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| Home > Publications database > Design of a test facility to investigate the turbulence of buoyancy-driven flows due to fluid-fluid-interaction |
| Poster (After Call) | FZJ-2017-06143 |
; ;
2017
Please use a persistent id in citations: http://hdl.handle.net/2128/15237
Abstract: Computational Fluid Dynamics (CFD) models are increasingly applied in fire safety science and engineering. One of the most widespread models is the Fire Dynamics Simulator (FDS). It is a model for fire-driven fluid flows (low speed, thermally driven) and is separated into different sub-models, e.g. the combustion, the radiation and the fluid dynamics models. The aim of the study is the development of a new small scale test facility which provides experimental data for the validation of the fluid dynamics model. This model determines the turbulent properties of a simulated flow, which have significant influence on the transport and the mixing processes, e.g. in a plume. The design is based on a simple setup of a heat source in an enclosure to emulate a buoyancy-driven plume. Based on FDS simulations, the geometrical extension of the enclosure is chosen to limit its boundary effects and therefore resemble open boundary conditions, as well as to quantify the impact of stratification on the plume. The enclosure is a rectangular box, where the Plexiglas walls of the box are kept at a certain temperature by suitable cooling. The heating source is positioned centrally on the floor. In previous experiments, a cubic shaped electrical heating source was used and the velocity field of the plume was captured with a particle image velocimetry (PIV) system. In case of free gas flows, turbulence arises due to shear forces (fluid-fluid-interaction). The previous experiment showed that the geometry of the heating block (flow separation at edges) has a strong influence on the turbulence intensity of the plume. Therefore, the design of the heating source has been adapted and the heating block has been lowered into the floor plate. The aim of the new test facility is to deliver a precise statement on the turbulence intensity and on fluid-fluid-interaction. To avoid disturbances of the flow, non-intrusive measurement techniques, for example particle image velocimetry (PIV) and laser Doppler velocimetry (LDV), are used.
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