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    Design and optimization of a heat driven thermoacoustic refrigerator

    , Article Applied Thermal Engineering ; Volume 62, Issue 2 , 25 January 2014 , Pages 653–661 Ghorbanian, K ; Karimi, M ; Sharif University of Technology
    Abstract
    The present paper deals with the design and optimization of a heat driven thermoacoustic refrigerator. A simplified model is developed which enables to pinpoint and examine the most important physical characteristics of a compact traveling wave thermoacoustic refrigerator driven by a traveling wave thermoacoustic engine. The model can explain the so-called traveling standing wave effect in thermoacoustics very well. The position, length and hydraulic radius of the refrigerator are optimized for the maximum total COP. The prime mover efficiency, refrigerator COP and dimensionless dissipation and their impacts on total COP are investigated and discussed. The results indicate that a COP of... 

    Design and optimization of a heat driven thermoacoustic refrigerator

    , Article Applied Thermal Engineering ; Volume 61, Issue 2 , 2013 , Pages 653-661 ; 13594311 (ISSN) Ghorbanian, K ; Karimi, M ; Sharif University of Technology
    2013
    Abstract
    The present paper deals with the design and optimization of a heat driven thermoacoustic refrigerator. A simplified model is developed which enables to pinpoint and examine the most important physical characteristics of a compact traveling wave thermoacoustic refrigerator driven by a traveling wave thermoacoustic engine. The model can explain the so-called traveling standing wave effect in thermoacoustics very well. The position, length and hydraulic radius of the refrigerator are optimized for the maximum total COP. The prime mover efficiency, refrigerator COP and dimensionless dissipation and their impacts on total COP are investigated and discussed. The results indicate that a COP of... 

    Fast iterative reconstruction algorithm for microwave-induced thermoacoustic imaging

    , Article 12th IEEE Biomedical Circuits and Systems Conference, BioCAS 2016, 17 October 2016 through 19 October 2016 ; 2017 , Pages 1-4 ; 9781509029594 (ISBN) Nan, H ; Allahgholizadeh Haghi, B ; Aliroteh, M. S ; Fallahpour, M ; Arbabian, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Abstract
    In this paper we propose a fast iterative reconstruction algorithm for microwave-induced thermoacoustic (TA) imaging. Instead of calculating the forward and back projections in real time, we construct a library of the impulse responses of individual pixels in advance. During reconstruction, only covariance calculations are performed to reconstruct the intensity of each pixel. In addition, we propose to use a Wiener filter based-deconvolution to accelerate convergence, enabling even single iteration construction in some scenarios. We validate the proposed method both with simulations as well as experiments. Compared to the time reversal method, the proposed fast iterative reconstruction... 

    Design and Construction of the Coupled Thermoacoustic Refrigerator

    , M.Sc. Thesis Sharif University of Technology Fazli, Mahyar (Author) ; Soltani, Mohammad Reza (Supervisor) ; Karimi, Mohsen (Co-Advisor)
    Abstract
    One of the significant as well as fascinating utilization of thermoacoustic is combining heat pump and thermoacoustic refrigerator. By means of supplied heat from hear source, the heat pump generates acoustic power which will be absorbed by refrigerator and forwarded to the heat source afterwards. In other words, thermoacoustic systems, from the side of which heat is absorbed, produces chill in the opposite side. Due to the novelty as well as heavy and precise research requirements, these systems has been neither designed nor manufactured in our country yet. In this research a laboratory prototype from aforementioned systems has been constructed, thereby paving the way for enjoying and... 

    Exergy analysis of an integrated gas turbine thermoacoustic engine

    , Article ASME 2010 4th International Conference on Energy Sustainability, ES 2010, 17 May 2010 through 22 May 2010, Phoenix, AZ ; Volume 1 , 2010 , Pages 945-951 ; 9780791843949 (ISBN) Ghorbanian, K ; Karimi, M ; Sharif University of Technology
    2010
    Abstract
    An attempt is made to utilize exhaust gases of a small gas turbine in augmenting power output through the employment of a thermoacoustic system. It is assumed that the thermoacoustic system is powered only by the waste heat of the gas turbine. A comprehensive cycle analysis of the integrated gas turbine thermoacoustic engine "IGTTE" is carried out from energy and exergy point of view. Results indicate the thermodynamic advantages of the IGTTE  

    Design and optimization of a cascade thermoacoustic Stirling engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy ; Volume 227, Issue 7 , September , 2013 , Pages 814-824 ; 09576509 (ISSN) Karimi, M ; Ghorbanian, K ; Sharif University of Technology
    Professional Engineering Publishing  2013
    Abstract
    This article deals with the design and optimization of a cascade thermoacoustic Stirling engine. Different configurations for cascade thermoacoustic Stirling heat engine are investigated. A simplified model is proposed to enable initial design guidelines. The most important characteristics of the cascade system are examined. The results indicate that the thermoacoustic engines in cascade configuration may achieve very low onset temperatures. A suitable configuration is selected and the locations and dimensions of different thermoacoustic units are optimized to achieve low onset temperatures as well as high values for the acoustic power output and efficiency. The results support the... 

    Numerical Study of Streaming in Thermal Buffer Tube

    , M.Sc. Thesis Sharif University of Technology Bahrami, Mohsen (Author) ; Ghorbanian, Kaveh (Supervisor)
    Abstract
    Streaming has some applications in medical and industrial science. This phenomena can increase or decrease efficiency of an acoustic system. Deliberate streaming used to eliminate heat exchanger is an example of desired applications. In the most cases, secondary flow is an undesired issue. Streaming in thermal buffer tube (TBT) of thermoacoustic stirling heat engine (TASHE) has some unwanted effects. The main goal of author is to simulate numerically periodic field in TBT with axisymmetric geometry and study the effects of variating geometry and turbulence on the intensity of streaming. According to inaccessible boundary conditions in TBT of TASHE, firstly, the field is numerically solved... 

    Design of a Thermoacoustic Refrigerator Based on the Airport Noise Absorption

    , M.Sc. Thesis Sharif University of Technology Basiri, Moein (Author) ; Soltani, Mohammad Reza (Supervisor)
    Abstract
    In the last few decades, the consumption of fossil fuels and its increasing worldwide price on one hand, and the severity of global warming on the other hand have led researchers and engineers to invent and expand new cooling technologies. Cooling has the largest portion of energy consumption of households during the hot season of a year. In addition to high energy consumption, the common cooling systems utilize gases which are harmful for environment. Thermoacoustics is a new and recent technology which has arised from combination of acoustics and thermodynamics. In Iran, research in this new field was pioneered by Ghorbanian in Department of Aerospace Engineering at Sharif University of... 

    Experimental and Theoritical Study of Thermo-acoustic Effect in Carbon Nanotubes

    , M.Sc. Thesis Sharif University of Technology Asadzadeh, Saeed (Author) ; Moosavi, Ali (Supervisor)
    Abstract
    Carbon Nanotube webs exhibit interesting properties when used as thermo-acoustic projectors. This work studies thermo-acoustic phenomena of these sound sources both in near and far field regions. Our three-dimensional simulation and experimental data show pressure waves are highly affected by dimensions of sound sources in near field due to interference effects. Although pressure amplitude increases with increasing frequencies, maximum pressure amplitude reached in lower frequencies may become larger than its maximum amount at higher frequencies because of interference effects. Measurement of different surface area sources shows generation of sound waves in far field is independent of... 

    Thermodynamic analysis of a hybrid gas turbine/thermoacoustic heat pump/refrigeration engine

    , Article International Journal of Exergy ; Volume 15, Issue 2 , 1 November , 2014 , Pages 152-170 ; ISSN: 17428297 Ghorbanian, K ; Karimi, M ; Sharif University of Technology
    Abstract
    Possible performance enhancement of small gas turbine power plants through the application of thermoacoustic systems is examined. The thermoacoustic subsystem is powered only by the waste heat of the gas turbine. Two different gas turbine configurations are considered: a Thermoacoustic refrigerator assisted gas turbine (TRG) and a Combined thermoacoustic heat pump and refrigeration assisted gas turbine (CTHRG). Exergy, rational efficiency and relative power gain (RPG) of these configurations are compared with those from the recuperated gas turbine engine. The results indicate that the integration of thermoacoustic system to a simple gas turbine cycle will not only enhance the energy/exergy... 

    Acousto-refrigerator with an adjustable mechanical resonator

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 2 , 2008 , Pages 183-196 ; 1728-144X (ISSN) Amjadi, A ; Abolhassani, M. R ; Jafari, S. B ; Sharif University of Technology
    Materials and Energy Research Center  2008
    Abstract
    Thermoacoustics describes energy conversion processes, activated by interaction temperature oscillation, accompanying the pressure oscillation in a sound wave, with solid boundaries. In ordinary experience this interaction of sound and heat cannot be observed, because of the very low temperature differences, but under suitable conditions, it can be emphasized and amplified to create remarkable thermodynamic effects such as, steep thermal gradients, powerful convective heat fluxes, and strong sound fields. We designed and constructed a simple thermoacoustic refrigerator with an adjustable mechanical resonator, coupled with the acoustic resonator. Our experimental data showed about % 10... 

    Energy and exergy analyses of an integrated gas turbine thermoacoustic engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy ; Volume 225, Issue 4 , June , 2011 , Pages 389-402 ; 09576509 (ISSN) Karimi, M ; Ghorbanian, K ; Gholamrezaei, M ; Sharif University of Technology
    2011
    Abstract
    In this article, an attempt is made to utilize the exhaust gases of a small gas turbine to augment power output through the employment of a thermoacoustic system. A simple gas turbine cycle is selected as the base cycle and it is assumed that the thermoacoustic system is powered only by the waste heat of the base gas turbine. A comprehensive cycle analysis of the integrated gas turbine thermoacoustic engine (IGTTE) is carried out from an energy and exergy point of view. Exergy efficiency and internal exergy efficiency are calculated for the different components of the base gas turbine engine as well as the IGTTE. Value and exergy flow diagrams are used to investigate the possible... 

    Design and Optimization of Looped Thermo-acoustic Engine

    , M.Sc. Thesis Sharif University of Technology Mohammadi Gharagozlou, Neda (Author) ; Soltani, Mohammad Reza (Supervisor) ; Karimi, Mohsen ($item.subfieldsMap.e)
    Abstract
    Thermo-acoustic sience is the conversion of heat to power through the sound wave. Thermoacoustic engines for different reasons like easy making, not having moving parts and so high reliablibility of system is in attention for researchers. Also looped-tube thermoacoustic engines are very new in the world and sience and thechnology of them belong to a few companies and for different reasons are replacing different kinds of thermoacoustic engines.They have higher efficiency than other types. They can be made in large scales. They have a larger thermal range. In this research, the numerical study of one, two and four stage looped-tube thermoacoustic engines has investigated with the help of... 

    Dynamic behavior Analysis of a Swirl Burner using Recurrence Plotting Method

    , M.Sc. Thesis Sharif University of Technology Talebi, Mohammad Sadegh (Author) ; Farshchi, Mohammad (Supervisor)
    Abstract
    In this dissertation, based on the method of recurrence plot and its application in dynamic system analysis we examine the behavior and dynamic analysis of a swirl burner. Though retrospective studies on thermoacoustic instability have been performed on single-blown premixed cone shape flames and several combustion systems but so far this method has not been considered for a real combustion system. There have also been more work on phenomena known as the flame separation from the burner (blowout) and its propagation into the burner (flashback), which is almost conscious of their process. In fact, selecting a single flame has been to eliminate the flame-flame interactions in the... 

    Experimental Investigation of Streaming in a Thermoacoustic Engine

    , M.Sc. Thesis Sharif University of Technology Jebraeili, Pouya (Author) ; Ghorbanian, Kaveh (Supervisor)
    Abstract
    Streaming is a phenomenon that is driven by acoustic oscillations and leads to the reduction of efficiency in thermoacoustic engines. Acoustic streaming induced by acoustic oscillations is a steady mass-flux of second order and can cause heat leak that greatly reduces efficiency. There are two types of streaming in thermoacoustic engines; Gedeon streaming and Rayleigh streaming. Gedeon streaming exists within the porous media and Rayleigh streaming occurs in the thermal buffer tube. Thermal buffer tube separates the hot heat exchanger from secondary cold heat exchanger. In this thesis, experimental study of Gedeon streaming and Rayleigh streaming has been accomplished by temperature... 

    Numerical Analysis of Underwater and Within Air Sound Generation by using Carbon Nanotube

    , M.Sc. Thesis Sharif University of Technology Saleki, Omid (Author) ; Moosavi, Ali (Supervisor)
    Abstract
    Carbon nanotubes have special thermodynamic properties which makes suitable as a thermo-acoustic sound source. Recently it is shown that by using these nanotubes it is possible to generate strog sound waves in air or water. Experimental analysis of phenomenon can be complicated and expensive. Hence this fact, in this study using molecular dynamic simulation, numerical analysis of sound generation with CNTs in air and water is discussed. For this purpose, the required structue of the system is generated and it has reaced equilibrium. This process has been done for 6 different CNT and for each CNT there are 5 different distances between them. Althogether, 30 different cases has is used for... 

    Performance Analysis of Thermoacoustic Prime Mover

    , M.Sc. Thesis Sharif University of Technology Sadeghizadeh, Zahra (Author) ; Ghorbanian, Kaveh (Supervisor)
    Abstract
    Traveling wave thermoacoustic prime mover is studied in this project. For this purpose, based on one dimensional thermoacoustic equations, thermoacoustic flow is modeled in each segment of thermoacoustic systems. Since regenerator is the most important segment in a traveling wave thermoacoustic prime mover, modeling of the flow in regenerator is considered as the primary motivation for this research. In order to model the thermoacoustic engines, governing 1D relations are simplified and developed. Moreover, to solve equations in regenerator, tortuous geometry of regenerator is approximated with the stack consisting of circular pores. Therefore, in this research stack relations has been used... 

    Numerical Investigation of Jet Pump Performance in Traveling Wave Thermoacoustic Engine

    , M.Sc. Thesis Sharif University of Technology Barzegari, Ali (Author) ; Ghorbanian, Kaveh (Supervisor)
    Abstract
    Thermoacoustic engines are a promising alternative to the conventional heat engines due to the absence of moving parts in the hot region and the small temperature difference required for operation. However, the traveling wave thermoacoustic engine configuration has a relatively lower efficiency due to a phenomenon called Gedeon streaming. In this regard, a jet pump might be used to lower the negative effects of Gedeon streaming. The jet pump, which is simply an element consisting of one or more tapered holes, induces an oscillating flow through the asymmetric device and hence resulting in a time-averaged pressure drop across it. As a result, by balancing this time averaged pressure drop with... 

    Low swirl premixed methane-air flame dynamics under acoustic excitations

    , Article Physics of Fluids ; Volume 31, Issue 9 , 2019 ; 10706631 (ISSN) Shahsavari, M ; Farshchi, M ; Chakravarthy, S. R ; Chakraborty, A ; Aravind, I. B ; Wang, B ; Sharif University of Technology
    American Institute of Physics Inc  2019
    Abstract
    In this study, simultaneous particle image velocimetry and planar laser induced fluorescence of hydroxyl radical, chemiluminescence imaging, and hot-wire measurements are utilized to study reacting low swirl flow dynamics under low to high amplitude acoustic excitations. Results show that a temporal weak recirculation zone exists downstream of the flame, which is enlarged in size under acoustic excitations. Investigations show that temporal behaviors of this recirculation zone play a significant role in flame movements and instabilities. As the acoustic wave amplitude increases, the flame lift-off distance changes drastically, resulting in flame instabilities (flashback and blowout) during... 

    Optomechanical heat transfer between molecules in a nanoplasmonic cavity

    , Article Physical Review A ; Volume 100, Issue 1 , 2019 ; 24699926 (ISSN) Ashrafi, S. M ; Malekfar, R ; Bahrampour, A. R ; Feist, J ; Sharif University of Technology
    American Physical Society  2019
    Abstract
    We explore whether localized surface plasmon polariton modes can transfer heat between molecules placed in the hot spot of a nanoplasmonic cavity through optomechanical interaction with the molecular vibrations. We demonstrate that external driving of the plasmon resonance indeed induces an effective molecule-molecule interaction corresponding to a heat transfer mechanism that can even be more effective in cooling the hotter molecule than its heating due to the vibrational pumping by the plasmon. This mechanism allows us to actively control the rate of heat flow between molecules through the intensity and frequency of the driving laser. © 2019 American Physical Society