الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 101 |  |  |
| | | from | 101 | | |
Abstract
One of the most difficult issues in reducing fuel consumption and emissions is to improve the efficiency of combustion systems. Therefore, numerous studies have been conducted, with the assistance of modern technology, to build combustion systems that produce the best results in operations, save energy, and protect the environment from the risk of harmful emissions produced and minimize them, particularly NO and CO.
The main objectives of the present study may be described in three parts: The first part is studying the blow-off limits of Liquified Petroleum Gas (LPG)/ air mixture for different swirl numbers (0.5, 0.75, 1.0 and 1.5) and number of fuel nozzle used (4, 9, and 16). In the second part, the effect of swirl number on inverse and normal diffusion flames characteristics (flame shape, flame length, temperatures distributions and species concentrations) were studied at constant inlet equivalence ratio (Φ) of 1.0 for all swirl numbers. In the third part, the effect of inlet equivalence ratio (Φ) of 0.75, 1.0, 1.5 and 2.0 for all swirl numbers on inverse and normal diffusion flame characteristics were experimentally investigated.
To study the previous parameters, a test rig was designed and construted which includes an air line, LPG fuel line, traverse mechanism and burner head. The effect of swirl number and equivalence ratio on the temperatures pattern, visible flame length and the combustion species concentrations were studied.
The results showed that, the Inverse Diffusion Flame (IDF) has high stability for low swirl number and by increasing the number of fuel nozzles the stable region size increased. The visible flame length for the IDF and the Normal Diffusion Flame (NDF) were decreased by increasing the swirl number. Since the length of the IDF less than the NDF, so the IDF is suitable for limited or small size of combustion chamber. Additionally, by increasing inlet equivalence ratio from 0.75 to 2.0, the visible flame length was increased by about 39%, 91%, 108%, and 620% for IDF, and by about 13%, 15%, 19%, and 18.6% for NDF for air swirl numbers of 0.5, 0.75, 1.0, and 1.5, respectively. from the extensive experimental results an empirical formula was obtained for getting the flame length for the NDF and the IDF at function of inlet equivalence ratio from 0.75 to 2.0 and swirl number from 0.5 to 1.5. Also the results showed that at chemical reaction region the NDF has higher values of NO, CO and CO2 concentrations compared with the IDF, so that IDF is more suitable for protecting the environment instead of the NDF.