Sharif Digital Repository

The population growth and scarcity of resources such as water and land make the food security as one the most important critical priorities in the world. Development of food production in greenhousesinstead of the traditional agriculture in rural areas is an efficient and applicable approache to reach food security and optimum use of water resources. However, this requires more capital. An important part of this cost is related to the cost of energy supply for heating and cooling in order to provide a suitable condition for the growth of plants. Optimal design of a rural energy supply and optimal operation of existing greenhouses to maximize the benefit of the greenhouse owners and to... 

Urban energy systems are responsible for the majority of the energy consumption around the world and they play an important role in energy issues such as economic security and climate change. Furthermore, there are growing concerns about the depletion of fossil fuel resources and the negative effect they have had on the ecosystem. To this end, a holistic and integrated approach is necessary for the optimal design and operation of urban energy systems that makes expressive betterment in energy efficiency and environmental impact. The aim of this research is to develop an optimum methodology for communities in the context of energy hub. The energy hub is a novel concept to systematically... 

According to the World Bank, nearly 154 billion cubic meters of gas is flared in the world every year. Iran is known as the third gas flaring country by burning about 11.4 bcm (approximately 8% of the total amount). Flared gas is a rich gas and has a high heating value. Therefore flaring it equals to waste of a valuable source of energy. In addition, serious concerns about its environmental effects due to emission of considerable amounts of CO2, SOx, NOx and other pollutants, makes it necessary to find a solution to reduce gas flaring. There are several ways for flared gas utilization including electricity generation, injecting into oil wells for enhanced oil recovery, gas processing and... 

Advancements in smart grid technologies have made it possible for consumers to play an effective role in electricity markets. One of the prominent options for consumers is participating in Demand Response (DR) programs. DR offers incentives designed to induce lower electricity use at times of high market prices or when grid reliability is jeopardized. Large industrial consumers who are potentially capable of directly participating into the wholesale day-ahead electricity markets, can make financial benefits by choosing appropriate strategies to take part in hourly DR programs. As well as participating in DR programs which can be used to manage electricity costs, minimizing electricity... 

The purpose of this project is choosing optimal technologies of cooling and heating and production of usable hot water and also to use optimal thicknesses of heat isolating walls, roof, floor and heat isolating of hot water transfer piping that is done to minimize the expenses of technology, energy and maintenance of the technology. We did all of the above mentioned issues by depicting the energy balance. In this modeling, we first defined four scenarios. Then by using a linear mathematical model of integer, the optimum number of lamps selected in accordance with the standard lighting. In the next step, by using a nonlinear mathematical model, we defined the optimal thicknesses of insulators... 

Upstream Oil and Gas due to the high energy consumption offer multiple degree of freedom that can be exploited to reduce capital and/or operating costs. Be use combination of optimization methods (Retrofit and Operational Problems) due to the complex nature of the optimization in UOG. To achieve the optimization Details need to identify relationships between variables. System modeling based on demand in two categories, can be divided: the demand for water and oil based and model based on electricity demand. Existing and new technologies in both evaluated and identificated the application of the system in upstream sections. The linear programming model used to determine the export of... 

Low effiencies of equipments and lack of forecasting heat integration in some oil regions are the reasons of primary energy losses in these regions. Also there have been difficulties in providing electric power demands in regions separate from the state electricity network which is a barrier in front of exploiting all the potentials of the region. This research introduces a model that can lead to selection of optimal configuration of equipments and units in order to establish a CCHP system that answers variable electric, heating and cooling demands ensuring a safe margin of power generation. The model simultaneously has the ability to select between existing and new installable equipments.... 

The aim of the present research project has been techno-economical analysis of using a CCHP (Combined Cooling Heating and Power) technology at the building of Sharif Energy Research Institute (SERI). The CCHP at SERI is supposed to supply energy required at the building. Useful energy demand at the building include heating in winter, cooling and air conditioning in summer, lighting and power requirement of electric appliance and equipments. Since there are many technologies that could be utilized as CCHP, an optimal model of energy supply system of the building has been developed in order to identify the most appropriate technology. The application of model has enabled techno logical... 

The iron and steel industry has faced several challenges during the recent years. There has always been an aspiration towards higher economic profitability for the system. During the mid 1970s and 1980s the energy crises caused a dramatic rise in energy costs, which led to an increased awareness in energy conservation. In recent years, climate change issues have become more important for the industry. The operating practices for an industrial system are often affected by external restrictions concerning the economical, energy and environmental efficiency of the system. There are a large number of ways to increase the system efficiency, e.g. installation of new process equipment, and practice... 

In most countries Frequency control services as one of the Ancillary services are presented in market scheme. Frequency control are used in different levels to balance generation and demand. Each reserve levels is implemented with specific characteristics and rules. Clearance of energy and one control reserve has some drawbacks so in this thesis we try to clear energy and different reserve levels simultaneously. Each reserve level is determined with special criteria. This criterion in primary reserve is frequency deviation restriction and unit commitment risk in territory reserve that is determined by system operator. In this thesis these two criteria are formulated in linear form and... 

In this study, the nonlinear modeling of insect-like flapping-wing was investigated as a multi-body system using the Newton-Euler method. This modeling, in addition to aerodynamic effects, has specifically addressed the effect of mass and inertia of the wings in the equations on the dynamics of the system. Then, by transforming the equations into a state-space form, a model reference adaptive controller was designed with Lyapunov stability proof. This controller enables optimal control performance in the face of variations caused by the uncertainty of the flapping-wing parameters, considering the fast dynamics of the control actuators and introducing an optimally linearized reference system.... 

The purpose of this thesis is to design and implement a controller for a Ducted-Fan in the landing and take-off phase using a linear quadratic tuning method based on differential game theory. This is a control method with a robust control approach and tries to see all the disturbances and unmodulated dynamics in the form of the second actor and produce a control command according to the worst behavior of the second actor. For this purpose, 6 DOF Ducted-Fan have been modeled. then The proposed controller is designed for a linearized model around the hover point. In the next step, the performance of the proposed controller is compared with the SlidingMode Controller. Also, the parameters of... 

In this research, with the help of a comprehensive dynamic model, the stability, control, dynamics and twisting of airships with flexible bodies and beams have been investigated. For the first time, the influence of the twisting mode of the body on the dynamic behavior and control of the airship has been investigated by considering the pressure drop inside the body. By obtaining the terms of kinetic energy and the potential of the body and beams, the governing equations of the bird have been extracted and with the help of mass integrals, the velocity of the body and beams has been obtained. The answer to this non-linear dynamic couple problem, due to the existence of two types of dynamic... 

In the present study, the numerical simulation of 2D inviscid compressible cavitation flow is performed by using the compact finite-difference method. The problem formulation is based on the multiphase compressible Euler equations with the assumption of the homogeneous equilibrium model and the system of baseline differential equations is comprised of the continuity, momentum and energy equations for the vapor-liquid mixture. To complete the system of governing equations, the ideal gas relation is used for the vapor phase and the Tait relation is applied for the liquid phase, and therefore, the compressibility effects are considered for both the vapor and liquid phases. To analyze the flow... 

In this research, the dynamics, aero-elasticity, and control of an airship with a flexible body hull and fins are investigated. The flexible airship is modeled as a combination of several beams with specific boundary conditions. So that the dynamics and vibration of its body hull and fins can be taken into account regarding the aerodynamic, gravity, aerostatic, and control input forces. The governing equations of motion of the system are derived by using the velocity of an arbitrary point on each component and integration over the component and substituting them into the Euler-Lagrange equations in a body frame. Afterward, the added mass acting on the hull is calculated. Then, a perturbation... 

Accurate and fast attitude estimation of a rigid body plays an essential role in the performance of a vehicle’s control system, especially aerospace vehicles. Ample works have been done to increase the accuracy and speed of the attitude estimation process, but all have been developed according to a model-based approach. This approach assumes that the torques acting on the body have a known dynamical model that is used for the attitude estimation. The purpose of the present research is to estimate the attitude via a model-free approach, i. e. dynamics of the torques acting on the body are no longer assumed to be known, and its learning is the next step. Thus, the problem formulation of this... 

It is difficult and time-consuming to calculate the reaction rate directly. For turbulence modeling methods such as RANS or LES, various statistical methods are used to model turbulence-kinetics interactions. The purpose of this study is to implement the linear eddy model in CANTERA open source-code. This code instantly simulates one-dimensional, quasi-one-dimensional laminar flames with different chemical kinetics in which the effects of viscosity and molecular diffusion are implemented like a laminar flame. The effects of turbulence are simulated by a series of stochastic processes called triple maps. This research can provide a linear eddy model in different types of one-dimensional... 

As the aeronautical design evolves, the optimal solutions tend to employ slenderer and aeroelastic wings. These slender wings could help to increase the flight endurance, by decreasing the fuel consumption. However, as a wing becomes slenderer its structural stiffness decreases. The decrease in the stiffness highlights the structural vibrations and aeroelastic behavior in these wings. Atmospheric turbulences induce vibrations that can cause fatigue and structural failures. A possible solution to decrease these oscillations is to use active vibration control and flutter suppression. Conventional control surfaces on a wing can be used to implement the active vibration control. However, given... 

The goal of this thesis is modeling and simulation of aircraft landing motion in order to evaluate the performance of an optimal anti-skid brake system (ABS) for the main landing gears with friction effects. In this process, the aircraft 6DOF perturbed equations of motion augmented with pertinent friction and brake forces and moments have been utilized. Subsequently, the problem is formulated within the framework of an optimal LQR that has allowed for generation of control brake commands as well as aircraft landing performance at different landing conditions with and without the proposed ABS. The results demonstrate the proposed ABS has been effective in providing admissible landing... 

The subject of this study is design of a linear quadratic Gaussian controller based on identification of dynamic behavior of unmanned model helicopter “Raptor” in its hover flight. To achieve this end, first, the helicopter linear transfer functions are identified with frequency response method by applying specific inputs to the model of Raptor in the X-Plane software and receiving system outputs via Simulink. Next, using the identified dynamic model of the helicopter, an optimum linear controller is designed for hover flight. As an optimum linear controller needs all the state variables, a Kalman filter is utilized to estimate them, using outputs of various sonsors such as GPS and gyro....