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Major advances have been made in the development of bagasse combustion technologies and understanding the many processes involved in bagasse combustion and steam generation. CFD modeling has come to form an integral and critical part of this progression. The experience with CFD in the sugar industry through Sugar Research Institute has encompassed the full range of applications from fundamental code...
The tests and simulations in this study characterize the chemical structure of pressurized pulverized coal flames, particularly (1) how the O 2 in simulated near-burner flame zones is apportioned among the various fuel components; and (2) the burner operating conditions and mechanisms that most strongly affect flame structure. CFD simulations resolved the structures of flames of a subbituminous...
The combustion process and fluid flow in a compression ignition natural gas engine with separated chamber are studied by coupling Multi-dimensional Computational Fluid Dynamic (CFD) code FIRE with detailed chemical kinetic mechanism. The calculated data are first validated by experimental data. Subsequently, Multidimensional simulations at a baseline condition are carried out to investigate combustion...
Advanced combustion kinetics models are of widespread use to predict carbon losses from coal combustion. However, those models cannot completely capture the complexity of the real phenomena affecting the fluid flow in a full-scale utility boiler, such as burner-to-burner interactions and bottom hopper vortexes or reversed-flows, and usually underpredict carbon in ash values. The use of CFD codes offers...
Computational fluid dynamics is a widely used tool in optimizing natural gas burners, for instance, for emission issues. Especially, a further reduction of NO x emissions is of interest. However, due to computational efforts calculating three-dimensional turbulent flames, there is the necessity for simplified models in order to simulate the combustion reactions and the NO x formation,...
This paper discusses the application of FLUENT™ in the analysis of grate-fired biomass boilers. A short description of the concept used to model fuel conversion on the grate and the coupling to the CFD code is offered. The development and implementation of a CFD-based deposition model is presented in the reminder of the paper. The growth of deposits on furnace walls and super heater tubes is treated...
The detailed intake, spray, combustion and pollution formation processes of compression ignition engine with high-octane fuel are studied by coupling multi-dimensional computational fluid dynamic (CFD) code with detailed chemical kinetics. An extended hydrocarbon oxidation reaction mechanism used for high-octane fuel was constructed and a modeling strategy of 3D-CFD/chemistry coupling for engine simulation...
In this study, computational fluid dynamic (CFD) and kinetic models were used to investigate the relative performances of coal volatiles and natural gas reburning. This modeling approach considers fluid dynamic and non-isothermal effects, which were not considered in past laboratory flow reactor studies. The commercial CFD code FLUENT 6.1 was used to predict the residence times and temperatures for...
Pressurized high temperature black liquor gasification has the potential to significantly improve the efficiency of energy and chemical recovery in the pulping industry and to enable new processes, e.g. production of renewable automotive fuels from the formed synthesis gas. However, the current process is still considered as novel and the interest in validated computer models for scale-up and process...
This work arises from substantial problems found in the modelling of the gasification and combustion of solid fuel, both coal and biomass in the following different systems:•Coal fired non-slagging cyclone combustors.•Pre-calciners on cement plant.•Fuel rich inverted cyclone combustors used to simulate the time temperature history of large utility boilers.•Cyclonic gasifiers for sawdust and direct...
CFD codes and advanced kinetics combustion models are extensively used to predict coal burnout in large utility boilers. Modelling approaches based on CFD codes can accurately solve the fluid dynamics equations involved in the problem but this is usually achieved by including simple combustion models. On the other hand, advanced kinetics combustion models can give a detailed description of the coal...
A CFD investigation has been carried out about the performance of a 600MW e tangentially coal-fired boiler, focusing on the reduction of NO x attainable by using overfire air. To this purpose, a comprehensive combination of NO x chemistry models has been used, coupled with the numerical simulation of fluid and particle flow, solid fuel combustion and heat and mass transfer...
In CFD simulation of diesel combustion, the predictive capabilities of the spray model play the most important role. Consequently, under the strict guidelines of the V&V, a method to adjust parameters of diesel spray model WAVE to accompany with the in-cylinder physical progress has been investigated in this paper. Moreover, the simulation of the spray has been validated by high-speed photography...
Within the computational methods used for the prediction of unburned carbon, coal combustion kinetics models, generally developed from the study of the real combustion process in experimental facilities, has the advantage to simulate the coal combustion process in a very realistic way. However, these models need the fluid and thermal behaviour in the boiler, which is usually obtained from simplified...
This paper presents a computational fluid dynamics model of a methanol burner. Special emphasis was placed on the study of the liquid atomization and combustion process. Linearized Instability Sheet Atomization (LISA model) was employed to simulate the fuel atomization process. Predictions of droplet diameters, droplet trajectories, temperatures and gas concentrations are presented and compared with...
In the last decade 3D-CFD has been successfully established for the simulation of IC-engine fuel spray formation and propagation processes. The accuracy of the calculation results, however, strongly depends on the models adopted for simulation of the primary and secondary atomization processes. Hence, careful validations of the individual models serve as major prerequisites for the successful analysis...
This paper describes the development and validation of an advanced boiler simulation tool for Units 1 and 2 at the Youngheung Power Plant in South Korea. By combining 3-D computational fluid dynamics (CFD) analysis of the furnace with a 1-D steam-water side model it is possible, for example, to simulate the effects of burner and SOFA settings, firing patterns and coal blending on the boiler efficiency...
A CFD simulation of pulverized coal and straw combustion using a commercial multifuel burner have been undertaken to examine the difference in combustion characteristics. Focus has also been directed to development of the modeling technique to deal with larger non-spherical straw particles and to determine the relative importance of different modeling choices for straw combustion. Investigated modeling...
CFD-based engineering models can be cost-effective tools in determining technical feasibility of clean coal-fired power generation technologies like NO x mitigation strategies targeting the reduction of acid rain and smog. Their actual effectiveness depends on their capability to provide realistic engineering estimates without arbitrary adjustment of model parameters. This investigation focused...
In the current work the co-combustion of Solid Recovered Fuels’ (SRFs’) with brown coal in large scale pulverised coal boilers under different operational conditions is numerically investigated. In order to overcome the difficulty of the complex, inhomogeneous nature of waste recovered fuels, SRF is modelled as a mixture of two different fractions, the biogenic and the plastic one. For each fraction...
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