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TheRglr Aert in CD Dispersed Phase Model(DPM): Overview Use to model particles, droplets, or bubbles dispersed(at low volume fraction) in a continuous fluid phase Compute trajectories of particle(or droplet or bubble) streams in continuous phase Compute heat, mass, and momentum transfer between dispersed and continuous phases Assume that dispersed phase occupies low volume fraction Less than 10%, but a high mass loading is acceptable Assume that particles enter and leave computational domain It should not be used for continuous suspension or settling DPM/Spray Applications- Categorized by physics Particulate flows Cyclones ers Pneumatic conveyors Coal-fired furnaces Droplet flows Sprays In-cylinder flows Combustors benchers Bubbly flows Aerators: bubble columns at low volume fractions nc DPMVsplay ApplicatioNs Categorized by Application Areas Production or processing Spray drying Spray cooling Spray reaction(absorption, roasting, etc. Atomized suspension(effluents, waste liquors, etc.) Powdered metals Treatments Evaporation and aeration Cooling(spray ponds, towers, reactors, etc.) Humidification and misting Air and gas washing and scrubbing Industrial washing and cleaning TheRglr Aert in CD DPM/Spray Applications (cont d Coating Surface treatment Spray painting Flame spraying Insulation. fibers and undercoating materials Particle coating and encapsulation Power generation/combustion) Oil burner, gas turbines, diesel and rocket fuel injection Miscellaneous edical sprays Dispersion of chemical agents Agriculture spraying Foam and fog suppression Printing and acid etching TheRglr Aert in CD DPM Equations Particle exchanges mass, momentum, and energy with continuum phase Particle trajectory calculation D x p+Fx 卡p mess-exchangG Heat transfer. heat-ex change m om entum-exchange 2=MA(T-)+h2+S d t P/dt Mass transfer ty pical continuous pha se control volume evaporation, boiling, reaction Coupling between phases: one way vs two-way coupling TheRglr Aert in CD Effects in Dispersed Systems hydrodynamics change in shape diameter particle-particle collision: coalescence or breakup particle-wall collision turbulence Physics heat transfer mass transfer change in composition TheRglr Aert in CD Particle Types Each injection needs one of the following particle types ype Physical effects Presumptions Inert Tracking, None heating cooling Dropl let Vaporization, Er nergy equation, boiling at least 2 species CombustionDevolatization Energy equation, heterogeneous at least 3 species reactions, heating Turbulent Dispersion Models When particles enter a turbulent eddy, they try to follow it for the time they are crossing the eddy This effect leads to lateral dispersion which has to be considered i modeling Two approaches are available Discrete random walk model Particle cloud model


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