Search for: heat-transfer-mechanism
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    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
    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  

    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
    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... 

    Performance analysis of contact baking of flat bread in an indirect-heating oven

    , Article Drying Technology ; Volume 30, Issue 9 , May , 2012 , Pages 1014-1023 ; 07373937 (ISSN) Karimi, G ; Feilizadeh, M ; Najafabadi, A. T ; Sharif University of Technology
    A significant portion of Iranian flat breads are produced in semi-industrial, indirect-heating ovens. Therefore, an efficient oven design and a proper selection of operating conditions are crucial to improve the product quality and reduce energy consumption. In the present study, a mathematical model is developed to simulate a semi-industrial, indirect-heating, continuous oven performance during contact baking of an Iranian flat bread, referred to as Taftoon. Individual modes of heat transfer are considered among various components of the baking system to estimate the system performance and the bread quality in terms of design and operating conditions. The predictions of this model are in... 

    Innovative semi-analytical methodology to predict automobile body temperature distribution in the curing ovens

    , Article Heat Transfer Engineering ; Volume 33, Issue 2 , Jun , 2012 , Pages 109-117 ; 01457632 (ISSN) Hanafizadeh, P ; Sajadi, B ; Saidi, M. H ; Sharif University of Technology
    In automobile painting industries, new automobile body products frequently should be tested in order to determine the actual thermal behavior of a paint curing process before starting mass production. During the hardening processes of dipped paint coating, applied in the electrophoretic enameling process, or top paint coating, applied in the final coating process, the automobile body must be warmed up according to the specific paint manufacturer curve. Consequently, prediction of car body temperature during the curing process may be vital in the design and performance analysis of the paint ovens. Numerical simulation of these processes may reduce expensive and time-consuming experimental... 

    Advanced heat transfer analysis of a U-shaped pulsating heat pipe considering evaporative liquid film trailing from its liquid slug

    , Article Applied Thermal Engineering ; Volume 138 , 28 June , 2018 , Pages 475-489 ; 13594311 (ISSN) Nemati, R ; Behshad Shafii, M ; Sharif University of Technology
    Elsevier Ltd  2018
    In order to study the heat transfer mechanism and predict the heat transfer capability of a pulsating heat pipe (PHP), a numerical model was used to simulate the oscillating behavior of liquid slug considering liquid film thickness in the evaporator and reduction of liquid film thickness due to evaporation. In this article, thermal performance of an open loop closed end PHP of copper with a diameter of 1 mm and various working fluids including water (DW) and ethanol was investigated. The governing equations of mass, momentum, and energy equations were solved for liquid slug and vapor plugs. The results showed that by considering liquid film thickness behind the liquid slug, for both the...