| Popis: |
In the heat treatment of the foodstuffs, exists one point or region in the inside of the same, known as thermic center or critical point, where microorganisms have a bigger probability of surviving. The effectiveness of the procedure depends so much of the temperature seemingly as of the necessary time to attain the lethal value required in the process. A case has to do with conduction not stationary from the point of view of the transference of heat and on this aspect; a lot of information in the technical literature appears. Two adimensional groups are present in the graphic and analytical solutions, Fourier and Biot numbers, this last depend of convection coefficient of the midway of heating or cooling that surrounds the product. To find a reliable value of this coefficient is not a simple task right now than in addition to depend on density, the thermic conductivity, viscosity and specific heat, depends on geometry and of the conditions of the external flow. A method, that by means of two relatively simple algorithms they allow estimating, presents the value of the heat transfer coefficient of heat for determined conditions of work and the temperature in the thermic center for a given time itself in this work. The calculations come true by means of a program of computation, designed and implemented for the purpose, named CAENTER. The effectiveness of the method and the advantages of the program ware corroborated themselves with different practical situations. |
