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Binding Energy of Multi-Partite Quantum Systems based on Quantum Thermodynamics Viewpoint
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Rezakhani, Ali (Supervisor)
Abstract
Examining composite quantum systems through quantum thermodynamics, we face the new concept of binding energy. In this thesis, we are going to present a general definition for binding energy in quantum systems which covers any kind of interactions. First of all, we examine the possibility of energy exchange in a quantum system using quantum thermodynamics. In this theory, energy exchanges of an open quantum system may be divided in to two portions: heat and work; due to an accepted definition, heat is the portion of energy that is supposed to change entropy, while work has no influence on that. In this research, we restrict our calculations to the systems which are thermally closed and...
Meson Thermalizationin AdS/CFT Correspondence
, M.Sc. Thesis Sharif University of Technology ; Arfaie, Hesameddin (Supervisor) ; Ali-Akbari, Mohammad (Supervisor)
Abstract
AdS/CFT correspondence is a suitable framework for studying strongly coupled gauge theories. It corresponds a strongly coupled gauge theory to a classical gravity theory with an extra dimension. Quark-gluon plasma which is produced in accelerators is strongly coupled. We use AdS/CFT correspondence to calculate Meson thermalization time by approximating the collisions by a sudden change of baryon number chemical potential. On the gravity side, this is followed with an apparent horizon formation on probe-brane which is the signal of thermalization
Data-Driven Control for a Building Heating System
, M.Sc. Thesis Sharif University of Technology ; Rezaeizadeh, Amin (Supervisor)
Abstract
One of the crucial ways to reduce the energy costs of buildings is to improve the energy efficiency of HVAC systems. Heating, Ventilation, and Air Conditioning (HVAC) refer to the systems used to adjust the heating and cooling within a building. Control of these systems has great importance due to their excessive energy usage. Various control methods have shown a potential for considerable savings in building operation costs. In this research, a Model Predictive Controller (MPC) is applied to perform optimal control actions. MPC opens up numerous opportunities to improve energy efficiency in the operation of HVAC systems because of their capability to consider constraints, prediction of...
High-speed Flow Control Applying Local Heat Addition for Drag Reduction
, M.Sc. Thesis Sharif University of Technology ; Javadi, Khodayar (Supervisor)
Abstract
In this thesis, aerodynamic and aero thermodynamic effects associated with local heat addition into an inviscid steady state high speed flow are studied, numerically. This local heat, can be generated by a C.W laser, has a cylindrical shape and a Gaussian distribution in space. The loctation of the heat source, focal point of the laser, is considered to be upstream of the shock wave generated by a squared obstacle. The free stream Mach is 6 and the angle of attack is zero. Also, the center of this focal point is located on the symmetry line of the square. This kind of heat addition into high speed flow leads to wave drag reduction. Various parameters can affect this kind of flow control....
Machine Learning-Based Building Climate Control Using Weather Forecast Data
, M.Sc. Thesis Sharif University of Technology ; Rezaeizadeh, Amin (Supervisor)
Abstract
Heating, Ventilation and Air-Conditioning (HVAC) systems of buildings consume an excessive amount of energy and emit even more amounts of carbon, all around the world. Rule-Based Control (RBC) algorithms, which switch the facilities on and off according to the measurements of the building’s sensors, are the most frequently utilized controllers in HVAC systems. Due to the conservative settings of the comfort-zone in RBC strategies, energy consumption increases by a large amount. One of the most conventional ways to improve the energy efficiency along with providing the thermal comfort of the occupants of the building, is model predictive control (MPC) algorithms. In order for MPC to work...
Energy Consumption Mitigation in Buildings by Using Seasonal Energy Storage in Aquifers, Heat Pumps and Solar Energy
, Ph.D. Dissertation Sharif University of Technology ; Bahadorinejad, Mehdi (Supervisor) ; Saidi, Mohammad Hassan (Supervisor)
Abstract
The aim of this research has been to modeling and optimization of steam injected gas turbine with inlet air cooling using absorption chiller. The whole system consists of compressor, combustion chamber, turbine, heat recovery steam generator, absorption chiller and cooling coil. The tasks carried out in this research include four points of view. The thermodynamic, exergetic, thermo-economic and environmental points of view are considered along modeling and optimization process. Design variables including temperature of combustion chamber exhausted gas, pinch point temperature of heat recovery steam generator and steam injection flow rate. Finally this modeling and optimization process is...
The Finite Element Modeling of Thermodynamic Contact Problems
,
M.Sc. Thesis
Sharif University of Technology
;
Khoei, Amir Reza
(Supervisor)
Abstract
The numerical modeling of engineering contact problems is one of the most difficult and demanding tasks in computational mechanics. Frictional contact can be observed in many problems; such as: crack propagation, metal forming operation, drilling pile etc. The thermodynamic coupling problems arise naturally in many industrial processes, such as thermal protection structures ,nuclear fuel elements, layerd structures , heat exchanger as well as metal forming. In these situations predicting temperature field as well as the stress field is of considerable applied importance. When two or more bodies are forced to contact whit each other as a result of thermal or/and mechanical load thermodynamic...
Prediction of Homogeneos Charge Compression Ignition (HCCI) Engines Performance Using Multi-Zone Model
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
Some researches have been carried out in the last 20 years in order to increase the present IC engines thermal efficiency and their optimum performance. (HCCI) engine is viewed as a combination of spark-ignition (SI) and compression-ignition (CI) engines. This is because HCCI engines use premixed fuel/air mixture like SI engines and have auto ignition combustion after the mixture is compressed like CI engines. Control of combustion and ignition timing are the main challenges of these engines. Ignition delay, compression ratio, fuel air equivalence ratio and intake temperature and pressure are considered to be the most effective parameters on HCCI combustion.HCCI engines have great potentials...
Comparison of Mechanical Properties of Al-TiB2 Composite in as Cast, Heat Treated and Extruded Condition
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor) ; Davami, Parviz (Supervisor)
Abstract
This research focused on mechanical properties of Al-TiB2 composite in as cast, heat treated and extruded condition. The composites were produced by mixing Al-Ti and Al-B master alloyes. Since some engineering parts during service are supposed to tolerate severe wear conditions, in this research abrasive wear condition was wxamined using pin on disk method. In a fixed load and abrasive disk, composites showed better resistance against wear in comparison with matrix alloy. Furtheremore, T6 heat treatment made composites more resistant against abrasive wear. Finally the best wear resistance was accompolished when composite was extruded and then heat treated. While increase in reinforcement...
Experimental Investigation of Cooling Hot Surfaces By Electrospray
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
The electrospray technique involves the production of small charged droplets through the application of electrohydrodynamic forces. Under well-defined operating conditions, multiple flow modes can be observed, among which the stable jet-cone mode has received significant attention from the research community. This mode is desirable due to its uniform droplet diameter, reduction in droplet rebound when impacting hot surfaces, and potential for utilizing two-phase heat transfer for cooling purposes. In this study, a comprehensive experimental investigation was conducted to evaluate the cooling of hot surfaces through the use of electrospray in the steady cone-jet mode. The fundamental...
Numerical Study of Film Cooling in a Space Thruster
, M.Sc. Thesis Sharif University of Technology ; Mardani, Amir (Supervisor)
Abstract
In high-performance liquid fuel motors and space thrusters, the combustion chamber and nozzle walls are in contact with the gases caused by high temperature and pressure combustion, making severe thermal loads on the walls. Therefore, these systems require cooling mechanisms. The most common way of cooling in space thrusters is film cooling. This study is a numerical simulation of film cooling in the liquid fuel space thrusters. Numerical and empirical studies have been reviewed in this area and evaluated while conducting studies and results to select an appropriate model for ongoing project studies. Along this path, various fuel and oxidizing thrusters, including oxygen and hydrogen,...
Study of Solutions for Skin Temperature Reduction in Process Fired Heaters
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fatholah (Supervisor)
Abstract
Fired heaters are large and complex items used in process plants. Tubular furnaces used mainly in chemical, petrochemical, and refinery process plants. For many process plants, the fired heater performance will determine process unit run-length. High tube metal temperature and coking in the process-fired heaters is one of the serious problems of process plants. Coke forms because the oil in tubes is no longer thermally stable at the operating conditions. Oil film temperature in the inside wall of tube somewhere that, process fluid has highest temperature and lowest velocity. Therefore, process fluid peak film temperature will determined rate of coke formation. This temperature is dependent...
Experimental Study of Internal Forced Convection of Ferrofluid Flow in Magnetizable Porous Media
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor)
Abstract
The use of nanofluids to improve the heat transfer has a special attention in the industry. researches focus on the efficiency of heat transfer nanofluids dates back to 1998. Ferrofluids are a particular type of nanofluids which their nanoparticles have magnetic effect and heat transfer can be increased by applying magnetic field to them. In this work, thermal and hydrodynamic performance of ferromagnetic fluid which flows through a copper tube in thermal entrance region has been studied. The flow in the tube is laminar and is affected by constant heat flux. Part of the tube contains a porous medium with paramagnetic properties and porosity of 0.46. Ferrofluid is composed of F e3O4 and water...
Parametric Study and Numerical Simulation of Spiral Wound Heat Exchanger Performance at Cryogenic Temperatures
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
Cryogenic is the study of physical phenomena at temperatures below 123 Kelvin. One of the applications of cryogenic science is the liquefaction of gases. In the liquefaction cycles of gases, such as helium liquefaction, fluidization occurs in the pressure reducing valve but temperature of the gas should be greatly reduced before it enters the pressure reducing valve. For this purpose, high-performance heat exchangers should be used. Spiral Wound is one of the heat exchangers that has ability to achieve over 90% efficiency due to its structure. Researchs in the field of design and simulation of spiral heat exchangers are limited and are done with a lot of simple assumptions such as constant...
Numerical Study of Heat Transfer Enhancement in Porous Medium by Applying Magnetic Field on Nano Fluid
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, Hani (Supervisor)
Abstract
A 2D simulation has been carried out to study the effect of magnetic field on heat transfer and pressure drop of nanofluid flowing through a pipe filled with porous medium. The nanofluid flow is modeled as a single-phase flow, and Darcy–Brinkman–Forchheimer equation is employed to model fluid flow in porous media. A constant uniform heat flux was imposed on the walls of the cylinder, and the values of Darcy number, Hartmann number, and volume fraction of the nanoparticles were selected as 0.1, 200, and 0.2, respectively. Effects of parameters such as Reynolds number, the material of the porous medium (conductivity and porosity), and material of nanofluids have been investigated in the...
Study of Microstructure and Mechanical Properties of Heat Affected Zone with Gleeble Simulator for Tandem Submerged Arc Welding of X80 HSLA Steel
, Ph.D. Dissertation Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Madaah Hosseini, Hamid Reza (Supervisor)
Abstract
The X80 high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The effects of real and Gleeble simulated double pass thermal cycles on the properties of the heated and reheated coarse grained heat affected zones (CGHAZ) in X80 microalloyed pipeline steel has been investigated. The thermal simulated process for heated region involved heating the X80 steel specimens to the peak temperature of 1400 °C, with different cooling rates. The influence of the second peak temperature during real and simulated welding hass been...
Study of Surface Growth of Organic Thin Film
, M.Sc. Thesis Sharif University of Technology ; Rahimi Tabar, Mohammad Reza (Supervisor)
Abstract
In recent decades the Due to development of coating techniques and the diversity of high organic matter, Discussion of organic coating materials being raised. Moreover, because of many applications of organic thin film in electronic and optical systems for example OTFTs and OLEDs Organic thin film growth topic is very interesting for scientists. Among these, some scientists study the theory and another bunch of scientists pay to practical aspects of this topic. In this thesis I pay to the theoretical level of Organic thin film growth and I simulate the system includes a collection of molecules, Went on to study some statistical properties of the system will be discussed and the dynamic...
Thermodynamic Analysis of a Combined Ejector-assisted System for Electric Equipment Cooling and Air Conditioning in Electric Vehicles
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
Transportation is one of the essential parts of human life and at the same time one of the main sources of greenhouse gases emissions that are harmful to the environment. Therefore, the use of electric vehicles have become widespread in recent years due to limited capacity of natural resources and environmental issues. As a result, attention to climate control systems for electric vehicles and electric aircrafts is growing rapidly. According to multiple studies, the integrated air conditioning-heat pump system is a suitable option as the climate control system.In this research, an air conditioning-heat pump system has been proposed and studied, which works based on the vapor compression...
Experimental Study of Spray Cooling of a Heated Wall
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
With the progression of technology demands for novel method of heat cooling is increased so the old method of cooling such as heat removal by air stream with force convection and even single phase method was not sufficient for today’s industry need. Nowaday, spray cooling method which belongs to two phase cooling method is one of the most popular method. In this study two method of spray cooling: spray cooling with flow blurring nozzle and electrospray cooling were investigated. For both method, at first the physics of phenomena and morphology of spray is studied experimentally then the efficiency of heat removal in each method is evaluated by the assessment of variation of temperature and...
Experimental Study and Modeling of an Organic Rankine Cycle (Orc) Using Low-Temperature Systems
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor) ; Hajilouy Benisi, Ali (Supervisor)
Abstract
Increasing fossil fuel consumption has led to serious problems in energy supply and environmental issues such as global warming, air pollution, ozone depletion, and security issues. A strategy to improve energy consumption requires recycling wasted energy and preventing it from being released into the environment. A wide range of available heat sources such as heat dissipation in the transportation industry, solar heat, biomass and geothermal have low-temperature, which contain large amounts of energy but they do not have enough temperature to make them economically viable and cost-effective. Several applied technologies have been proposed to utilize these resources, among which the organic...