Comparison of Turbulence Sub-Grid Scale Model for Modeling of Large Scale Pool Fire Using LES

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Abstract

The Smagorinsky and One-Equation sub-grid scales (SGS) for modeling of large scale pool fire using Large Eddy Simulation (LES) has been used and compared. The fire heat release rate was 2.07 MWatt and the fuel was Methane. Based on the mixture fraction approach and infinity fast chemistry assumption, the mean velocity profile and turbulence kinetic energy are calculated and compared against experimental measurements. The predicted time-averaged velocity is in good agreement with the experimental data. The computed velocity time history is better predicted using One-Equation SGS model than Smagorinsky SGS model at about 5 percent. The computational time of One-Equation is about 16 percent higher than Smagorinsky for the test case. The difference between time-averaged vertical and horizontal velocity are about 4 and 5 percent. In the area where the pulsating behaviour of the fire is important, the One-Equation model is recommended. For the one which averaged values are dominated, Smagorinsky SGS recommend reasonable results.

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