Sharif Digital Repository

Using Aspen Hysys to simulate burners and furnaces has been the focus of several studies in recent years. According to the studies and investigations carried out in the field of optimal design of the furnace, heating the air is one of the possible tasks to improve the performance and increase the efficiency. According to the obtained results, by adding air preheat, the efficiency increases from 92% to 96%. Also, to validate the simulation, two furnaces from Sepahan Oil Refinery furnaces were simulated in the field of oil production, which were simulated with an error of less than 1% in duty calculation, and according to the general results obtained, adding air preheat can increase the... 

Most motorcycles in developing countries use carburetor systems as the fuel delivery method especially for models with the cubic capacity of less than 150 cc. However, a small gasoline fuelled engines operating using carburetor system suffer from low operating efficiency, waste of fuel and produce a higher level of hazardous emissions to the environment. A retrofit fuel injection system (FIS) is a system that is developed to entirely replace the conventional carburetor system to improve its fuel economy and exhaust emissions providing a low-cost alternative in an effort to reduce fuel costs and air pollution. In this study, an electronic control unit (ECU) is designed for a fuel injection... 

The microfluidic fuel cell or laminar flow-based fuel cell is a membrane-less fuel cell which typically consists of two electrodes mounted within a T- or Y-shaped microchannel. Aqueous fuel and oxidant are introduced from the two inlets of the channel and flow together side-by-side toward the end of the channel. The Reynolds number in the microchannel is low, and hence viscous forces are dominant over the inertial forces. This causes the anolyte and catholyte form a co-laminar flow inside the microchannel which is required to maintain the separation of the fuel and oxidant and limit the reactions to the appropriate electrodes. In this work, a comprehensive numerical model of the microfluidic... 

The Fuel cell is an energy converter which converts the chemical energy of a chemical reaction to electricity and heat directly and without any pollution. One of the most important types of fuel cells is the proton exchange membrane (PEM) fuel cell. The importance of PEM fuel cells is a result of their high energy density, quick start up ability, lower operating temperature, high efficiency and low or zero emissions. Catalysts play an important role in both costs and durability of PEM fuel cells. Alloying the Pt with other metals can increase the activity of the catalysts of the fuel cells and also reduces the amount of costly Pt. In this study, the nanoparticles of Ni were added to the... 

Gas turbine engine control is a demanding task that requires the regulation of the thrust as well as the satisfaction of the limitations such as engine aerodynamic instability, over temperature and over speed. Fuzzy logic is an attractive technique for the control of poor understood unmodeled, or complex systems especially where the experience of human operators is available to provide qualitative rules. In such cases, it has been found that control decisions can be made on the basis of linguistic measures or fuzzy algorithms. The controller that is designed on the basis of this theory is called fuzzy logic controller. The main objective of this thesis is hardware implementation of fuzzy... 

Concerns like fuel cost, pollution and global warming has made it necessary to look for new energy solutions. Renewable and alternative energies have proven themselves to be helpful in this matter. Renewable energy(RE) is the energy that comes from natural resources such as sunlight, wind, rain, tides, waves and geothermal heat, which are naturally replenished at a constant rate. Renewable energies are environmentally friendly, not cheap at the beginning but naturally available in a constant rate and wide spread, unlike fossil fuels that are localized in the limited places. In this thesis in order to generate environmental friendly power we consider two renewable energy resources: wind and... 

This thesis contributes to development of a microscopic simulation of arterial traffic flow to estimate the impact of behaviour and culture of Iranian drivers on fuel consumption. To accomplish this task it is necessary to use a simulation software. But as existing simulation softwares include assumptions which are not applicable to traffic culture and architecture in Iran, a new software was developed. This software is based on non-lane disciplined driving parameters. The output is an estimation of average consumed fuel by a vehicle in general or a specified service condition. This estimation is an important parameter in decision making and planning for the future traffic and environmental... 

Air pollution is a prevalent and pressing issue in Tehran, with significant impacts on both the environment and human health. this study uses statistical techniques, such as Pearson correlation, to determine the direction of influence of meteorological parameters on air pollutant concentrations, and Convergent Cross Mapping to quantify the causal relationship between meteorological parameters and ambient air pollutant concentrations, as well as feedback effects. Additionally, the research delves into the correlation between consumption of fossil fuels and air pollutants, as well as the relationship between lung cancer incidence and mortality by histological subtype and long-term exposure to... 

We present here an analysis of controlling the Polymer Electrolyte Membrane Fuel Cells (PEMFCs) using the Q-learning algorithm, the most widely-known among reinforcement learning (RL) techniques. The method is to train the controller to guide and sustain the fuel cell power output in the 2.5 kW mark by way of manipulating elements of the reaction subsystem including the fuel cell current, the relative humidity, and the anode/cathode pressures. As the Q-learning algorithm need be implemented within a fuel cell simulation environment, the mathematical model known as Amphlett steady-state model of the PEM fuel cell was employed. The semi-empirical nature of this model necessitates the... 

Storage of the spent nuclear fuels is one of the topics of interest in recent years and many researches have been conducted in this field in order to design storage casks for spent nuclear fuels. In this study, thermal-hydraulic analysis of a dry storage cask for Bushehr Nuclear Power Plant spent nuclear fuels is carried out. Geometry of the analyzed cask is taken from a Russian transportation cask TK-13. Drawing of the geometry is achieved with SolidWorks and it’s meshing is completed in Gambit. 3 different cases were considered for cask’s geometry and design: cask without spacers inside, cask with spacers inside, and cask with spacers inside and fins on the outside surface of the cask.... 

Improper management and inefficient methods such as direct disposal to the environment to stabilize municipal solid waste and sewage sludge in addition to creating environmental problems due to the existence of food cycles, will also cause problems on human health. In this study, a hybrid system is modeled to produce value added in the form of energy and nutrients from a combination of food waste and secondary sewage sludge. This system has 3 subsystems, two-stage anaerobic digestion process that will be accompanied by the production of your bios (hydrogen + methane), the process of recovery of phosphorus from the sludge out of the digestion process and the system of simultaneous production... 

Fossil fuels provide the most needs of the world's energy, however, continues to lead to two key problems. The first problem is their limitation, and the second problem is the creation of serious environmental issues. Therefore, the need for renewable energy sources is felt more than ever.As an energy source, hydrogen is the lightest, most efficient and cleanest fuel. One of its unique properties is efficiency, the production of electricity by fuel cells through the electrochemical process, has far greater efficiency than of mechanical energy production from fossil fuels in internal combustion engines or energy production in thermal power plants. A fuel cell is a device that converts... 

The issue under discussion in this paper is to optimize the fuel consumption of the Toyota Prius hybrid car. In order to solve this problem, the ADVISOR design model used by NREL in the Matlab / Simulink environment has been used. Various parts of this model are described. The optimization performed on this issue is based on the emotional controller. This controller works by simulating learning in animals based on encouraging and punishing them. With the introduction of the controller, the model and its inclusion in the fuel consumption control and its implementation have achieved good results. In the initial state and the controller in the model, the fuel consumption was 4.9 liters per 100... 

The Fukushima accident is one of the reasons why the spent fuel pool (SFP) is an important safety element. The large amount of spent fuel inside the spent fuel pool has made it a source of hydrogen and radioactive material in the accident of any disturbance to pool cooling. Although the loss of spent fuel pool cooling system accident has a slow transient, it can lead to disasters if you ignore it. In this project, spent fuel pool of Bushehr Power Plant unit ‘I’ was simulated by Ansys Fluent and the natural circulation of fluids in the absence of cooling system was investigated. The distribution of water temperature in the pool was investigated for the worst possible spent fuel pool loading... 

Fuel cell is a very attractive technology for clean electricity production and has a wide range of applications from industry to transportation and power generation. There are several issues that prevent the development of this technology widely. Rapid degradation of fuel cells during operation is one of them. Online monitoring of operational parameters in order to control and optimize the effective variables of power generation and life of the fuel cell considered as an important way to mitigate fuel cell’s degradation. In this research, a set of models were developed to calculate the voltage, current, corrosion, as well as the fuel cell system state variables instantaneously. Two robust... 

One of the challenging issues in Iran's nuclear talks and Group 5+1 countries is the amount of Iran's enrichment capacity and the number of centrifuges needed to meet this demand. In this regard, Iran has recently announced that the basis for determining its enrichment capacity is the supply of fuel for the Bushehr power plant.Modeling and optimizing of gas centrifuge cascade is one of the most important problems in fuel cycle and isotope separation fields. To achieve this goal it is needed to comprehend of single centrifuge operation. Knowing the effectofsingle centrifuge parameters, it is easy to design a desired cascade. Minimizing the number of machines in the cascade is an anticipated... 

The transportation sector is the largest oil consumer sector in the world. Iran is no exception to this, and the transportation sector, especially road transport, has a large share of oil and energy consumption in Iran. Diesel supply security in The road transport system has been implemented but it has not been properly managed for gasoline, as the country has been an importer of gasoline for many years and large cities suffering the pollution caused by light duty vehicles. Analyze the transportion of light duty vehicle by the game theory method can detect the barriers to reducing fuel consumption. For this purpose, the main Actors affecting the transport of light duty vehicles - people,... 

In this thesis a computational method for the design of optimum nozzle contour with consideration for chemical reactions has been presented. This method combines the method of characteristics, CFD and an optimization algorithm to develop a nozzle suitable for a specific operational condition. First using the method of characteristics an isentropic nozzle contour is achieved. then using the FLUENT solver, this initial contour is solved for flow containing finite-rate reactions and boundary layer effects and by iterating this process combined with an optimization algorithm, an optimum nozzle is found. Properties took into consideration in this method, in addition to chemical reaction between... 

The present M.Sc. thesis consists of two sections including the static calculation and neutron noise calculation in rectangular and hexagonal geometries. The multi-group, two dimensional neutron diffusion equations and corresponding adjoint equations are solved in the static calculation. The spatial discretization of equations is based on Average Current Nodal Expansion Method (ACNEM). Size of nodes is the same size of the fuel assemblies in modeling both of rectangular and hexagonal geometries. The results are benchmarked against the valid results for BIBLIS-2D and IAEA-2D benchmark problems. In the second section, neutron noise calculations are performed for two types of noise sources,... 

The energy systems efficiency is a great issue confront power plants professionals. Besides using high-tech components in power plants, plant operation optimization can significantly improve energy efficiency and economic performance, as efficiency of plant components generally depends on operating conditions. In addition, system preventive maintenance can reduce plant operation and failure costs, however it is also costly when done frequently. Therefore, optimizing operating conditions and preventive maintenance intervals can minimize the expected total cost of plant due to operation, failures and preventive maintenances. In recent years, the use of optimization models to determine plant...