Organization of the rational form of air kinetics in chamber for the heat treatment of food products

Abstract

In this work, the effectiveness of the turbulent (three-dimensional trajectory) kinetics of air in the cargo volume of thermal chambers under recirculation conditions is substantiated analytically and practical tests of heat treatment of food products by convection. The object of research is the aerodynamic parameters of the air in the zone of processing of sausage products and the temperature in their geometric center. Analytical studies of heat exchange processes were carried out on the basis of using a system of differential equations with the involvement of criterion dependencies and similarity theory, and full-scale studies were carried out on a prototype of a heat chamber with an improved air distribution system. As an experimental material, dummies of boiled sausages-sausage casings stuffed with sawdust-were used to fill the working space of the thermal chamber. In the industrial scale experiments boiled sausages "Likarska" were used. To improve air distribution, the aerodynamic network was equipped with specially designed equipment located in the upper part of the chamber symmetrically to its longitudinal axis. Uniform distribution of air along the periphery of the chamber was provided by a double-discharge centrifugal fan an air ducts of equal static pressure, heating was provided by finned bimetallic heat exchangers. Converging pyramidal nozzles on heat exchangers divided the air entering the peripheral channels of the chamber into two flat streams with adjustable aerodynamic parameters for a certain influence of each on the nature of air movement near the product. Its rational three-dimensional movement, characterized by the Reynolds criterion equal to 8200, and the product heating unevenness of 2 degrees Celsius, was formed by nozzles with geometry: air compression angle-18 degrees, proportionality coefficient of compressed air separation on the main and side flows-14, and the degree of freedom of the main flow-9.09. Thus, the implementation of technical solutions for the organization of three-dimensional air kinetics in a heat chamber under recirculation conditions ensured a sufficiently high uniformity of heat supply to processed products, their quality and safety while reducing the total cost of their production. In addition, the accuracy of engineering calculations when designing air distribution systems increased.