plasma of milk has physical content of the specific energy per unit of the surface of the fatty ball is put forward. It is similar to the surface theory of the crushing of bodies P. R. Rittinger.