Bild © Foto: Martin Braun

The main objectives of the Department of Industrial Furnaces and Heat Engineering (Institut
für Industrieofenbau und Wärmetechnik - IOB) headed by Professor Herbert Pfeifer, are process and technical plant optimisation in the fields of manufacturing, processing and recycling of iron and steel, non-ironmetals, glass and ceramics.

Key Research Areas

A) Industrial Furnaces Technology

The working group “industrial furnaces technology” is active in the field of fluid-flow and heat transfer research concerning preheating- and annealing- furnaces. The main emphasis of the investigations is on furnaces of the aluminium and copper industry, where the heating is dominated by convection.

The main research topics are:

Increasing the energy and resource efficiency by

  • Fluid flow and heat transfer optimization
  • Innovative energy recuperation methods
  • Innovative plant concepts
  • Consideration of the energy flows (energy balances)
  • Hot gas ventilators and duct systems for high temperature applications
  • Heating methods in industrial furnaces, direct (gas fired) or indirect heating (gas fired or electrically heated radiant tube)
  • Homogenising the heat transfer conditions of parts
  • Nozzle systems for high convection furnaces

Investigations of specific furnace types

  • Process gas furnaces:
  1. Optimisation of gas exchange stategies
  2. Monitoring process gas exchanges
  3. Development of metal-oxide-sensors for process gas monitoring
  • Strip floatation furnaces: carrying capacity and stability optimization for the contact free (aerodynamic) transport of metal strips
  • Gas fired bolt preheating: improving efficiency by improving the impulse and energy exchange

Modelling special heat transfer processes

  • Modelling recrystallization and corn growth of copper materials [20]

For the research done in the industrial furnaces technology field, the following methods
are mainly used:

  • Numerical simulations of the heat and mass flow phenomena in industrial furnaces using CFD (computational fluid dynamics) software
  • Fluid-Structure-Interaction: Effect of fluid flow and heat transfer phenomena on the structure (stresses/ strains) of the parts to be heated and furnace components
  • Experimental investigations using Laser-Doppler-Anemometry (LDA), Particle-Image-Velocimetry (PIV), Laser induced Fluorescence (LIF)

B) Energy and mass balances

The working group "mass and energy balances for electric arc furnaces" is not only active in the field of process technology, but also in the fields of process optimization and development. The group is mainly concerned with setting up and analyzing mass and energy balances, especially for the electric arc furnace (EAF), but also for other energy intensive high temperature processes.

The analysis of energy flows as well as the development of process monitoring and control strategies is carried out based on many years of experience in the installation and operation of off-gas analyzing systems at industrial high temperature aggregates. This experience is complemented by the insights gained by the use of not only empirical, but also numerical modelling, using commercial CFD software. In addition, the working group operates a pilot plant scale electric arc furnace.

The main aim of the research done in this field is usually to increase the energy and resource efficiency of the process concerned. For example, in the course of a project sponsored by BMWi a model to improve the yield of chrome during an electric arc furnace process was developed and during a project supported by the EU methods to improve the control of the process of an electric arc furnace by applying an on-line off-gas analyzing system was successfully investigated. The main aim of a current project is the high-productivity and resource-efficient manufacturing of carbon-fibres for a wide range of applications.

C) High- temperature flows in metallurgical reactors

Understanding the fluid flow during continuous casting of steel, copper and aluminium and its optimisation is crucial for the quality of the semi-finished and final products. In the case of continuous casting the metallurgical reactors (ladle, tundish, molds) are very important. The chemical-physical reactions, phase changes, mixing and purging reactions of the nonmetallic particles suspended in the melt are influenced by the fluid flow. Especially nonmetallic particles have a detrimental effect on the forging characteristics and properties of the resulting material and therefore have to be removed from the melt as thoroughly as possible. Measurements in molten metal are only possible to a limited extent. As the kinematic viscosity of melts and water are almost the same and the flow characteristics are therefore similar, the fluid flow and heat transfer phenomena are investigated using physical and numerical methods. The institute has several water model- test benches of converters, ladles, tundishes, continuous casting molds, and strip casting assemblies at its disposal. For the fluid flow investigations modern laser measurement equipment such as PIV, LDA and laser light sheet techniques as well as LIF-processes are available for the measurement of temperature and concentration distributions. In addition, residence time distributions (RTD), mixing processes and purging rates can be investigated experimentally.