Sharif Digital Repository

In this thesis, the rear part of a turbo-jet engine consisting of a one stage axial turbine and its exhaust nozzle are optimized numerically and experimentally. The decrease of total pressure loss of the flow in the stator and rotor blade cascades is investigated by change of two-dimensional profiles. The three-dimensional blade shape optimization is employed to study the effects of the axial turbine stator and rotor lean and sweep angles as well as radial distributions of stagger angle on the turbine performance. In adition, the effect of the turbo-jet engine exhaust nozzle on its performance is explored. Geometry candidates for the three-dimensional optimization algorithm of the axial... 

Prediction of axial flow turbine’s performance with different operating conditions due to the high costs and lack of reliable empirical data is always under developing. In this type of turbine, fluid flow is three-dimensional, viscous and highly turbulent. Nowadays, although a relatively detailed picture of the flow field can be obtained by the computational and numerical tools, but using of appropriate loss models in one-dimensional modeling for the performance prediction as well as optimization of the turbine in initial design phases, is a common trend.
In the current study, aerodynamic losses in the axial flow turbine are investigated. Several loss models for the axial flow turbines... 

In this research, it is aimed to convert a turbojet engine to a turboshaft by replacing the exhaust nozzle with a new designed power turbine stage. The design procedure is backed up with parametric studies to increase efficiency. At first a program is written for one dimensional modelling of the stage of axial turbine. By the way, the three dimensional modelling of the stage of axial turbine with Ansys-cfx business software is done. These methods are validated by modelling the gas generator turbine and comparison of their results with experimental results. Then the power turbine including the blades and the geometry of flow walls on shaft and casing are designed. The performance of power... 

Prediction techniques of axial flow turbine performance for different operating conditions are always developing due to high costs and lack of reliable empirical data. In axial gas turbines, fluid flow is three-dimensional, viscous, and highly turbulent. Nowadays, although flow field specifications are predicted accurately well using computational and numerical tools, the appropriate loss models are required for one-dimensional modeling and optimization in early design phases. In this research, an accurate and a complete investigation of aerodynamic losses in axial flow turbines will be discussed. Some suggested models for calculating losses in axial gas turbines, are considered and... 

In order to observe natural gas turbine phenomena and predicting engine behavior, we need to have a comprehensive simulator in every engine phase of design and analysis. Because of the high cost of manufacturing and prototype experimental tests, it's beneficial to access a gas turbine engine simulator. As well it's hard to make change in a manufactured engine, while we can change a simulator easily.Gas turbine is simulating in zero, one, two and three dimensions. In this project, we have studied previous researches and according to problem, among all simulations, we have studied the ATEC simulation and its assumptions in this thesis. Of these, zero and one dimensional simulations are simpler... 

Recent studies show a great number of micro hydro power potentials all over Iran. They have the capability to generate electricity for shops, residential areas, agricultural communities, and recreational tourism centers. In order to cover the micro hydro power potentials of the country, Sharif University of Technology and Iran Water and Power Resources Development Corporation decided to conduct a project to design and fabricate three types of micro hydropower for the first time in Iran. The potentials with low head and high discharge are located beside rivers and are appropriate places to install axial micro hydro turbine. In this project we tried to prototype an axial micro hydro turbine...