Sharif Digital Repository

The produced crude oil from the petroleum reservoirs usually has a value of brine (water and salt) this matter can be caused the corrosion of refinery equipment. The large part of this brine creates a stable emulsion with oil, that it couldn't be separated easily. For separation and demulsification of this emulsion, some chemical, mechanical, thermal and electrical methods can be executed. In chemical method, demulsifier materials can be added to water-in-oil emulsion. Different parameters such as properties of oil, type and concentration of demulsifiers, volume factor of water and etc., can affect the efficiency of water-in-oil emulsion separation. In this study, emulsification mechanism,... 

An important step in the early stages of an oilfield development is the accurate identification of the location of production and injection wells which has a significant impact on productivity and profitability of the reservoir. Recently, operation companies in petroleum industry focus on production optimization, recovery enhancement and cost reduction; as a result, application of non-conventional wells (NCW) or non-vertical wells have dramatically increased. Well placement optimization is a complicated task as it is a function of several contributing factors including reservoir heterogeneities and economic constraints. The complexity of this task increases when it is considered as a... 

At the early stages of production, oil reservoirs may have enough energy to push the oil from the reservoir into the wellbore and subsequently from the wellbore to the surface. When the reservoir energy is too low for the well to flow, or the production rate desired is greater than the reservoir energy can deliver, using some kind of artificial lift method to provide the energy to bring the fluid to the surface, seems to be necessary. Continuous flow gas lift is one of the most common artificial lift methods widely used in the oil industry during which, at appropriate pressure, gas is injected in a suitable depth into the tubing to gasify the oil column, and thus assist the production. Each... 

One of the major problems in directional and extended reach wells is poor hole cleaning. Directional and horizontal drilling is more complex than vertical wells. Ineffective particles transport leads to several undesirable issues during drilling. This thesis analyzed all parameters which have directly affected directional hole cleaning. The thesis is based on an experimental set-up designed in Sharif University. In the experimental work, two types of drilling fluid, Newtonian and Non-Newtonian with numerous rheological parameters, three different flow rate, three various nozzle sizes and three individual RPMs in three distinct inclinations 30°, 60° and 90° were used to simulate. Also, to... 

After the rise of the automotive industry, aluminum wheels have superseded steel counterparts due to their numerous advantages. Foremost among these benefits is their reduced weight, leading to fuel savings and diminished environmental impact. Moreover, aluminum wheels offer enhanced aesthetics and greater strength in comparison to steel alternatives. This thesis focuses on the geometrical optimization of an aluminum wheel model conforming to the standards set by Iran's Department of Standards, aiming to achieve a higher strength-to-weight ratio. While prior research works have mainly focused on weight reduction while maintaining strength within approved standards, this thesis aims at the... 

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... 

Iran is one of the biggest suppliers of oil in the world. Iran's economy highly depends on its oil. Iran has valuable old reservoirs that need some techniques to optimize their production of it.Determining optimal well placement and control is essential to maximizing production from an oil field. The reservoir optimization problem is an extraordinary complex problem that depends on many factors such as flow pattern, well specification, reservoir properties, and environmental and economic criteria. Finding the locations of injection and production wells and other optimum operational parameters in the oil industry are very important and have a great influence on the operation of the... 

In this thesis, the process of laser assisted machining (LAM) of metal matrix composites (MMC) is experimentally studied. The effects of process parameters (cutting speed, feed rate and depth of cut), laser parameters (laser power, laser frequency and laser beam angle), and the percentage of reinforcing particles on the tool wear and the surface roughness are investigated. Furthermore, the effects of these parameters on the built-up edge (BUE), chip shape, and workpiece temperature are explored.The experiments were performed using uncoated tungsten carbide and PCD tools under dry conditions. In order to analyze the sensitivity of the process parameters, the Plackett-Burman method was used... 

Nowadays, gas turbines are from the most widely used devices in terms of power generation. According to their vital role in suppling electrical power required for daily life and their widespread application in power plants, tremendous efforts have been made to improve the efficiency of gas turbine working cycle. One of the most applicable methods to optimize a gas turbine is to cool the compressor inlet air. Applying an absorption chiller is a wisely technique especially when it comes to hot and humid weather condition. In this thesis, effects of applying an absorption chiller with specified technical facts on the performance of gas turbines, which are now functional in Kish Island power... 

Nowadays, the lattice Boltzmann method has been widely used by scientists and engineers as an alternative to conventional numerical solvers for the Naiver-Stokes equations. The drag force decrease on the surfaces in industrial applications special in transport industries has always been of special importance. In the current research, the effects of the drag decrease has been investigated by making some rectangular grooves on the millimeter and micrometer scale on a flat surface that has been under external laminar flow of a single-phase fluid with the uniform type. Making grooves on the surfaces usually lead to change the contact area from the solid-fluid to fluid-fluid in the grooves area.... 

The application of computational fluid dynamics (CFD) has been growing rapidly in biomedical engineering. The altered hemodynamics inside the blood vessels plays a key role in the development of the arterial disease called atherosclerosis, which is the major cause of human death worldwide. Atherosclerosis is often treated with the stenting procedure to restore the normal blood flow. A stent is a tubular, flexible structure, usually made of metals, which is driven and expanded in the blocked arteries. The presence of non-biological device in the artery causes inflammation or re-growth of atherosclerotic lesions in the treated vessels. Several factors including the design of stents and type of... 

In modern era, standpoints about atrium design have been revolutionized. In modern architecture, atrium not only designed for illuminating purposes but also designed by natural ventilation and passive cooling policies. Numerous parameters are making role in thermal efficiency of Atrium. A couple of these parameters are Atrium shape and openings area. In high rise atria the lower level rooms enjoy the advantage of buoyancy-driven ventilation while the upper level rooms suffer from its lack or weak presence. One strategy to solve this problem is designing building with various opening area in different heights but manipulating the opening size is restricted by some facts. Excessive Opening’s... 

This study is aimed at simulation of the flow of air and aerosol particles through a single square fibrous filter media made up of micro fiber as well as the importance and effect of different fiber’s cross-sectional shapes and arrangements on particle deposition and filtration efficiency. An understanding of the role of changing the laminar flow regime from laminar vortex shedding "(Re"=100" and Re"=200")" to subcritical flow "(Re"=1000")" developed for the first case. The study deals with parallel and staggered multi-fibrous filter media with circular, elliptical, and equilateral triangular micro fiber’s cross-sectional shape of the transient laminar vortex shedding flow "(Re"=200")" .... 

Ever-increasing energy consumption and consequent extensive greenhouse gas (GHG) emissions are two major urgent problems faced by all human beings in the 21st century. As a major contributor, the energy production section appears to be the most suitable field where further improvements could be explored to tackle these problems. Multi carrier energy system is a typical type of next generation energy production technology with higher energy efficiency and lower/zero GHG emissions. The conversion of energy between different carriers establishes a coupling of the corresponding power flows resulting in system interactions. The investigation of such phenomena requires the development of tools for... 

Herein, an introduction to optimization, aiming to help knowledge development in design optimization techniques is given. Besides, a new method of using the theory of topology optimization to optimize a microgripper system, with a piezoelectric ceramic driver (PZT) microactuator is presented as well. An optimization method is also presented to generate better control conditions. In this study a micro object gripper of 9200 µm length, 8100 µm width, and 500 µm thickness is optimized, and performances improvement is analyzed. This thesis is to investigate best practice and give advice on how to understand the process of topology optimization and how to setup an optimization run. At first, an... 

In the present work, trajectory optimization of the Dual-Arm Cam-Lock robot considering kinematic and dynamic redundancy is performed. First, the optimal control problem is solved only considering kinematic redundancy and then is solved considering dynamic redundancy. General form of the dynamic model for the system is developed using Lagrangian relations. Global optimization method is used for redundancy resolution problem. A performance index is defined based on the consumed kinetic energy and is minimized through a desired trajectory using the global optimization method. Formulations of optimal control problem are derived and initial boundary problem is changed to two point boundary value... 

Non-uniform laminated beams are being used in many engineering applications as primary elements. Helicopter blades, wind turbine blades and robot arms are examples of applications of these structures, in which the high stiffness-to-weight ratio and the non-uniform geometry are of high importance. Changing the thickness in laminated structures is a big challenge in fabrication view as different tapering configurations may significantly alter the stiffness of the structure. Thus, increasing the stiffness and dynamics characteristics of tapered beams with simple configuration is of high importance. The present work aims to investigate the effect of adding nano particles in resin during the... 

The aerial vehicle capable of vertical takeoff and landing (VTOL), have created an interest in the community of researchers and admirers of Unmanned Aerial Vehicles. Among the existing UAV's, those with the capability of vertical takeoff and landing are prominent due to their higher maneuverability and hover capability. Quadrotors mostly have been considered as a flying robot for save and rescue operations in dangerous and unreachable places in addition to its military application. In cross shape of Quadrotor platform on each edge is appointed an electric motor with light rotors that usually are controled by considering motor rates as their only inputs. This thesis aims, to simulate and... 

The main scope of this research is developing an impedance control strategy for a six-degree-of-freedom parallel manipulator with the application in the milling process. One of the most common known parallel manipulators is the Stewart platform, which was proposed in 1965. [It evolved into a popular research topic of robotics in the 1980s.] Problems in various aspects of design, kinematics, dynamics, singularity and workspace analysis have been investigated in the literature. Derivation of control strategies taking advantage of the in-parallel structure or catering for the special problems arising out of that is another important field, whichhas been almost untouched till now.
The main... 

Cooperative systems have been widely studied in literature. The Dual-Arm Cam-Locked (DACL) robot manipulators are reconfigurable arms formed by two parallel cooperative manipulators which operate redundantly but they may lock into each other in specific joints to increase structural stiffness in the cost of losing some degrees of freedom. Obtaining the optimal configuration demands lots of computational time and is not practical in real-time applications. In the present work, considering the kinematics of the manipulator, the optimal control problem of redundancy is formulated in the framework of tasks with the order of priority. The optimal control formulation is derived by using the...