Sharif Digital Repository

One of the processes for energy carriers creating from biomass is Gasification process. The main products of this process are hydrogen and carbon monoxide. Output of this process has an average calorific value and sensible heat. Using sensible heat for preheating inlet air is one the ways for enhancement gasification processes. In this study gasification process is modeled as zone modeling. The humidity, pressure and air preheating effects on output gas composition and system’s layout were investigated. In the first and second scenario comparing the shifting of gas blower from downstream to upstream of gasification reactor is studied. It is showed the average temperature and number of... 

MILD combustion under high preheating and high dilution condition illustrates some interesting characteristics. Very low oxygen concentration in the reaction zone and reduced chemical reaction rates compared to conventional combustion are some of these features which make MILD combustion to be an unique type of combustion. In this work numerical investigation of a gas turbine model combustor (GTMC) was aimed to done using model of the EDC as turbulence-chemistry interaction combustion model. Modeling was performed by solving RANS equations and RSM equations for a 2D axisymmetric computational domain. The combustion chamber was investigated for both reacting and non-reacting conditions. A... 

The purpose of the present study is to develope an optimal model for analysis the impact of implementing a heat recovery system in a cement production line. For this goal, the energy reference system of a cement plant has been prepared, mass and energy balance sheets of the cement factory with dry production method, the characteristics of two high-energy streams have been identified in order to estimate the potential of heat recovery. Regarding the temperature range of the main hot streams, an appropriate cycle for generating electrical power from the lost heat, the Rankine cycle with organic fluid (ORC) has been formulated. The main question in the present project was how to relate the... 

Flameless combustion is among the newest combustion technologies that is used for reducing the pollutants in recent couple of decades. Within this combustion regime, diminution of super hot points throughout the combustion chamber along with decline in production of pollutant gases occur simultaneously. This kind of combustion often is created by applying two processes; first by preheating the fuel and/or oxydizer flows at the inlet to tempratures over the self-ignition level; and second with diluting the whole amount of fuel and oxidizer in the chamber. These two happen by using hot exhaust gas of the same chamber (via feedback) or of the previous section (in multi-section chambers).... 

High swirl combustors with circulative structures in the flow field, have a highly flame stability with a wide range of operating conditions. In this study, Sharif Gas Turbine Model Combustor (SGTMC) which is a double high swirl burner, was investigated experimentally and numerically. In experimental studies, SGTMC with different settings of swirlers is investigated in terms of flame lean blow-out(LBO), wall temperature, the exhaust gas composition and pollutant and also flame geometry parameters. Setting of burner are changed by variations in air fraction between inner and outer air inlets or swirlers’ vanes degrees and flow rotation directions. The results indicate that the concentrations... 

In this thesis numerical investigation on the effect of injecting plasma into the MILD combustion regime which is based on the low oxygen dilution and high preheated temperature, were carried out. The burner which was utilized in this study is a co-flow burner, consists of three coaxial channels. From the center to the outside, there is a fuel jet at the center part, a co-flowing dielectric barrier discharge (DBD), and a preheated air section that is vitiated. The DBD that was used in this study is generated between two coaxial electrodes of which the outer one (conical copper electrode) is covered with a dielectric material made of quartz. The burner is modeled in a 2D-axisymmetric... 

In this thesis, combustion of liquid fuel spray under the condition of hot and diluted oxidizer, has been investigated. To this end, a novel type laboratory-scale test rig was designed to study the physics governing the MILD-Spray combustion conditions with an applied approach. The underlined test rig eliminates the operational problems of its predecessor test stands and is used for a heavier fuel with much more complex chemical composition (kerosene). The test section is axially symmetrical, in which the fuel is injected by a pressure-swirl atomizer in the direction of hot and diluted co-flowing air. With the use of the aforesaid test rig, the effect of variables such as oxygen... 

In this study, the effects of using the co-flow air rotation on Kerosene combustion under air preheating and diluting conditions have been investigated. During this research, we have tried to achieve combustion under the MILD regime by simultaneous diluting, preheating, and swirling the co-flow air, which has also been achieved. To investigate the factors affecting the flame structure such as preheating temperature, dilution, swirl number, airflow rate, and also the type of fuel nozzle, the Sharif University MILD combustion test rig (SMCTR) has been upgraded in this research.The SMCTR has a symmetrically axial structure and provides a co-flow air with the desired temperature, swirl number,... 

In this study, the experimental study of kerosene mild spray combustion with the presence of the chamber has been investigated. The test rig that has been studied and improved is Sharif University of Technology's MILD Combustion Test Rig on a laboratory scale, which provides the possibility of studying spray combustion with preheating and high dilution. This test rig, while solving the problems of similar test stands, has the possibility of operating with liquid kerosene fuel, which is widely used in various industries. This test rig is axially symmetrical and provides the possibility of providing co-flow air with the desired temperature, swirl number and dilution rate for a liquid fuel...