The experimental validation of a CFD model for a heating oven with natural air circulation

This paper discusses a 3-D Computational Fluid Dynamics (CFD) model and presents experimental analysis of the flow and thermal processes within a laboratory heating oven with a natural air circulation. This device is used to store laboratory samples and products at a high, constant and spatially uniform temperature. The mathematical model included heat conduction in the insulated walls and convective and radiative (between walls) heat transfer in the volume of air within the oven. To formulate the mathematical model, a number of experiments were carried out to determine the temperature boundary conditions along the U-shaped heaters and the emissivity of the internal and external walls to determine the radiative heat fluxes. In addition, to validate the spatial temperature and velocity fields in the storage chamber and on the external oven walls, a set of thermocouples and Particle Image Velocimetry (PIV) were employed. The existing device was assessed in four configurations using a certification procedure that was performed at its maximum temperature level. The device was then numerically simulated using the mathematical model developed for this study. The results show satisfactory agreement between the experimental and computational velocity and temperature values. Furthermore, this study developed potential changes for the construction of this device that will improve the temperature uniformity within the storage space.