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To decrease the emission of particles from a domestic wood-log boiler, particle traps based on inertial separation could be used. These could be designed and optimized with simulation tools, i.e. computational fluid dynamics (CFD) modeling. To find out whether the particle-tracking option in a commercial CFD code is reliable, a low-pressure impactor has been studied and each stage of the impactor simulated. By comparing experiments, it has been possible to determine the accuracy of the particle-tracking option for the CFD code. It has been shown that the particle-tracking procedure in the CFD software Fluent V6.0 offers good accuracy at velocities below 12 m/s with Reynolds numbers between 790 and 2150. Acceptable accuracy was shown for velocities of 20–170 m/s at Reynolds numbers between 960 and 2980. Considering actual flow velocities in a wood-log boiler and many other similar applications, the particle-tracking procedure should be accurate enough, at least for flows with a Reynolds number lower than 3000. Thus, it is recommended to use the software Fluent for simulations to find ways to reduce the particle emissions by use of mechanical traps. Three-dimensional simulations with either the Reynolds Stress Model (RSM) turbulence model, for accuracy, or the Renormalization Group (RNG) k–e model, to save calculation time, should be used together with the stochastic particle tracking. |
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