Numerical Investigation on Influence of Fan Speed and Swirling Gas Injection on Thermal-Flow Characteristics in Nitrocarburizing Furnace

Abstract

This study was carried out to analyze the flow and heat transfer characteristics in a furnace, and to evaluate the influence of the two major design factors for improving the flow mixing and heat transfer. The grid system was constructed using ANSYS ICEM (V. 17.0), and numerical simulations were conducted using the commercial CFD code (ANSYS Fluent V.17.0). The fan plays an important role in flow mixing and convective heat transfer in the furnace. Accordingly, temperature uniformity was improved with an increase in the fan speed owing to an enhancement of the convective heat transfer. Moreover, when swirl flow was applied to the inlet gas, temperature uniformity was improved in the lower section of the furnace. This is because the swirl flow of the inlet gas improved the flow mixing in the vicinity of the gas inlet where it is not affected by the rotational force of the fan. Controlling the swirl intensity of the inlet gas with lower fan speeds is more energy ef ficient because flow mixing and temperature uniformity could be improved sufflciently.