3-D numerical simulation and analysis of heat transfer, fluid flow and solidification inside the mould during continuous casting of steel

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.A Three Dimensional simulation of mould in continuous casting process with consideration of standard k-& model has been presented and corroborated. The main difference between this work and previous ones is that the phase change process (solidification) and turbulent flow distribution have been coupled and solved jointly instead of dividing it into ''transient heat conduction process" and "steady fluid flow" that can lead to more realistic simulation. The main objective in this work is to have better understanding of the fluid flow pattern, heat transfer and solidification in the continuous casting mould Investigating the influence of superheating degree, nozzle port angle, casting speed, comparing the temperature distribution and analyzing other parameters, can lead us to a better design in the way of optimistic working condition.ej201

Boundary Condition Estimation of Ablating Material Using Modified Sequential Function Specification Method

International audienceAn inverse analysis is applied in a one-dimensional ablation problem for simultaneous estimation of unknown time-dependent boundary conditions including the applied heat flux and the Biot number at the two end surfaces of the ablating material. The sequential function specification method is employed to minimize the least-square objective function. Due to the ablation process, a moving boundary is created at the heated surface. The estimated boundary conditions along with the direct equations are used to calculate the front position of the moving surface. To deal with the high nonlinearity caused by the moving boundary and to treat the ill posedness associated with deeply embedded sensors of the current inverse problem, a small number of future time steps are used as the regularizing parameters to stabilize the inverse problem. Furthermore, to fasten the solution of the inverse problem, a new adaptive overrelaxation factor is developed that increases the speed of convergence significantly. The simulated temperature measurements at specific sensor positions inside the ablating materials are used to evaluate the objective function. The accuracy of an applied inverse analysis is examined by the step and triangular boundary condition profiles containing discontinuities and sharp corners, respectively. In spite of high nonlinearity, an appropriate consistency between the estimated values and the exact ones are obtained

Estimation of applied heat flux at the surface of ablating materials by using sequential function specification method

International audienceThis paper presents an inverse analysis in one-dimensional ablation problem with the presence of a moving boundary to estimate the unknown applied heat flux at the surface of ablating materials. The estimated heat flux was used to obtain the location of moving front surface. The Sequential function specification method (SFSM) was implemented to minimize the least square objective function. Simulated temperature measurements at specific sensor positions inside the ablating materials were used in the inverse analysis. Due to the ill-posedness of the problem the number of future time steps was used as the regularizing parameter. We show that only a small number of future time steps is required to deal with the great nonlinearity of an inverse problem. The accuracy of applied inverse analysis was examined by functions containing sharp corners and discontinuities. Despite high nonlinearity, good estimations were obtained