Containment Fire Simulation by a CFD Code

In the frame of an international collaborative project to evaluate fire models a code benchmark was initiated to better quantify the strengths and weaknesses of the codes involved. CFX has been applied to simulate selected cases of both parts of the benchmark. These simulations are presented and discussed in this paper. In the first part of the benchmark a pool fire just represented by a heat release table is considered. Consequently, the physical fire model within CFX is simple. Radiative heat exchange together with turbulent mixing are involved. Two cases with and without venting of the fire room are compared. The second part of the benchmark requires a more detailed fire model in order to inspect the availability of oxygen locally and to control the fire intensity. Under unvented conditions oxygen starvation is encountered and the fire oscillates. Mechanical ventilation changes this behavior and provides enough oxygen all over the simulation time. The predefined damage criteria to characterize, if a target cable in the fire room would be damaged, are not met. However, surface temperatures predicted are well above the assumed threshold temperatures. A continuation of the work presented is foreseen and will address a more complex physical modeling of relevant fire scanarios.