On Improvement of Evaporator Characteristics for the Beet Pump Low-Temperature Drying

A method was developed for thermal and structural calculation of the low-temperature plant air cooler designed for drying the beet pulp. Efficiency of the air cooler operation with moisture falling on the heat exchange surface, as well as optimization of the air cooler structural layout, were evaluated. The low-temperature drying plant productivity, for which the air cooler was designed, was taken equal to 21.4 kg/s of wet beet pulp (according to the drum dryer standard nomenclature). Length of the heat exchange surface was calculated through the pipes’ pitch along the front and depth, as well as the cooling capacity, on which basis the airflow was obtained making it possible to determine the device free section and the total length of the air cooler. Using these data, it becomes possible to effectively arrange and select equipment of the required overall dimensions. Nusselt and Reynolds criteria, heat transfer coefficient to the air cooler clean surface, reduced heat transfer coefficient, efficiency coefficients of the fin and of the heat transfer with freon boiling in the pipe, conditional heat transfer coefficient, as well as the wall temperature value, specific heat flux, moisture loss on the evaporator surface, heat transfer coefficient and device aerodynamic resistance in air were calculated