This paper outlines the main results obtained within the scope of joint project activities concerning the numerical simulation of reacting flow in complex geometries. The aim is the refinement of numerical methods for applied computational fluid dynamics (CFD) using high-performance computations (HPC) to study explosion processes in more detail, especially for hydrogen safety in technical systems. The R&D work is mainly focused on the modeling of the accident-related behaviour of hydrogen in safety enclosures ranging from slow to fast or even rapid flames. Therefore, we have established a modern field code cluster with supercomputing and special modules for specific studies. This methodology allows the assessment of adequate safety measures to control deflagration-to-detonation transition (DDT) processes and to suppress fires or explosions for industrial safety. (C) 2002 Elsevier Science B.V. All rights reserved.