Comportamento dinâmico de um trocador de calor de tanque agitado

Abstract

The constant technological advancement of the current era drives the optimization of various industrial processes. Thus, the study of transport phenomena is increasingly approached and deepened, since they are generally present in all industrial segments. The three transport mechanisms are: momentum transfer, heat and mass. Commonly, all three appear combined in industrial processes. In the processes of thermal exchange between two fluids, the conduction, convection and radiation mechanisms are generally taken into account, evaluating the contribution of each of these to the system. In heat exchanger analyzes, the overall heat transfer coefficient (U) and the convective heat transfer coefficient, or film coefficient (h), are evaluated. Through the global heat transfer coefficient, one can evaluate the contribution of the mechanisms involved in the heat transfer process. In addition, by determining the film coefficient, the amount of heat transferred between a surface and a fluid can be obtained, or vice versa. Thus, with these parameters one can determine the heat transfer rate. Therefore, the scientific problem of this work refers to the influence exerted on the behavior of the global heat transfer coefficient (U) and the film coefficient (h) through the operation of heat exchangers under dynamic conditions. For this, 11 experiments were performed in a jacket-stirred tank heat exchanger, considering parameters such as stirring speed and fluid temperatures. The values of global and convective heat transfer coefficients were determined and analyzed to evaluate the best conditions for conducting didactic experiments. It was concluded that the parameters of stirring velocity and inlet temperature of the hot fluid directly influence the heat losses to the medium and the heat quantity calculations.