The exponential growth of computing power in the last two decades opens up entirely new options for numerical simulations of the Electric Arc Furnace (EAF). Simulations can be used to analyze physical phenomena resisting direct observation or operational measurement even to this very day. This paper gives an overview of the state-of-the-art of the Computational Fluid Dynamics (CFD) simulation on the EAF as well as an outlook on future fields of application, while being well aware that by far not all phenomena and literature can be used. The paper makes no claim to exhaustiveness, especially since three subjects of simulation technology have to be excluded: Process models for furnace controlling, stress calculations, electromagnetic simulations. Thus, the focus is on the fluid-and thermo-dynamic furnace processes and on fundamental methods that can be applied to examine these processes. The basic EAF functionalities and selected fluid-dynamic simulations are presented, for example, on multiphase flow, thermal loading of refractory lining and wall panels, chemical reactions and post-combustion, oxygen injection technology, and bottom tapping.

PurposeThe purpose of this paper is to describe the development and application of a numerical model for analysis of flow boiling phenomena and heat transfer.Design/methodology/approachFor flow boiling processes, the fluid and vapour flow regimes in connection with the conjugate heat and mass transfer problem for specimen quenching through the entire boiling curve is modelled. Vaporisation and recondensation, the vapour fraction distribution and vapour movement with respect to the liquid are considered in the calculation of the two‐phase flow and heat transfer process. The derived flow boiling model is based on a mixture model and bubble crowding model approach for two‐phase flow. In addition to the conventional mixture model formulation, here special model implementations have been incorporated that describe: the vapour formation at the superheated solid‐liquid interface, the recondensation process of vapour at the subcooled vapour‐liquid interface, the mass transfer rate in the different boiling phases and the microconvection effect in the nucleate boiling phase resulting from bubble growth and detachment.FindingsThe model prediction results are compared with experimental data for quenching of a circular cylinder, showing good agreement in boiling state and heat transfer coefficient distribution. Simulation and experiments lead to a better understanding of the interaction of incident flow in the boiling state and the resulting heat transfer.Research limitations/implicationsFluid temperatures in the range of 300‐353 K and specimen wall temperatures up to 1,000 K are considered.Practical implicationsFlow boiling is an efficient heat transfer process occurring in several technical applications. Application background of the model development is in quenching of complex metallic specimen geometries in liquids subject to fast changing heat fluxes.Originality/valueA general model for the complex two‐phase boiling heat transfer at high wall temperatures and fast flow conditions that can be used in engineering applications does not yet exist. The results provide detailed information describing the non‐uniform phase change during the complete quenching process from film boiling to pure convection.

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The quenching process within the heat treatment of workpieces can be optimized by applying locally adapted quenching conditions. Locally variable heat transfer conditions at the workpiece surface are realizable by impressing and regulation of adjustable flexible flow fields on the basis of arrays for jet flow impingings on surfaces inside the quenching media. With use of these adapted jet fields it is possible to generate spatially and or timewise varying quenching conditions with high cooling intensities for a systematic locally heat transfer during the quenching process.For the analysis of workpiece distortion activated by heat treatment, the heat transfer and hardening process by quenching in adapted flexible flow fields is modelwise described. By controlled quenching with liquid media, the quenching intensities can be increased for specific local hardening results on massive workpieces. By that, the heat treatment process and the quenching result can be affected and optimized by controlling the boiling process and the establishing of the rewetting front on the workpiece surface.Key words: distortion, distortion compensation, distortion engineering, jet quenching, impinging jet

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The distortion behaviour of a workpiece within the heat treatment process can be controlled by applying inhomogeneous quenching conditions. Locally variable heat transfer conditions at the workpiece surface within the quenching process are realizable by impressing and regulation of adjustable (spatially and/or timewise varying) flexible flow fields on the basis of jet arrays inside the quenching media. With the use of these adapted jet fields it is possible to generate various asymmetric quenching conditions for the heat treatment process. The asymmetric jet quenching process of workpieces originally has been developed in gaseous flow. By controlled quenching in liquid media like water or hardening oil and by means of jet or spray cooling with these media, the heat transfer process can be heavily increased thereby controlling the non-available boiling process and the establishing of the rewetting front on the workpiece surface. This e.g. can be realized by the use of impinging jet cooling by means of a flexible array of liquid jets.

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