A preliminary assessment of using the operating head with oval nozzles for impingement fluidization of vegetables

Article history: Received: November 2014 Received in the revised form: November 2014 Accepted: December 2014 The operating system of cooling and freezing by impingement and impingement fluidization techniques was modified using oval crosssectional air jet nozzles at three different configurations of air distribution. The air jet exit velocity at different preset values of 30-50 m∙s as well as the velocity of air rebound from the operating chamber bottom were measured by applying three heads with oval nozzles and one with classical nozzles for comparative purposes. All of the nozzles had the same cross section. Freezing tests of French fries were performed in these conditions. An analysis of the rebound air velocity fields indicated that both an oval nozzle design and air velocity at the nozzle outlet determine the rebound air velocity. It was found that the limited use of oval nozzles at the impingement fluidization freezing process is possible and that 40 m∙s was the most appropriate velocity for air jets leaving the nozzles.