Numerical Simulation of Thermal Flow Characteristics in Plasma Reactor for Rotten Citrus Fruits Drying

Abstract

Rotten citrus fruits, which spread odor gas during shipping season, pose a severe problem in Jeju Island, Republic of Korea. The existing methods for food waste management such as composting using electro-drying and microorganisms have a high electricity cost and require a precise temperature control, respectively. Herein, we conducted a basic numerical study on a plasma reactor using microwave plasma and liquefied petroleum gas as a combined heat source for drying and composting rotten citrus fruits. To determine the design and operating conditions of the plasma reactor, the thermal flow characteristics inside the reactor were analyzed using a computational fluid dynamics code in ANSYS-fluent. In particular, the temperature distribution in the plasma reactor was simulated at different air flow rates of the centrifugal fan. The numerical simulation accuracy was evaluated by comparing the numerical results and actual experimental data. The temperature of the reactor decreased with the increase in the air flow rate of the centrifugal fan. Above 10 m/s, the temperature of the drying chamber and the exhaust gas remained almost constant at 507 K. In the present work, the calculated temperature shows a difference 1.13 % from the measured temperature at the combustion chamber.