Loading...
Search for: heat-transfer
0.006 seconds
Total 636 records

    Can Thermodynamic behavior of Alice’s particle affect bob’s particle?

    , Article Scientific Reports ; Volume 10, Issue 1 , 2020 Soltanmanesh, A ; Naeij, H. R ; Shafiee, A ; Sharif University of Technology
    Nature Research  2020
    Abstract
    We propose an experiment to investigate the possibility of long-distance thermodynamic relationships between two entangled particles. We consider a pair of spin-12 particles prepared in an entangled singlet state in which one particle is sent to Alice and the other to her distant mate Bob, who are spatially separated. Our proposed experiment consists of three different setups: First, both particles are coupled to two heat baths with various temperatures. In the second setup, only Alice’s particle is coupled to a heat bath and finally, in the last setup, only Bob’s particle is coupled to a heat bath. We study the evolution of an open quantum system using the first law of thermodynamics based... 

    Effect of vortex flow on heat transfer to combustion chamber wall

    , Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE 2004, Anaheim, CA, 13 November 2004 through 19 November 2004 ; 2004 , Pages 37-44 ; 079184708X (ISBN); 9780791847084 (ISBN) Jahangirian, S ; Ghafourian, A ; Abarham, M ; Saidi, M. H ; Sharif University of Technology
    American Society of Mechanical Engineers  2004
    Abstract
    A new experimental facility was designed, fabricated and tested to model and study the effect of bidirectional swirl flow on the rate of heat transfer to combustion chamber walls in many applications. Heat transfer to combustion chamber walls is an unwanted phenomenon. Reduction of this heat transfer can result in time and cost saving methods in design and fabrication of combustion chambers. The experimental study was performed by using propane and air with oxygen as fuel and oxidizer respectively. The location of injection ports and geometry of combustion chamber are flexible and could be varied. Tests were performed with different mass flow rates of fuel and oxidizer. For the same flow... 

    Heat transfer enhancement in shell-and-tube heat exchangers using porous media

    , Article Heat Transfer Engineering ; Volume 36, Issue 3 , 2015 , Pages 262-277 ; 01457632 (ISSN) Esmaeili Rad, S ; Afshin, H ; Farhanieh, B ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Abstract
    A numerical simulation has been carried out to investigate the heat transfer enhancement in a shell-and-tube heat exchanger using a porous medium inside its shell and tubes, separately. A three-dimensional geometry with k-ε turbulent model is used to predict the heat transfer and pressure drop characteristics of the flow. The effects of porosity and dimensions of these media on the heat exchanger's thermal performance and pressure drop are analyzed. Inside the shell, the entire tube bundle is wrapped by the porous medium, whereas inside the tubes the porous media are located in two different ways: (1) at the center of the tubes, and (2) attached to the inner wall of the tubes. The results... 

    Tube bundle heat and mass transfer characteristics in falling film absorption generators

    , Article International Communications in Heat and Mass Transfer ; Volume 30, Issue 4 , 2003 , Pages 565-576 ; 07351933 (ISSN) Jani, S ; Saidi, M. H ; Mozaffari, A. A ; Sharif University of Technology
    2003
    Abstract
    Falling film heat and mass transfer analysis of a horizontal tube bundle in a generator of absorption chillers have been studied. The film Reynolds number is limited to the laminar flow and the effect of ripple on the free surface has been ignored. Thermal boundary conditions are considered to be constant wall temperature and desorption is considered to be free surface evaporation. Analysis is based on a single column of horizontal tubes, arranged in a vertically spaced configuration. A comprehensive numerical code has been developed to solved the governing equations. The functional relationship of average heat transfer coefficient of tube bundle has been analytically correlated to the first... 

    Experimental Investigation of Nano Particle Effect on Heat Transfer in a Micro Heat Exchanger

    , M.Sc. Thesis Sharif University of Technology Jafarpoor Chekab, Hamideh (Author) ; Shafii, Mohammad Behshad (Supervisor) ; Saidi, Mohammad Hassan (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    Modern microelectronic systems generate a large amount of heat which must be transferred out of the system without excessive temperature rise. Conventional forced air convection and microchannel cooling plates have reached their performance limits Nanofiuids are proposed as an innovative way to solve the problem. A nanofiuid is nanoscale solid particles dispersed in a traditional heat transfer liquid. Some studies show an anomalous increase in the thermal conductivity for stationary nanofiuids. However, there are only few previous studies on the convection heat transfer rate and viscosity of nanofiuids. Both convection and stationary measurements of the thermal conductivity are widely... 

    Electrohydrodynamically enhanced nucleation phenomenon: A theoretical study

    , Article Journal of Enhanced Heat Transfer ; Volume 15, Issue 1 , 2008 , Pages 1-15 ; 10655131 (ISSN) Moradian, A ; Saidi, M. H ; Sharif University of Technology
    2008
    Abstract
    Chaotic behavior of bubbles and their random motion because of the effects of an electric field (EF) motivates statistical approaches for investigating electrohydrodynamically (EHD) enhanced heat transfer. A theoretical model for boiling heat transfer under EHD is presented. The model is based on integral balance of momentum, energy, and interfacial area density, and consists of a system of three coupled equations: conservation of void fraction, bubble number density, and momentum of bubbles. Theoretical results are in qualitative agreement with the available experimental observations in the literature. © 2008 by Begell House, Inc  

    Enhancement of pool boiling heat transfer using ferromagnetic beads in a variable magnetic field

    , Article Applied Thermal Engineering ; Volume 164 , 2020 Rahmati, P ; Ebrahimi Dehshali, M ; Hakkaki Fard, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The pool boiling is one of the heat transfer mechanisms used in cooling systems. Using an external force to improve the efficiency of thermo-fluid systems is among the most effective approaches, and also highly applicable in enhancing heat transfer. In this study, the pool boiling of water, as the working fluid, in the presence of a variable magnetic field, is studied. To this end, ferromagnetic beads were placed on the boiling surface, and the effect of their movements due to a variable magnetic field was observed and measured. The number of beads was selected such that they would cover 1/3, 1/2 and 2/3 of the surface in different cases and the magnetic field was controlled by altering... 

    Modeling, Analysis and Possible Solution for Excessive Intraocular Pressure in Glaucoma Patients

    , M.Sc. Thesis Sharif University of Technology Singh, Dara (Author) ; Firouzbakhsh, Keykhosrow (Supervisor)
    Abstract
    With the advent of new computer technologies, computational analysis on the human organs has become tremendously popular in the field of medical science. Every year thousands of people suffer irreversible eye damages pertaining to lack of adequate medications. In this regards, enormous amount of money is spent annually but mostly in vain due to the irreversibility and silent nature of eye diseases like glaucoma. Yet more precise studies on the topic are requisite. In this thesis, a validated half 3D finite volume model of human eye considering the fluid flow in collaboration with heat transfer in the steady state utilizing the well known discretized bio-heat transfer equation coupled with... 

    An applicable method for efficiency estimation of operating tray distillation columns and its comparison with the methods utilized in HYSYS and Aspen Plus

    , Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 51, Issue 10 , October , 2015 , Pages 1393-1402 ; 09477411 (ISSN) Sadeghifar, H ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    Developing general methods that rely on column data for the efficiency estimation of operating (existing) distillation columns has been overlooked in the literature. Most of the available methods are based on empirical mass transfer and hydraulic relations correlated to laboratory data. Therefore, these methods may not be sufficiently accurate when applied to industrial columns. In this paper, an applicable and accurate method was developed for the efficiency estimation of distillation columns filled with trays. This method can calculate efficiency as well as mass and heat transfer coefficients without using any empirical mass transfer or hydraulic correlations and without the need to... 

    Experimental study of internal forced convection of ferrofluid flow in porous media

    , Article Defect and Diffusion Forum ; Vol. 348 , April , 2014 , pp. 139-146 ; ISSN: 10120386 ; ISBN: 9783038350002 Sehat, A ; Sadrhosseini, H ; Shafii, M. B ; Sharif University of Technology
    Abstract
    This work presents an experimental study of the effect of a magnetic field on laminar forced convection of a ferrofluid flowing in a tube filled with permeable material. The walls of the tube are subjected to a uniform heat flux and the permeable bed consists of uniform spheres of 3-mm diameter. The ferrofluid synthesis is based on reacting iron (II) and iron (III) in an aqueous ammonia solution to form magnetite, Fe3O4. The magnetite is mixed with aqueous tetra methyl ammonium hydroxide, (CH3) 4NOH, solution. The dependency of the pressure drop on the volume fraction, and comparison of the pressure drop and the temperature distribution of the tube wall is studied. Also comparison of the... 

    Application of homotopy and homotopy perturbation methods to differential equations of heat transfer and shear deformation of beams

    , Article Applied Mathematical Sciences ; Volume 5, Issue 21-24 , Apr , 2011 , Pages 1051-1063 ; 1312885X (ISSN) Manshadi, M. D ; Rohi, E ; Marzabadi, F. R ; Vaziry, M. A ; Sharif University of Technology
    2011
    Abstract
    In this paper, different physical differential equations related to heat transfer and shear deformation of beams are solved by new but powerful analytical methods: Liao's Homotopy method (H.M), Homotopy method with Pade approximation and the He's Homotopy-Perturbation Method (HPM). Nonlinear convective-radiative cooling equation, nonlinear heat equation with cubic nonlinearity and the shear deformation of sandwich beams are used as examples to illustrate the solution procedures. Comparison of the applied methods with exact solutions reveals that both methods are greatly effective  

    Experimental assessment of convective heat transfer coefficient enhancement of nanofluids prepared from high surface area nanoporous graphene

    , Article International Communications in Heat and Mass Transfer ; Volume 78 , 2016 , Pages 127-134 ; 07351933 (ISSN) Naghash, A. S ; Sattari, S ; Rashidi, A. M ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In this research convective heat transfer coefficient enhancement of nanofluids prepared from high surface area graphene has been investigated in laminar flow in the developing region. The nanofluid has been prepared from nanoporous graphene with high surface area and with concentration of 0.025 to 0.1 wt.%. Deionized water has been used as the base fluid and a type of Ter-Polymer has been utilized as the surfactant. The results indicate that thermal conductivity of nanofluid with concentration of 0.1 wt.% remains quite constant, with only 3.8% enhancement, while convective heat transfer coefficient improves significantly, with 34% enhancement. The behavior of this enhancement related to the... 

    Performance evaluation and optimization of encapsulated cascade PCM thermal storage

    , Article Journal of Energy Storage ; Volume 11 , 2017 , Pages 64-75 ; 2352152X (ISSN) Shamsi, H ; Boroushaki, M ; Geraei, H ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    One of the main components of any solar power plant is its thermal heat storage system. Heat storage reduces the cost of power generation by increasing the capacity factor of the system. This paper aims to model and optimize the operation of a consecutive multi-layer Phase Change Material (PCM) thermal heat storage system, named Cascade Latent Heat Storage (CLHS), using the method of characteristics and genetic algorithm. The model is validated through comparison with experimental data available in the literature. The model can predict fluid and PCM temperature, PCM phase and the energy absorbed by PCM. A sensitivity analysis is employed for both the PCM and the fluid parameters. The PCM... 

    Heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder: review and experiments

    , Article Applied Thermal Engineering ; Volume 120 , 2017 , Pages 257-268 ; 13594311 (ISSN) Nouri Borujerdi, A ; Nakhchi, M. E ; Sharif University of Technology
    Abstract
    This experimental work is an attempt to identify the most significant parameters influencing heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder. This type of flow known as Taylor-Couette flow has many industrial applications such as electrical power generators and rotating machineries. A comprehensive review of the previous works on flow regimes, heat transfer and pressure drop in grooved channels is provided. The experiments are conducted based on four different factors including Taylor number, 0

    Ballistic and collisional flow contributions to anti-fourier heat transfer in rarefied cavity flow

    , Article Scientific Reports ; Volume 8, Issue 1 , 2018 ; 20452322 (ISSN) Akhlaghi, H ; Roohi, E ; Stefanov, S ; Sharif University of Technology
    Abstract
    This paper investigates anti-Fourier heat transfer phenomenon in a rarefied gas confined within a lid-driven cavity using a novel flow decomposition technique in the direct simulation Monte Carlo (DSMC) method proposed by Stefanov and co-workers. An isothermal cavity with different degrees of flow rarefaction from near continuum to mid transition regimes was considered to investigate cold-to-hot heat transfer from ballistic/collision flow decomposition viewpoint. A new cold-to-hot heat transfer indicator in the form of a scalar product of normalized heat flow vector and normalized temperature gradient vector has been introduced for the overall, ballistic and collision parts of these vectors.... 

    Experimental study of internal forced convection of ferrofluid flow in non-magnetizable/magnetizable porous media

    , Article Experimental Thermal and Fluid Science ; Volume 96 , 2018 , Pages 441-450 ; 08941777 (ISSN) Shafii, M. B ; Keshavarz, M ; Sharif University of Technology
    Elsevier Inc  2018
    Abstract
    In this work, the 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 subjected to constant heat flux. A part of the tube contains a porous medium with paramagnetic properties and porosity of 0.46. Ferrofluid is composed of Fe3o4 and water with (CH3)4NOH as a surfactant that is prepared in three different volume fractions. The effects of constant and oscillating magnetic fields on convective heat transfer coefficient were examined for various Reynolds numbers, frequencies and volume fractions. The results show that the maximum enhancements of average heat transfer... 

    Effect of oxygen enrichment in spectral thermal radiation in an unconfined turbulent bluff-body flame

    , Article Proceedings of the International Symposium on Radiative Transfer, 3 June 2019 through 7 June 2019 ; Volume 2019-June , 2019 , Pages 83-91 ; 26425629 (ISSN); 9781567004793 (ISBN) Darbandi, M ; Barezban, M. B ; Fatin, A ; Bordbar, H ; Sharif University of Technology
    Begell House Inc  2019
    Abstract
    Oxy-fuel combustion is a modern technique to improve the efficiency and reduce environmental penalty of many combustion systems. In the present study, three different approaches of skipping radiation, weighted sum of gray gases (WSGGM), and spectral line based weighted sum of gray gases (SLW) have been used in simulation of an unconfined turbulent bluff-body flame. The model is first validated against existing experimental data and then used to study the effect of oxygen enhancement and different spectral radiation models. Due to small optical thickness of the studied system, predictions of all three different approaches are close. However, by increasing oxygen concentration in the oxidizer... 

    Assessment of SLW model in 3D non-gray gas radiation calculation

    , Article 6th International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2019, 18 June 2019 through 19 June 2019 ; 2019 ; 23693029 (ISSN); 9781927877593 (ISBN) Darbandi, M ; Barezban, M. B ; Schneider, G. E ; Sharif University of Technology
    Avestia Publishing  2019
    Abstract
    In this paper, the radiation heat transfer is calculated numerically in a three dimensional enclosure containing non-gray gases. The radiation heat transfer equation is solved using the finite-volume formulation of discrete ordinate method and the SLW model is employed to calculate the radiation absorption coefficients. Three cases are simulated here including the isothermal/homogeneous, isothermal/nonhomogeneous, and the non-isothermal/homogeneous media. The calculated radiation source terms and the wall heat fluxes are compared with the results of SNB method. It is shown that the SLW results are in very good agreement with the SNB in case of isothermal/homogeneous. In the two other cases,... 

    Assessment of SLW model in 3D non-gray gas radiation calculation

    , Article 6th International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2019, 18 June 2019 through 19 June 2019 ; 2019 ; 23693029 (ISSN); 9781927877593 (ISBN) Darbandi, M ; Barezban, M. B ; Schneider, G. E ; Sharif University of Technology
    Avestia Publishing  2019
    Abstract
    In this paper, the radiation heat transfer is calculated numerically in a three dimensional enclosure containing non-gray gases. The radiation heat transfer equation is solved using the finite-volume formulation of discrete ordinate method and the SLW model is employed to calculate the radiation absorption coefficients. Three cases are simulated here including the isothermal/homogeneous, isothermal/nonhomogeneous, and the non-isothermal/homogeneous media. The calculated radiation source terms and the wall heat fluxes are compared with the results of SNB method. It is shown that the SLW results are in very good agreement with the SNB in case of isothermal/homogeneous. In the two other cases,... 

    Experimental investigation in pool boiling heat transfer of pure/binary mixtures and heat transfer correlations

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 3 , September and October , 2008 , Pages 135-150 ; 10219986 (ISSN) Alavi Fazel, S. A ; Jamialahmadi, M ; Safekordi, A. A ; Sharif University of Technology
    2008
    Abstract
    Nucleate pool boiling heat transfer coefficient have been experimentally measured on a horizontal rod heater for various liquid binary mixtures. Measurements are based on more than three hundred data points on a wide range of concentrations and heat fluxes. In this investigation, it has been confirmed that the heat transfer coefficient in boiling solutions are regularly less than those in pure component liquids with same physical properties. Several reasons should be responsible for this phenomenon, but mainly it could be related to preferential evaporation of the more volatile component(s) during bubble formation. In this article, the performances of major existing correlations to the...