Sharif Digital Repository

In this project dynamic effect of changes in gas turbine load on power plant, reforming and Co2 capture section is investigate. The reason for study of effects change of gas turbine load is that gas turbine determines the performance of the other parts in combined cycle including gas cycle and change of gas turbine load can alter the load and the performance of other parts in the power plant and in other process such as production of synthesis gas and carbon dioxide separation unit. One Autothermal reactor and eight sewgs reactor are utilized to produce gas turbine fuel which is mainly consist of Hydrogen. this part of thesis is to be implemented in the gPROMS from process system enterprise... 

Making distribution networks smart includes all appropriate hardware and software devices for controlling and making operation of the network optimized. (SCADA system, distribution management, communication equipments, substation automation, monitoring equipments, etc). Monitoring and management of electricity distribution networks enable us to control and record events in the operation. Equipments in the distribution substations, will be under full time monitoring and hence, we would be able to protect them against over loads, over voltages, load unbalances and inefficient usage of transformers capacity and other distribution instruments. It also enables us to manage operation switchings,... 

In this thesis, a dynamic model of the biomimetic robotic fish with a flexible tail is developed. In this model, the oscillating frequency of the tail controls the forward velocity, and the body spline offset parameter controls the heading angle. The robotic fish were divided to two parts: a rigid body, and a flexible tail. The rigid body includes the head and the electrical and mechanical equipment. The bond graph model was developed and the numerical values were extracted from constructed robotic fish have also been hydrodynamically analyzed. Simulation results were quantitatively compared and verified with Matlab Simmechanics simulations. These simulations described the lateral movement... 

A complete 6DOF flight dynamic model of an elastic flapping wing (EFW), integrated with unsteady aerodynamic theory is developed. In this respect, initially efficient high fidelity modules for EFW structural dynamics (SD) as well as unsteady aerodynamics loadings (UAL) to be coupled with its flight dynamics are prepared. A modal approach is followed to model structural dynamics of plain and 3D EFWs. This is in contrast with the Euler-Bernoulli beam theory that is mostly utilized for SD in the existing literature. In addition, due to the possibility of large wing deformations as well as the existence of non-linear displacement regime for realistic EFW flights, non-linear modal approaches such... 

In recent years, the seat suspension system in commercial vehicles, industry, agriculture, transportation and … have been focused by researchers. Designing the spring-damper isolators for vehicle’s seat can be an achievable and suitable strategy to increase the comfort and decrease the risk of injuries in vehicles. In this research, the effect of vibrations due to road roughness has been examined by dynamic modeling of a vehicle in combination with the human body model. Thus by using spring-damper isolators and genetic algorithm, we try to optimize the performance of the system. Designing parameters includes the stiffness and viscosity of seat isolator and our target functions include the... 

In recent years, unmanned vehicles have intensively been developed to reduce human dangers for marine applications. Predicting the hydrodynamic coefficients of an autonomous underwater vehicle is important during the vehicle’s design phase. In other words to design an AUV, one must clarify its maneuverability and controllability based on a mathematical model. The mathematical model contains various hydrodynamic forces and moments expressed collectively in terms of hydrodynamic coefficients. Therefore, the correct values of the coefficients must be known to precisely design the controller of AUVs. SUT-2 is an AUV, being developed by Marine Engineering Laboratory of Sharif University of... 

Utilization of the rod fastened rotors in gas turbines as well as induction motors increased recently due to several advantages. Rods in rod fastened rotors are connected to shafts in both sides of the rotors and pre-tightened using bolts in each ends. Predictions of dynamic characteristics of these rotors have specific complications as a result of effects of contact interfaces raised due to applied pre-tightening load. Studies carried out in the field of vibration analysis of rotors consist of investigation of vibration of shafts, bearings and other connected components to the rotors. One of the best methods for modeling and analyzing complicated structures such as rod fastened rotors is... 

The necessity of electrical energy, high cost of big power plants and high voltage transmission lines and also progressing of restructuring science has lead to the increasing of tendency to use the distributed generation in electrical industry. Among of different types of distributed generations, fuel cell power plants because of many advantages such as high efficiency, low emission, modular structure and ect., have a high potential to be used in power systems. The fuel cells produce electrical energy by chemical reactions. Due to the necessity of having the knowledge related to the chemical reaction which are effective on fuel cell, to study the fuel cell performance, this type of... 

The main popuse of this Thesis is investigating of the different wagon arrangement effect on stability of the train set. So to gain this goal, one train with 10 wagons has been simulated. The model of the each wagon is Nonlinear with 40 DOF. 3 of the wagons are heavy and make 3 different kinds of arrangement by putting them at first, middle and the end of the train (HLL, LHL and LLH arrangements). Then these three arrangements have been simulated on two differen tracks and conditions, 1st Accelerating on curved track (320 R) with positive slope and 2nd decelerating on curved track with negative slope.We suppose that the contact is singular point and aslso contact equations have bben solved... 

Fluid flow simulation in heterogeneous, full field porous media, like hydrocarbon reservoirs and underground aquifers usually requires multimillion block models, demanding unpractical computation times. Massive researches have been conducted to upscale these fine grid models to coarse models with manageable block numbers. Many upscaling methods have been proposed. These methods differs regarding their gridding techniques (uniform/ structured or disordered), general applicability (process dependency), maximum coursing level achievable, accuracy of the method and their speed-up factor and extend from simple arithmetic averaging to complicated numerical methods. Applying a very powerful... 

Two phase flow through porous media is one of great interests which have been studied for decades in petroleum sciences and even other fields, e.g. hydrology and physics, to solve problems such as enhanced oil recovery, contaminated groundwater or CO2 sequestration projects. Flow in porous media typically predict by means of Darcy’ law which in two phase flow lead to equations such as Buckley-Leverett or Koval, but today it is well approved that compact prediction of flow pattern by these equations may be accompanied by enormous errors and it’s because flow in certain condition is fractal. In this work a new mechanistic model has been used for simulating of immiscible drainage process and... 

In this project, a processing algorithm is approached which is resistant against environmental and motion noises to find the pulse transmission time using two photoplethysmography signals. For this purpose, a new processing framework is checked and generalized for photoplethysmography signals. Already, this processing framework had impressive results. The considered processing method is obtained by offering a dynamic model for the signal and using it in a Kalman filter structure. For the photoplethysmography signals, with modeling every beat of signal to a Gaussian three or four sum form and with adding self-returned equations for model parameters, a nonlinear signal model is obtained. Then,... 

One of the most surprising lessons of dynamical systems theory is that the phase spaces of simple nonlinear systems may contain strange attractors. For certain simple systems, such as pendulum, direct observations of the phase space and finding strange attractors are possible. But physical systems in which all the relevant dynamical variables can be simultaneously monitored are relatively scarce. Takens’ theory shows how a time-series of measurements of a single observable state can be often used to reconstruct qualitative features of the phase space of the system. In this research, using the time-series of one measurable state, an algorithm is proposed to control chaos. The approach... 

Control of a group of autonomous surface vessels with realistic dynamic for circling mission is distributed with the aid of Lyaponov and graph theory. in this brief, to obtain a cooperative controller, new coordination transfer are presented and graph theory is used to illustrate the communication between the agents. With the aid of Lyaponov theory and graph application, Decentralized and scalable controllers are designed for group of autonomous vessels to converge to desired geometry to circling a specific target. Because of the realistic dynamics, Non-Holonmic dynamics and turning constrains of the vessels are considered in the design process. The advantage of proposed controller is: it... 

Nowadays, nano-positioners play an important role in advanced technologies, such as atomic force microscopy, genetic manipulation, nano-metrology, nano-fabrication, semi-conductors and etc.In this paper, a dynamical model has been derived for a nano-positioner. This nanopositioner was designed and fabricated in Sharif university of technology. In this paper the mentioned mechanism has been considered as a planar mechanism. First, a finite element model has been developed in Comsol multi-physics software. This model was used as the reference model in the next steps. Afterward, a 10 degrees of freedom model was proposed to estimate the Comsol model. The mass, stiffness, as well as damping... 

This research aims to study the identification of inertia parameters (IPs) of space-robots with the main focus on Active Space-Debris Removal (ASDR) application. In many future space missions, like ASDR, the spacecraft should handle objects (like debris) with unknown IPs. To control and stabilize the spacecraft, it is crucial to identify the dynamic model of the spacecraft in such these missions. On the other hand, uncertainties in the IPs of spacecraft (including space-manipulator) make the identification problem more complex. To overcome the complexities related to mathematical representation of identification equation, a new mathematical tool called Matrix-Set is proposed to develop the... 

According to high nominal pressure and controllable flow, variable displacement axial piston pumps are used widely in hydraulic industry. However, there still exist many problems and limitations in the areas of design, controllers and performance. To solve the problems without wasting time and money in making prototypes, an accurate dynamic model of the pump is required which predicts pump behavior under various control signals and loads. The lack of simple and practical methods of measuring describing parameters of pump dynamics, makes investigation and verification of such a model very challenging. In this thesis, literature review is presented in a wide range. After investigating of... 

In present research, a new system of energy extraction from water flow has been studied and optimized. This semi-active energy harvesting system consists of an airfoil that is connected to the generator by an arm. The passage of water causes the airfoil to move, so the hydrodynamic forces on the airfoil will cause the arm to move and finally the generator. In this research, complete dynamic modeling of this energy extraction system including generator, airfoil, controller and actuator modeling is presented and the governing dynamic equations are extracted using this modeling for dynamic simulation. Two dimensional fluid simulations have also been performed using fluent software. Finally, in... 

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... 

The mud loss and its impact on the formation play a vital role in the productivity of the formation and the near wellbore area. Despite the importance of the use of mud during the drilling process, one cannot overlook the issues that may be caused by losing mud into the formation. In addition to the formation damage caused by mud loss, the cost associated with such phenomenon and drilling operational issues and challenges has motivated the industry to look into different avenues to resolve the mud loss issue or reduce its impact. Evaluating the impact of such a phenomenon on these issues requires accurate modeling. In this study different models have been developed to evaluate the impact of...