Estimation of distributed heat flux parameters in localized heating processes

Abstract

In this work a numerical-experimental methodology is presented based on a combined finite element model and experimental tests, for the determination of the heat flux distribution in oxy-acetylene localized heating processes commonly employed in the shipbuilding industry. The Levenberg-Marquardt algorithm is employed in the inverse conduction heat transfer problem using the results of experimental tests in thin flat circular steel plates with different thicknesses subjected to heat flux applied over the heated area, considered constant from the beginning to the end of heating, on the centre of the plates, followed by natural cooling. The transient temperatures in different points of the plate are measured by five thermocouples, affixed opposite to the oxy-acetylene flame. Additionally, the thermal analysis is performed using a non-linear two-dimensional axisymmetric finite element model to describe the heating and cooling processes, and the calculated and measured temperatures are compared. A statistical analysis is performed to demonstrate the stability of the methodology and the reliability of the results. Average residuals from the discrete in blocks and continuous Gaussian heat flux distribution models are compared. Good agreement is achieved with the use of the inverse problem methodology.