Simulação da secagem de café utilizando a fluidodinâmica computacional

Abstract

Drying is a step in the processing of the coffee needed to maintain its quality and also for post-harvest storage, it is notable for influencing important issues such as quality. The determination of the distribution of the moisture content inside a natural coffee fruit during and at the end of the drying process is the central point in this work, for which, simulations were carried out using the finite element technique using computational fluid dynamics. Experimental data on fruit drying were carried out at a temperature (T) of 40 ° C and relative humidity (RH) of 25% to compare the results of the experiment with the results of the simulations. The fruits were dried until reaching 15.24% (b.u) of water content. Ten mathematic drying models were adjusted to the data collected. The Exponential Model of Two Terms was the one that best fit the data presenting good statistical parameterization. The data resulting from the computational fluid dynamics simulation were adjusted to the experimental drying data. The fit of the experimental data to the simulated ones was satisfactory, and in this way, the model can be used for other applications that need to represent such phenomenon. The effective diffusivity coefficient (Deff) was adjusted to the computational model in the value of 2.87 x 10-11 m2 s-1. At the end of drying, the computational model presented 57.1% of the projection area of the natural coffee fruit with moisture content below 15.3% (b.u.).