EnginSoft - Conference Abstracts

EnginSoft International Conference 2010
CAE Technologies for Industry

Multi scale approach for walking hearth reheating furnaces simulation

Battaglia Valerio - Centro Sviluppo Materiali (Italy)
Fantuzzi Massimiliano - Tenova LOI Impianti (Italy)
Malfa Enrico - Centro Sviluppo Materiali (Italy)
Filippini Eric - Feralpi Siderurgica (Italy)

Abstract

The paper describes the modelling approach and application to the simulation of complete furnace (Feralpi reheating furnace LAM2) including case set up and validation by comparison between calculated and measured heating curve. The furnace is equipped with 72 roof burners, and a preheating tunnel separated by a baffle. The handling system is walking heart type. The boundary condition setting take into account real wall thickness and materials, localised heat losses (charging port and the roll way).

The main problems approached to set up the comprehensive furnace model have been:

• The dimension of the computational domain. Taking into account that the main part of the grid cells (70%) are concentrated in the burners region where very high temperature, velocity and species concentration gradients request high grid resolution a procedure has been developed to drastically reduce the number of cells.
  Modelling of the steel charge. In principal the heating of charge (billet, bloom, tubes) requires unsteady calculation due to the advancement of the product inside the furnace and this requires very high computation time. The model implemented by CSM iteratively performs the coupling between the stationary simulation of the fluid dynamic inside the furnace and the non stationary simulation of the charge during its advancement in the furnace.

With proposed approach the CPU time required for the simulation of complete furnace has been strongly reduced: the simulation presented has required one week of run time using two quad core machines connected in cluster (8 processor).
The furnace simulation results allow to analysis the fluid dynamic of the flue gas, flames interaction, control zones wall temperature distribution, tunnel wall temperature, heat flux on the steel charge and evaluate furnace heat balance. In particular the heat flux in the baffle region gives reason to billets rotation of 270° due to strong deformation observed during furnace operation. The rotation has been reproduced by the steel charge model and the resulting billet heating curve shows high accuracy in prediction of the experimental heating curve.