Numerical Analysis of Coal Combustion in Circulating Fluidized Bed
combustion of coal is used in circulating fluidized bed combustion system. This work is concerned about gas–solid two-phase mixtures flowing upwards through the fast beds. The type of information resulting from various ways of analyzing the pressure variations and the effect of superficial velocity on pressure in fluidized beds are discussed. This paper presents the standard k–є and two-phase turbulence model used to describe the gas–solids flow in a CFB.The analysis of temperature and density in coal combustion is done by discrete phase model (DPM) and non pre mixed combustion in species model through the PDF file creation in DPM model. The flow temperature and density in the system were modeled by solving the continuity and momentum equations of the gas flow by using the CFD analysis. The fluidizing velocity has been taken as 4 m/s and the effects of operating parameters on mole fraction, mean density and mean temperature are discussed in this paper. It is observed that the mean density of minimum and maximum mean mixture fraction along the scaled variance is significant.
Study, Evolution, Design and Analysis of CFBC Boiler for usage of Biomass as a Fuel
In the work some parts of a laboratory scale CFBC are designed and developed with in department. Biomass rice husk were additionally ready and tested with in the circulating fluidized bed combustor system. A mathematical model was additionally developed to study the physico-chemical parameters of a 30 MW circulating FBC system at Bharathi cpp. Effect of the different parameters like particle size, bed temperature , ash content and moisture in fuel on the bubble diameter, minimum fluidization velocity and superficial velocity have been studied. Index Terms CFBC boiler ,Design , Analysis , CPP . ________________________________________________________________________________________________________
Supersonic Combustion of Kerosene/H2-Mixtures in a Model Scramjet Combustor
Liquid hydrocarbon supersonic combustion has been experimentally investigated. Kerosene was burnt in a steady. vitiated Mach 2.15 - air flow of a model scramjet combustor. The fuel is injected into the supersonic air stream by means of pylons. The effervescent atomisation method has been employed such that the liquid fuel is injected as a spray. By means of the Mie scattering technique the fuel jet structure was visualised and the evaporation rate estimated. The mechanisms of ignition and combustion of the kerosene/H2-mixture were studied and compared with the case of hydrogen combustion. Combustor ignition limits have been determined. Fuel-specific combustion phenomena are discussed. It was found that for the kerosene combustion a gas dynamic feedback mechanism strongly affects the supersonic combustion process.