Sharif Digital Repository

In this work, a double-high swirl gas turbine model combustor (GTMC) has been experimentally investigated to identify the effects of air partitioning and swirlers geometry on combustion characteristics in terms of flame stability, exhaust gas temperature, NOx generation, and combustion efficiency. This high swirl model combustor is originally developed in the German Aerospace Center (DLR) and known as GTMC and recently reconstructed at Sharif University's Combustion Laboratory (named as SGTMC). Here, SGTMC run for liquefied petroleum gas (LPG) fuel and air oxidizer at room temperature and atmospheric pressure. Eleven different burner geometries, M1-M11, are considered for the aims of this... 

A gas turbine shaft is generally exposed to high-temperature gases and may seriously be affected and overheated duetotemperature fluctuationsinthe combustion chamber. Vortex flow inthe combustion chamber may increase the heat release rate and combustion efficiency, as well as control the location of energy release. However, this may result in excessive temperature on the combustor equipment and gas turbine shaft. In this study, a new gas turbine combustion chamber implementing a liner around the shaft and the liquid-fuel feeding system is designed and fabricated. The influences of parameters such as the Reynolds number and the equivalence ratio are studied. Experimental results are compared... 

Gas turbine shaft is generally exposed to high temperature gases and may seriously be affected and overheated due to temperature fluctuations in the combustion chamber. Considering vortex flow in the combustion chamber, it may increase the heat release rate and combustion efficiency and also control location of energy release. However, this may result in excess temperature on the combustor equipments and gas turbine shaft. Vortex flow in the vortex engine which is created by the geometry of combustion chamber and conditions of flow field is a bidirectional swirl flow that maintains the chamber wall cool. In this study a new gas turbine combustion chamber implementing a liner around the shaft... 

In this paper, the effects of a baffle plate on flame deflection and its throttling are investigated numerically in a combustor consuming jet propellant JP. We study the plate effects on the resulting soot volume fraction, soot particles diameter, mass fractions of carbon monoxide (CO), carbon dioxide (CO2), and benzene (C6H6). We use a two-equation turbulence model, a PAH-inception two-equation soot model imposing oxidation due to OH agents, a detailed chemical kinetic consisting of 121 species and 2613 elementary reactions, and the flamelet combustion model to perform the current study. We also take into account the turbulence-chemistry interaction using the presumed-shape probability... 

A new experimental facility was designed, fabricated and tested to model and study the possibility of applying the bidirectional swirl flow on the combustion chamber of airbreathing subsonic ramjet engine. Appropriate intake was designed to convert axial external air to tangential swirl flow inside the combustion chamber. Inlets with appropriate angles conduct the swirl flow into the chamber and create bidirectional swirl flow field in the combustion chamber. This flow field has been modeled theoretically to determine the velocity field characteristics by previous researchers. Bidirectional swirl flow in liquid fuel ramjet engines has the proven advantage of keeping the combustion chamber... 

A numerical framework was carefully developed to simulate the combustion of heavy-fuel-oil (HFO) in a large-scale boiler. The present numerical solutions were compared with the measured data of a laboratory benchmark test and on-site operational data of the chosen HFO-fired boiler. Next, the developed framework was used to perform sensitivity analyses aiming to reduce the NO emission from the HFO-fired boiler without any adverse effect on its combustion performance. Practically, this study focused on re-adjustments of 24 working burners, which could control combustion in the HFO-fired boiler. The early outcome showed that the boiler NO emission and its combustion performance could be... 

Low temperature combustion potentially can improve engine efficiency coupled with the benefits of low nitrogen oxides, and particulate matter emissions, and vice versa high unburned hydrocarbon and carbon oxide emissions through in-cylinder fuel reactions. In this survey, the experiments were carried out using a modified one-cylinder reactivity controlled compression ignition engine, dual-fueled diesel/compressed natural gas and biodiesel/CNG, to investigate the effects of direct injection strategies on the engine combustion efficiency and emission characteristics. Different ratios of biodiesel blends at different premixed ratios were applied to the dual-fuel engine. The results showed that... 

Aiming at improving efficiency in combustion systems, the study on droplet behavior and its trajectory is of crucial importance. Vortex engine is a kind of internal combustion engine which uses swirl flow to achieve higher combustion efficiency. One of the important advantages of designing vortex engine is to reduce the temperature of walls by confining the combustion products in the inner vortex. The scopes of this investigation are to study vortex engine flow field as well as effective parameters on fuel droplet behavior such as droplet diameter, droplet initial velocity and inlet velocity of the flow field. The flow field is simulated using Reynolds Stress Transport Model (RSM). The...