Search for: filling-ratio
Design and performance of a novel hybrid photovoltaic–thermal collector with pulsating heat pipe (PVTPHP), Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 43 , 2019 , Pages 371-381 ; 22286187 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Springer International Publishing 2019
Hybrid photovoltaic–thermal collectors (PVT) are cogeneration components that convert solar energy into both electricity and heat. Pulsating heat pipe (PHP) is a fast-responding, flexible and high-performance thermal-conducting device. The aim of this work is design and performance of a novel hybrid photovoltaic–thermal collector with pulsating heat pipe (PVTPHP) for improving the electrical efficiency, by reducing the photovoltaic panel’s temperature, as well as taking advantage of the thermal energy produced. An experimental setup of PVTPHP is constructed, and its operating parameters are measured. The measured parameters include solar radiation intensity, ambient temperature, filling...
M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad
Developing of electric instruments with high performance needs high capacity heat transfer equipments. Pulsating heat pipes have better performance compared with normal heat pipes and can be used for cooling electronic instruments in near future. Also, one specific kind of heat pipes, which is called rotating pulsating heat pipe, can be used in cooling the turbine blades. Rotating pulsating heat pipe is a mechanism in which the pipes can rotate around the axis perpendicular to the plane of pipes. In this research one rotating heat pipe was built and the effects of heat input, filling ratio and rotational acceleration were examined experimentally. The Innovation in the research was to obtain...
M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad
Developing of electric instruments with high performance needs high capacity heat transfer equipments. Pulsating heat pipes have better performance compared with normal heat pipes and can be used for cooling electronic instruments in near future. Also, one specific kind of heat pipes, which is called rotating pulsating heat pipe, can be used in cooling the turbine blades and every rotating device. Rotating pulsating heat pipe is a cooling device in which the pipes can rotate around the axis perpendicular to the plane of pipes. In this research one rotating heat pipe was built and the effects of heat input, filling ratio, working fluid and rotational acceleration were examined experimentally,...
M.Sc. Thesis Sharif University of Technology ; Behshad Shafiei, Mohammad
technologies for cooling of electronic devices, have high efficiency due to the heat transfer in two-phase state. In this project, experimental effects of asymmetric triangle groove has been studied on the boiling fluid and effect of the motion on the boiling and heat pipe. Therefore, the experiment has been done by 3 heat pipes and each with 3 plates. The plates consist of a smooth plate, a plate with triangle groove and a plate with rectangle groove. Each heat pipe was filled by methanol in volumetric percentage from 10 to 60. The results show that 20 percent methanol is the optimum for all kind of heat pipe, which has been used. In addition, it is shown that heat pipe with triangle groove...
Experimental investigation of the effect of using closed-loop pulsating heat pipe on the performance of a flat plate solar collector, Article Journal of Renewable and Sustainable Energy ; Volume 5, Issue 1 , 2013 ; 19417012 (ISSN) ; Mamouri, S. J ; Shafii, M. B ; Rahni, M. T ; Sharif University of Technology
In this study, performance of a flat plate solar collector operating in conjunction with a closed-loop pulsating heat pipe is investigated experimentally. The experiments were carried out in Yazd, Iran. The experimental setup consisted of a flat plate solar collector, pulsating heat pipe, and a tank. The pulsating heat pipe's evaporator is located inside the flat plate collector. In order to investigate the effect of the evaporator length on the efficiency of the system, three different length collectors are manufactured in the evaporating section. In addition, the effects of the pulsating heat pipe filling ratio, inclination angle, and flow rate are investigated for each collector...
M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan ; Kazemzadeh Hannani, Siamak ; Shafii, Behshad
Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer. PHPs are widely used in solar water heaters, solar desalination systems, etc. In this research, thermal performance of Open Loop Pulsating Heat Pipes (OLPHPs) using three different ferrofluids (ferrofluid without surfactant and nanoparticles’ coating, ferrofluid with coating of nanoparticles, and ferrofluid with surfactant) is experimentally investigated. In addition, effects of charging ratio (20, 40, 60, and 80%), heating power (20, 30, 40, 50, 60, 70, 80, 100, 120, 140, 160, 180, 200, 240, 280, 320,...
Visualization of Flow Pattern and Experimental investigation of Thermal Performance in a FerroFluid Charged Pulsating Heat Pipe, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad
Nowadays, there is rapid development of practical engineeringsolutions to a multitude ofheating problems. Heat generated inmicro-devices used in manufacturing and electronics require specialsolutions. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer and previous researches show that using ferrofluid (magnetic nanofluid) in Pulsating Heat Pipes (PHPs) enhances the thermal performance in comparison with the case of distilled water under certain conditions by applying magnetic fields and the performance is dramatically improved at horizontal heating mode. In this research an experimental setup for visualizing two phase flows in a flat-plate Pulsating...
Visualization and Investigation of The Influence of the Connecting Channels on Flat-Plate Pulsating Heat-Pipes’ Heat-Transfer, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad
A desired circulatory flow in flat-plate pulsating heat-pipes may improve electronic thermal management. This desired flow can be achieved by fabricating connecting channels (CCs) to increase flow resistance in one direction. In addition, connecting channels may increase the freedom degree of fluid. In order to investigate the effect of CC, two aluminum flat plate thermal spreaders with overall size 320mm×220mm×5mm - one with CC (CC-FPHP) and one without it- were fabricated. Both of the speaders have square channels with crosssection 2mm×2.8mm. The FPHPs were charged with ethanol as working fluid with filling ratios of 35%, 50%, 65%, and 80% by volume. Performance of connecting-channels in...
Article International Communications in Heat and Mass Transfer ; Volume 45 , 2013 , Pages 137-145 ; 07351933 (ISSN) ; Nikravan Moghaddam, A. M ; Mohammadi, N ; Shafii, M. B ; Sharif University of Technology
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...
Article Desalination ; Volume 311 , 2013 , Pages 206-210 ; 00119164 (ISSN) ; Ghiasi, M ; Jahangiri Mamouri, S ; Shafii, M. B ; Sharif University of Technology
The application of the solar energy in thermal desalination devices is one of the most beneficial applications of the renewable energies. In this study, a novel solar desalination system is introduced, which is benefited from the undeniable advantages of pulsating heat pipe (PHP) as a fast responding, flexible and high performance thermal conducting device. Results show a remarkable increase in the rate of desalinated water production and the maximum production reaches up to 875mL/(m2.h). However, the optimum water depth in basin and the filling ratio of the PHP are measured 1cm and 40%, respectively
Experimental and numerical investigation of the thermal performance of a novel sintered-wick heat pipe, Article Applied Thermal Engineering ; Volume 94 , 2016 , Pages 59-75 ; 13594311 (ISSN) ; Shafii, M. B ; Sharif University of Technology
Thermal performance of a novel sintered wick heat pipe was investigated in this study. Two types of sintered wick heat pipes were fabricated and tested at different filling ratios of water, and their thermal resistances in different modes were compared. In the first type, wick was sintered annularly (conventional type), and in the other one (novel type of sintered wick) it was sintered only in one third of cross-section. Results showed that dry-out occurs at higher heat input by an increase in the filling ratio. Moreover, the best filling ratio is 20% for both heat pipes. Thermal resistances of the partly sintered wick heat pipe are approximately 28%, 17% and 47% lower than those of the...
Investigating thermal performance of a partly sintered-wick heat pipe filled with different working fluids, Article Scientia Iranica ; Volume 23, Issue 6 , 2016 , Pages 2616-2625 ; 10263098 (ISSN) ; Shaii, M. B ; Sharif University of Technology
Sharif University of Technology 2016
Heat pipes are important cooling devices that are widely used to transfer high heat loads with low temperature differences. In this paper, thermal performance of a novel type of sintered-wick heat pipe, namely, partly sintered-wick heat pipe, was investigated. The heat pipe was filled with degassed water and acetone, as working uids, and effects of filling ratio, orientation, and heat inputs were tested. Moreover, conditions at which dryout occurred were presented. The results showed that the best filling ratio for both working uids is about 20%. The heat pipe filled with water has better thermal performance than that filled with acetone; thus, the thermal resistances of the 20% water-filled...
Article Applied Thermal Engineering ; Volume 116 , 2017 , Pages 56-65 ; 13594311 (ISSN) ; Saidi, M. H ; Shafii, M. B ; Vandadi, M ; Kalan, K ; Sharif University of Technology
Elsevier Ltd 2017
Pulsating heat pipes (PHPs) are among the best solutions for the electronics cooling due to their low cost, effectiveness and being passive. Experiments to study the effective factors on heat transfer performance have been designed and as a result, improvement of ferrofluid PHP performance has been achieved. Two different heat pipes made of copper and glass were prepared to investigate the behavior of magnetic nanofluids. In order to find the best condition for heat transfer performance, different concentrations of nanofluid with a filling ratio of 50% were tested in 3 different cases of magnetic field. The results indicated that the ferrofluid is more stable in the glass PHP. It also shows...
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) ; Mohammadi, M ; Shafii, M. B ; Sharif University of Technology
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....
Article Experimental Thermal and Fluid Science ; Volume 42 , 2012 , Pages 6-15 ; 08941777 (ISSN) ; Soltanieh, M ; Shafii, M. B ; Sharif University of Technology
In this study, the aim is to investigate the application of pulsating heat pipes (PHPs) as a heat transfer tool in a solar water heater (SWH). For this purpose, an extra-long pulsating heat pipe (ELPHP) is designed, constructed and installed in a thermosyphon solar water heater. In this work the ELPHPs are made of copper tubes of internal diameter 2.0. mm. The number of meandering turns is 6 and the working fluid employed is distilled water. The lengths of condenser and evaporator sections are 0.8 and 0.96. m, respectively. The length of adiabatic section varies between 0.7 and 1.8. m. Inclination of the ELPHPs varies between 15° and 90° but is 45° for evaporator section. Four different...
Article Journal of Enhanced Heat Transfer ; Volume 18, Issue 3 , 2011 , Pages 221-237 ; 10655131 (ISSN) ; Arabnejad, S ; Shafii, M. B ; Saboohi, Y ; Sharif University of Technology
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...
Article Heat Transfer Engineering ; Volume 31, Issue 10 , Oct , 2010 , Pages 854-861 ; 01457632 (ISSN) ; Arabnejad, S ; Saboohi, Y ; Jamshidi, H ; Sharif University of Technology
Pulsating heat pipes are complex heat transfer devices, and their optimum thermal performance is largely dependent on different parameters. In this paper, in order to investigate these parameters, first a closed-loop pulsating heat pipe (CLPHP) was designed and manufactured. The CLPHP was made of copper tubes with internal diameters of 1.8 mm. The lengths of the evaporator, adiabatic, and condenser sections were 60, 150, and 60 mm, respectively. Afterward, the effect of various parameters, including the working fluid (water and ethanol), the volumetric filling ratio (30%, 40%, 50%, 70%, 80%), and the input heat power (5 to 70 W), on the thermal performance of the CLPHP was investigated...
Article Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009 ; Volume 1 , 2009 , Pages 675-683 ; 9780791843567 (ISBN) ; Arabnejad, S ; Behshad Shafii, M ; Saboohi, Y ; Rasoulian, R ; Sharif University of Technology
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%...
Enhancement of biological nitrogen removal performance using novel carriers based on the recycling of waste materials, Article Water Research ; Volume 170 , March , 2020 ; Borghei, S. M ; Raie, M ; Sharif University of Technology
Elsevier Ltd 2020
This study aims to enhance biological nitrogen removal performance by the innovative carbon-based carriers. The new carriers were produced based on recycling waste materials. In these carriers, the advantages of the hybrid system and physicochemical properties of activated carbon were integrated to promote microbial attachment. To verify the performance of the new carriers compared to the conventional moving carriers, the experiments were conducted in two parallel laboratory-scale sequencing batch reactors under various operating conditions. The analysis revealed that the specific surface area of the new carrier with a total pore volume of 0.0015cm3/gr was 10.9 times the specific surface...