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    Item type:Publication,
    CFD Simulations of High Efficiency Gas Cyclones: An Influence of Dustbin Geometry
    (2021-01-01)
    Pechmanee, Pitiwat
    ;
    Namkanisorn, Apinan
    ;
    Wattananusorn, Santi
    ;
    Bumrungthaichaichan, Eakarach
    The unsteady state simulation of gas-solid cyclone separator was carried out to investigate the performances of 0.29 m diameter (D<inf>B</inf>) cyclones with five different dustbin geometries, including dustbin without dipleg (cylindrical bin) and dustbins with 0.5D<inf>B</inf>, 1.0D<inf>B</inf>, 1.5D<inf>B</inf>, and 2.0D<inf>B</inf> (divergent conical bin) height divergent conical diplegs. The diameter and total height of five dustbins were 1D<inf>B</inf> and 2D<inf>B</inf>, respectively. The gas flow and turbulence fields inside the cyclones with the Reynolds number of 280,000 were simulated by Reynolds averaged Navier-Stokes equations (RANS) with Reynolds stress model (RSM). The collection efficiencies were investigated by using discrete phase model (DPM). For model validation, the simulated velocity profiles of the cyclone with cylindrical dustbin have been compared to the previous experimental data available in literature and were in good agreement with the previous results. Further, the simulated results revealed that the Stairmand cyclone with divergent conical and simple cylindrical dustbins respectively represented the highest and lowest collection efficiencies indicated by 50% cut-off diameter, which corresponded to the diameters of 1.692 and 1.744 microns, respectively.
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    Item type:Publication,
    CFD modelling of pump-around jet mixing tanks: a discrepancy in concentration profiles
    (2018-10-03)
    Bumrungthaichaichan, Eakarach
    ;
    Namkanisorn, Apinan
    ;
    Wattananusorn, Santi
    Jet mixing tanks are important in chemical processes. Over the past two decades or so, computational fluid dynamics (CFD) has been employed to study jet mixers. The shortfalls of the previous CFD models were the discrepancy in concentration profiles between simulation and experiment and the absence of exact inlet turbulence conditions. So, in our present work, the CFD model was developed to investigate the proper conditions for jet mixing tank simulation and improve the accuracy of concentration profile prediction by using an appropriate grid arrangement, a realizable k-epsilon model, and a second-order upwind discretization scheme. The results revealed that the CFD model with proper inlet conditions predicted the overall mixing time well and somewhat improved the predicted concentration profiles. Further, the reasons for discrepancies in concentration profiles were inappropriate inlet turbulence conditions and overprediction in total momentum available for mixing due to the flat top liquid surface assumption. In addition, this discrepancy may be caused by the dynamic response of concentration measuring device.