Development of a numerical model for the fluid dynamic simulation of an ascending flow ripening chamber

摘要

Nowadays, the industrial seasoning of dry sausages is usually carried out in forced flow ripening chambers. In these industrial plants, air flows are preset and strictly controlled both from a fluid dynamic and a thermodynamic point of view, in order to maximize the efficiency and the productivity of the ripening stage. In this paper a parametric model aimed at the fluid dynamic simulation of ascending flow ripening chambers is presented. The main distinctive traits of this model have to be sought in the operational flexibility as well as in the ability to satisfactorily simulate the air flows inside the chamber as a function of its operational conditions, rather than in the absolute fluid dynamic accuracy of the air flow patterns. In fact the model has not been conceived as a stand alone application but as an engine for a subsequent dynamic ripening simulator software, which will be able to predict the final characteristics of ripened sausages as a function of the ripening program scheduled. This simulation software would be of great use in supporting the design phase as well as the operational phase of these kind of chambers. The fluid dynamic model presented in the paper uses the geometrical and the fluid dynamic data characterizing the cell as input data, and produces the air flow velocity patterns inside the chamber as output data. The geometrical input data are related to the main geometrical characteristics of the cell (width, height, length, position and dimension of nozzles batteries, etc.) as well as the number, type and relative placement of the sausages undergoing ripening. The fluid dynamic input data are, on the other hand, related to the overall mass flow rate that is entering the cell and its sharing ratio between the two inlet nozzle batteries. Finally, the model outcomes are represented by the air velocity patterns (module and direction) inside the cell. The model is experimentally validated, comparing the numerical outputs of the simulations with experimental data collected in a pilot ascending flow ripening chamber. Results show a satisfactory behavior, both in terms of the general shape of air patterns inside the chamber and in terms of correspondence between measured and simulated air velocity modules.