Dynamics of interphase interaction between components during mixing

The processes of mixing, whipping, and foaming are essentially uniform and consist in dispersing the gas in a liquid. When mixing and whipping, the mixture of components is swollen due to the mechanical action; increased in volume water-insoluble protein substances (gluten proteins) form a three-dimensional spongy mesh continuous structure. It is called a gluten frame. It determines the elastic and resilient properties of the medium. Therefore, the purpose of the study is to establish the relationship between the gas holding capacity of the medium and the energy expended on the hydration of the components. The study solves the task of determining the gas holding capacity of the medium with variable parameters of the height of the liquid phase from the mixing intensity, the duration of transient processes for the formation of the full volume of the gas-liquid medium, the duration of the transient process for the dispersed gas phase yield. The difference between the levels before the gas phase formation and during the mixing (aeration) mode determines the value of the gas holding capacity. In this context, we concluded that it is expedient to completely destabilize the established modes by changing the operating modes in the working body in the flow system. An additional effect on the system is the change of hydrodynamic regimes due to the unstable dynamics of the dispersed gas phase formation. The generation of the dispersed gas phase means the presence of energy expenditure on the interphase layer formation, which should be considered in the total energy balance. At the same time, another feature should be mentioned. Part of the gas phase, which existed and continues to exist in the new mode after mixing, enters the mode of a transient process. Therefore, the most effective mixing occurs while adhering to the shifted mode for dosing components in a suspended state and the mechanical impact of the working body. Based on the given objectives and conditions of sponge dough mixing, we determined the requirements for the mixer design and found that the supply of components should last at least 45 seconds. During this period, hydration occurs and energy consumption is declining.

An alternative approach to evaluate fuel/air mixing quality

ABSTRACT A practical method to evaluate quantitatively the uniformity of fuel/air mixing is essential for research and development of advanced low-emission combustion systems. Typically, this is characterised by measuring an unmixedness parameter or a uniformity index. An alternative approach, based on the fuel/air equivalence ratio distribution, is proposed and demonstrated in a simple methane/air venturi mixer. This approach has two main advantages: it is correlated with the fuel/air mixture combustion temperature, and the maximum temperature variation caused by fuel/air non-uniformity can be estimated. Because of these, it can be used as a criterion to check fuel/air mixing quality, or as a target for fuel/air mixer design with acceptable maximum temperature variation. For the situations where the fuel/air distribution non-uniqueness issue becomes important for fuel/air mixing check or mixer design, an additional statistical supplementary criterion should also be used.

DESIGNING A MIXER OF PROTEIN, MINERAL AND VITAMIN ADDITIVES

To ensure the eff ective use of protein-mineral-vitamin supplements in the diets of dairy cows, a mixer design has been developed for their preliminary mixing before adding to the main mixing process. Based on the structural-morphological analysis, alternative structural elements of the mixer design have been considered and conventional symbols were assigned to them. A morphological matrix of solutions has been compiled to off er a set of alternative options. The mixer drive was chosen by the ability to ensure high speed, rotational speed control, user-friendly operation and cost. The design uses an electromechanical drive combined with a V-belt drive. This solution meets all the specifi ed requirements and allows protecting the drive from possible overloads. The working tool was chosen based on the requirement to contact the material actively throughout the chamber volume and to avoid the formation of stagnant zones. A blade mixer with variable blade positioning was found the most eff ective tool for the high-speed mixing of bulk materials. The designed mixer will be operating at a continuously varying speed in the range from 500 to 1500 min-1. This will off er the advantages of high-speed mixing while reducing the infl uence of negative factors on the fi nal mixture quality. The resulting decision matrix will allow determining the most promising areas for further designing, which makes it possible to improve the quality of the developed technical means.

Development and research of centrifugal mixer for baby food

The study was carried out on two mixers of different designs: basic and developed. To evaluate and analyze the finished mixture, the method of high performance liquid chromatography was used. Taurine was used as a key component. The paper describes how the rational parameters of the mixer were selected, according to which recipes the mixture was prepared, and also how the final assessment of the effectiveness of the mixing equipment was carried out. The mixtures were prepared on the equipment according to three recipes. According to the first recipe, 81 experiments were carried out, with various parameters of the mixer operation, which helped to determine their rational value. For two different mixers, they turned out to be identical, so further mixing took place with the same parameters. Based on the data obtained, graphs of dependences were built, which clearly demonstrated the difference in the obtained values of the coefficient of heterogeneity. And they made it possible to judge the influence of each individual parameter. The developed mixer design showed a lower coefficient of heterogeneity in comparison with the base one. It did not exceed 10%, unlike the latter.