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    Ferrofluidic open loop pulsating heat pipes: Efficient candidates for thermal management of electronics

    , Article Experimental Heat Transfer ; Vol. 27, issue. 3 , Dec , 2014 , p. 296-312 ; ISSN: 08916152 Mohammadi, M ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Hannani, S. K ; Sharif University of Technology
    Abstract
    Thermal management of electronic devices is presently a serious concern. This article investigates the thermal performance of a five-turn open-loop pulsating heat pipe in both start-up and steady thermal conditions. The effects of working fluid, namely water and ferrofluid, heat input, charging ratio, ferrofluid concentration, orientation, as well as application of magnetic field, are explored. Experimental results show that using ferrofluid enhances the thermal performance in comparison with the case of distilled water under certain conditions. In addition, applying a magnetic field on the open-loop pulsating heat pipe charged with ferrofluid improves its thermal performance. Charging... 

    Overall thermal performance of ferrofluidic open loop pulsating heat pipes: An experimental approach

    , Article International Journal of Thermal Sciences ; Volume 65 , 2013 , Pages 234-241 ; 12900729 (ISSN) Taslimifar, M ; Mohammadi, M ; Afshin, H ; Saidi, M. H ; Shafii, M. B ; Sharif University of Technology
    2013
    Abstract
    Pulsating heat pipes (PHPs) are simple, cheap, and efficient heat transfer devices. They have applications in electronic cooling. In the present research, an experimental investigation is conducted on startup and steady thermal performances of open loop pulsating heat pipes (OLPHPs). Effects of working fluid, heat input, non-condensable gases (NCGs), ferrofluid concentration, magnets location, and inclination angle on the thermal performance of OLPHPs have been considered. Obtained results show that using ferrofluid can improve the thermal performance in steady state condition. Furthermore, applying a magnetic field enhances the heat transfer characteristics of ferrofluidic OLPHPs in both... 

    Thermal performance of an open loop pulsating heat pipe with ferrofluid (Magnetic Nano-Fluid)

    , Article ASME 2012 3rd International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2012 ; 2012 , Pages 185-190 ; 9780791854778 (ISBN) Taslimifar, M ; Mohammadi, M ; Saidi, M. H ; Afshin, H ; Shafii, M. B ; Kazemzadeh Hannani, S ; Sharif University of Technology
    Abstract
    In the present research an experimental investigation is performed to explore the effects of working fluid, heat input, ferrofluid concentration, magnets location, and inclination angle on the thermal performance of an Open Loop Pulsating Heat Pipe (OLPHP). Obtained results show that using ferrofluid can improve the thermal performance and applying a magnetic field on the water based ferrofluid decreases the thermal resistance. It shows that at an inclination angle of the OLPHP to be zero, the thermal performance of the present OLPHP reduces. Best heat transfer capability was achieved at 67.5 degree relative to horizontal axis for all of working fluids. Variation of the magnets location... 

    Experimental investigation on thermal performance of closed loop pulsating heat pipes with soluble and insoluble binary working fluids and a proposed correlation

    , Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 55, Issue 2 , February , 2019 , pp 375–384 ; 09477411 (ISSN) Zamani, R ; Kalan, K ; Shafii, M. B ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    In this study, an experimental investigation was conducted from a thermal performance standpoint on closed-loop pulsating heat pipes (CLPHPs) with four different fluids and their water-based binary mixtures as working fluids with volume mixing ratios of 3:1, 1:1, and 1:3. Ethanol and acetone as two types of fluids that are soluble in water and, to unprecedentedly compare the behavior of insoluble mixtures with the soluble ones as the working fluids, toluene and hexane as two types that are insoluble in water were used. Additionally, to predict the thermal performance of the pure, soluble binary, and insoluble binary fluids simultaneously for the first time, a correlation was derived. © 2018... 

    Experimental investigation on thermal performance of closed loop pulsating heat pipes with soluble and insoluble binary working fluids and a proposed correlation

    , Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 55, Issue 2 , 2019 , Pages 375-384 ; 09477411 (ISSN) Zamani, R ; Kalan, K ; Shafii, M. B ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    In this study, an experimental investigation was conducted from a thermal performance standpoint on closed-loop pulsating heat pipes (CLPHPs) with four different fluids and their water-based binary mixtures as working fluids with volume mixing ratios of 3:1, 1:1, and 1:3. Ethanol and acetone as two types of fluids that are soluble in water and, to unprecedentedly compare the behavior of insoluble mixtures with the soluble ones as the working fluids, toluene and hexane as two types that are insoluble in water were used. Additionally, to predict the thermal performance of the pure, soluble binary, and insoluble binary fluids simultaneously for the first time, a correlation was derived. © 2018,... 

    Open-loop pulsating heat pipes charged with magnetic nanofluids: powerful candidates for future electronic coolers

    , Article Nanoscale and Microscale Thermophysical Engineering ; Volume 18, Issue 1 , 2014 , Pages 18-38 ; ISSN: 15567265 Mohammadi, M ; Taslimifar, M ; Haghayegh, S ; Hannani, S. K ; Shafii, M. B ; Saidi, M. H ; Afshin, H ; Sharif University of Technology
    Abstract
    The present research proposes an effective method to enhance the heat transport capability of conventional electronic coolers and improve their thermal management. Pulsating heat pipes (PHPs) are outstanding heat transfer devices in the field of electronic cooling. In the present study, two sets of open-loop pulsating heat pipes (OLPHPs) for two different magnetic nanofluids (with and without surfactant) were fabricated and their thermal performance was experimentally investigated. Effects of working fluid (water and two types of magnetic nanofluids), heating power, charging ratio, nanofluid concentration, inclination angle, application of a magnetic field, and magnet location are described.... 

    Experimental investigation of an open loop pulsating heat pipe using ferrofluid

    , Article ASME 2012 3rd International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2012 ; 2012 , Pages 175-184 ; 9780791854778 (ISBN) Mohammadi, M ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Saimak, K. H ; Sharif University of Technology
    Abstract
    The present work investigates the thermal performance of a five turn Open Loop Pulsating Heat Pipe (OLPHP). The effects of working fluid namely water and ferrofluid, heat input, ferrofluid concentration, charging ratio, and orientation will be considered. Experimental results show that using ferrofluids can enhance the thermal performance in comparison with the case of distilled water. In addition, applying a magnetic field on the OLPHP charged with ferrofluid reduces its thermal resistance. Variation of the ferrofluid concentration results in different thermal performance of the OLPHP. Best charging ratio for the distilled water and ferrofluid without magnetic field is 60 % in most of the... 

    Effects of surface coating of nanoparticles on thermal performance of Open Loop Pulsating Heat Pipes

    , Article ASME 2012 Heat Transfer Summer Conf. Collocated with the ASME 2012 Fluids Engineering Div. Summer Meeting and the ASME 2012 10th Int. Conf. on Nanochannels, Microchannels and Minichannels, HT 2012, 8 July 2012 through 12 July 2012 ; Volume 2 , 2012 , Pages 593-599 ; 9780791844786 (ISBN) Mehdi, T ; Maziar, M ; Ali, A ; Hossein, A ; Mohammad Hassan, S ; Mohammad Behshad, S ; Siamak, K. H ; Sharif University of Technology
    2012
    Abstract
    Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated.... 

    Thermal characteristics of closed loop pulsating heat pipe with nanofluids

    , Article Journal of Enhanced Heat Transfer ; Volume 18, Issue 3 , 2011 , Pages 221-237 ; 10655131 (ISSN) Jamshidi, H ; Arabnejad, S ; Shafii, M. B ; Saboohi, Y ; Sharif University of Technology
    2011
    Abstract
    In this paper, the effect of different parameters on the thermal operation of a Closed Loop Pulsating Heat Pipe (CLPHP) has been investigated. These parameters include the working fluid, the inclination angle, the filling ratio, and the input heat flux. The effect of nanoparticle mass concentrations has been analyzed as well. It was observed that the CLPHP can decrease thermal resistance up to 11.5 times compared to the same empty copper tube with thermal resistance of 9.4 K/W. Optimum thermal operation for a system with the water-silver nanofluid was achieved at conditions of the 50% filling ratio with thermal resistance of 0.9 K/W, and for the water-titanium oxide system, the optimal... 

    Experimental Investigation of Pulsating Heat Pipe Using Nano-Fluid

    , M.Sc. Thesis Sharif University of Technology Taslimifar, Mehdi (Author) ; Saidi, Mohammad Hassan (Supervisor) ; Afshin, Hossain (Supervisor) ; Shafiee, Mohammad Behshad (Supervisor)
    Abstract
    Considerable increase in speed and decrease in size of electronic devices results in increase of heat flux, so there is a need to enhance efficiency of cooling electronic devices. In the present research two sets of OLPHPs with five turns for two different magnetic nano-fluids were fabricated and the effects of working fluid (water, and two types of magnetic nano-fluids), working pressure, concentration, magnetic field, magnets location, and inclination angle on the thermal performance of OLPHPs have been considered in both startup and steady thermal conditions.
    Experimental results show that magnetic nano-fluids can improve thermal performance of the OLPHPs. Application of magnetic... 

    Experimental investigation on performance of a rotating closed loop pulsating heat pipe

    , Article International Communications in Heat and Mass Transfer ; Volume 45 , 2013 , Pages 137-145 ; 07351933 (ISSN) Aboutalebi, M ; Nikravan Moghaddam, A. M ; Mohammadi, N ; Shafii, M. B ; Sharif University of Technology
    2013
    Abstract
    Pulsating heat pipes (PHPs) are interesting heat transfer devices. Their simple, high maintaining, and cheap arrangement has made PHPs very efficient compared to conventional heat pipes. Rotating closed loop PHP (RCLPHP) is a novel kind of them, in which the thermodynamic principles of PHP are combined with rotation. In this paper, effect of rotational speed on thermal performance of a RCLPHP is investigated experimentally. The research was carried out by changing input power (from 25. W to 100. W, with 15. W steps) and filling ratio (25%, 50%, and 75%) for different rotational speeds (from 50. rpm to 800. rpm with an increment of 125. rpm). The results presented that at a fixed filling... 

    Experimental study of the startup performance of ferrofluidic open loop Pulsating Heat Pipes

    , Article ASME 2012 Heat Transfer Summer Conference Collocated with the ASME 2012 Fluids Engineering Div. Summer Meeting and the ASME 2012 10th Int. Conf. on Nanochannels, Microchannels and Minichannels, HT 2012, Rio Grande, 8 July 2012 through 12 July 2012 ; Volume 2 , 2012 , Pages 585-591 ; 9780791844786 (ISBN) Maziar, M ; Mehdi, T ; Siamak, K. H ; Mohammad Hassan, S ; Hossein, A ; Mohammad Behshad, S ; Sharif University of Technology
    2012
    Abstract
    Pulsating Heat Pipes (PHPs) are new and promising heat transfer devices. To implement the novel idea to vary the startup performance of a PHP using ferrofluid with and without the application of magnetic field, an experimental investigation is conducted. The effects of several important parameters including working fluid, charging ratio, heat input, ferrofluid concentration, internal pressure, and application of magnetic field on the startup performance of Open Loop Pulsating Heat Pipes (Open Loop PHPs) have been considered and described in detail. Obtained results show that using ferrofluid instead of distilled water can improve the startup performance of PHPs in certain conditions.... 

    Experimental study of evaporator surface area influence on a closed loop pulsating heat pipe performance

    , Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM, 8 July 2012 through 12 July 2012, Rio Grande ; Volume 2 , 2012 , Pages 233-238 ; 08888116 (ISSN) ; 9780791844762 (ISBN) Tabatabaee, M. H ; Mohammadi, M ; Shafii, M. B ; Sharif University of Technology
    Abstract
    Pulsating Heat Pipes are an effective mean for heat removal with the potential for a widespread application in electronic packaging. An experimental study a Closed Loop Pulsating Heat Pipe (CLPHP) constructed of copper tubes formed into four meandering turns is presented. Once configured in a vertical orientation the lower portion of the CLPHP comes in contact with a heat source (called the evaporator) from which it will remove heat through the pulsating action of the two-phase mixture contained within the initially evacuated copper tubes eventually transfer the heat to a heat sink (known as the condenser). Heat fluxes can be measured using temperature data gathered from experiments.... 

    Experimental investigation of the thermal management of flat-plate closed-loop pulsating heat pipes with interconnecting channels

    , Article Applied Thermal Engineering ; Volume 90 , 2015 , Pages 838-847 ; 13594311 (ISSN) Ebrahimi, M ; Shafii, M. B ; Bijarchi, M. A ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Abstract A desired circulatory flow in flat-plate closed-loop pulsating heat pipes (FP-CLPHPs), which may ameliorate electronic thermal management, was achieved by using the new idea of interconnecting channels (ICs) to decrease flow resistance in one direction and increase the total heat transfer of fluid. In order to experimentally investigate the effects of the IC, two aluminum flat-plate thermal spreaders - one with ICs (IC-FP-CLPHP) and one without them - were fabricated. The FP-CLPHPs were charged with ethanol as working fluid with filling ratios of 35%, 50%, 65%, and 80% by volume. Performance of interconnecting channels in different heat inputs was explored, and the results... 

    Experimental investigation of closed loop pulsating heat pipe with nanofluids

    , Article Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009 ; Volume 1 , 2009 , Pages 675-683 ; 9780791843567 (ISBN) Jamshidi, H ; Arabnejad, S ; Behshad Shafii, M ; Saboohi, Y ; Rasoulian, R ; Sharif University of Technology
    Abstract
    In this paper, the effect of several different parameters on the thermal resistance of a Closed Loop Pulsating Heat Pipe (CLPHP) has been investigated. These parameters include the working fluid, the inclination angle, the filling ratio and the heat influx. Also, the impact of using nanofluids with different nano-particle concentrations has been analyzed. It was observed that a CLPHP can increase the heat transfer up to 11.5 times compared to an empty pipe. Optimum performance for a system with the water-silver nanofluid was achieved at conditions of 50% filling ratio and 0.9 K/W of thermal resistance, and for the water-titanium oxide system, these optimal conditions were found to be 40%... 

    Thermal performance of rotating closed-loop pulsating heat pipes: experimental investigation and semi-empirical correlation

    , Article International Journal of Thermal Sciences ; Volume 123 , 2018 , Pages 14-26 ; 12900729 (ISSN) Ebrahimi Dehshali, M ; Alhuyi Nazari, M ; Behshad Shafii, M ; Sharif University of Technology
    Elsevier Masson SAS  2018
    Abstract
    A rotating closed loop pulsating heat pipe (RCLPHP) was experimentally investigated as a passive heat sink for rotary equipment cooling. The effects of heat input, rotational speed, filling ratio, and working fluid on the thermal resistance of RCLPHP were studied. Pure water and ethanol were used as working fluids with filling ratios of 30%, 50%, and 70% by volume, and the RCLPHP was tested at four rotational speeds: 200, 400, 600, and 800 rpm. The results showed that the best filling ratio for both water and ethanol is 50% and proved that the RCLPHP is able to work efficiently in a wide range of rotational speed. Moreover, it was observed that at the optimum filling ratio for ethanol and... 

    Numerical analysis of photovoltaic solar panel cooling by a flat plate closed-loop pulsating heat pipe

    , Article Solar Energy ; Volume 206 , 2020 , Pages 455-463 Alizadeh, H ; Alhuyi Nazari, M ; Ghasempour, R ; Shafii, M. B ; Akbarzadeh, A. A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Photovoltaic (PV) panels provide a suitable way for the direct conversion of solar energy into electricity. The electrical output and efficiency of PV modules are dependent on working temperature. The present study contributes to investigate the efficiency of utilizing a flat plate closed-loop pulsating heat pipe (CLPHP) to cool down a PV panel in both thermal and economic aspects. Accordingly, a numerical investigation is employed to obtain the surface temperature and electrical gain of the PV panel through four scenarios, including natural cooling without additional equipment, CLPHP-based passive cooling, CLPHP-based active cooling, and a conventional flat plate cooling methods. The...