Abstract
A study of thermal fluxes transferred during the HEATCOOL process is proposed. The concept of this process, specially designed to enhance the residual stresses relaxation, consists in the use of a consecutive three-step procedure during the coating elaboration (heating / spraying / cooling). The present study focuses on thermal exchanges occurring during the heating step. For this, the elaborated experimental equipment incorporates a series of ten holes aligned equidistantly with 5 mm separation. A burning gas mixture (premixed acetylene and oxygen) is injected through these holes and the burning gas jets impinge and heat the substrate. The stand-off distance between the heating device and the substrate may be adjusted between 30 and 90 millimeters. Concerning thermal fluxes transferred using this experimental device, a front work piece incorporating several thermocouples was used to perform heat flux measurements. In a first step, the case of a single hole was considered. Since this method is not able to provide the thermal flux directly, the corresponding thermal fluxes were deduced using an inverse heat conduction problem method that was specially developed. Results obtained using this inverse problem method based on experimental measurements are then compared with numerical predictions obtained using a computational fluid dynamic model representing the system. For this part, the PHOENICS software was used to perform the corresponding computations.
