Comparison of Atmospheric Dispersion in a Large Terrain of Kaiga Atomic Power Plant with Simple Terrain Assumption against actual Complex Terrain Modelling
Author(s)- Pavan K. Sharma, Gera B, Ghosh A. K
Pollutant dispersion in the atmosphere is an important area wherein different approaches are followed in development of good analytical model. The analysis based on Computational Fluid Dynamics (CFD) codes offer an opportunity of model development based on first principles of physics and hence such models have an edge over the existing models. The present paper is aimed at bringing out some of the distinct merits and demerits of the CFD based models. A brief account of the applications of such CFD codes reported in literature is also presented in the paper. The choice of codes and the features to be employed from within the code for a specific problem needs expertise in thermal-hydraulics and numerical techniques. Brief guidelines towards this objective are also covered in the paper. An illustration of use of CFD code for pollutant dispersion studies is also included in the paper which clearly brings out the success and advantage of CFD based approach for modelling complex terrain.
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CFD Modeling and Experimental Validation of Combustion in Direct Ignition Engine Fueled with Diesel
Author(s)-Umakant V. Kongre, Vivek K. Sunnapwar
This paper describes the development and use of sub models for combustion analysis in direct injection (DI) diesel engine. In the present study the Computational Fluid dynamics (CFD) code FLUENT is used to model complex combustion phenomenon in compression ignition (CI) engine. The experiments were accomplished on single cylinder and DI engine, with full load condition at constant speed of 1500 rpm. Combustion parameters such as cylinder pressure, rate of pressure rise and heat release rate were obtained from experiment. The numerical modeling is solved by unsteady first order implicit, taking into account the effect of turbulence. For modeling turbulence Renormalization Group Theory (RNG) k- ε model is used. The sub-models such as droplet collision model and Taylor Analogy Breakup (TAB) model are used for spray modeling. The wall-film model is used to assess spray-wall interaction. Modeling in-cylinder combustion, species transport and finite-rate chemistry model is used with simplified chemistry reactions. The results obtained from modeling were compared with experimental investigation. Consequences in terms of pressure, rate of pressure rise and rate of heat release are presented. The rate of pressure rise and heat release rate were calculated from pressure based statistics. The modeling outcome is discussed in detail with combustion parameters. The results presented in this paper demonstrate that, the CFD modeling can be the reliable tool for modeling combustion of internal combustion engine.
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