Search for: pumping
Total 245 records
Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Safaei, H ; Sadjadi, B ; Pirouzpanah, S ; Sharif University of Technology
In this research a phase change micropump as a novel type of non-mechanical micropumps has been investigated. A one dimensional model has been developed to describe the pumping mechanism and assess the working characteristics of the micropump. Conservation of mass, momentum and energy have been employed to obtain an algebraic equation for the flow rate which depends on seven non-dimensional numbers. The governing equation has been solved to study the effect of various operating parameters on the micropump performance. To verify the analytical approach, an experimental set up has been constructed. The results show that the theoretical model is in reasonable agreement with the experimental...
Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 237-244 ; 09254005 (ISSN) ; Shafii, M. B ; Moosavi, A ; Amiri Hezave, H ; Sharif University of Technology
In this study, a novel prototype high-efficiency miniature pump that uses magnetic properties of a ferrofluid in both pumping and valving mechanisms is presented. The minichannel consisting of a cylindrical pumping chamber, a check valve, an inlet and an outlet, comprises six bonded layers of PMMA. A cylindrical permanent magnet that is placed inside the chamber and is externally actuated by a motorized off-center permanent magnet, functions as a revolving piston which sweeps the perimeter of the cylinder. Ferrofluid is used to cover the gaps between the magnetic piston and the channel walls, also serves as a separating plug between the inlet and the outlet of the chamber preventing...
Experimental study of a novel Magneto Mercury Reciprocating (MMR) micropump, fabrication and operation, Article Sensors and Actuators, A: Physical ; Volume 194 , 2013 , Pages 277-284 ; 09244247 (ISSN) ; Salari, A ; Shafii, M. B ; Sharif University of Technology
Today, MEMS have wide applications in modern technologies. Magneto hydro dynamic (MHD) micropumps play an important role in the MEMS industry and have been thoroughly studied in the recent years. In this study, the idea of classic reciprocating micropumps was combined with magneto hydro dynamics (MHD) to develop a novel Magneto Mercury Reciprocating (MMR) micropump. To attain this goal, the Lorentz force, as the actuation mechanism, was used to move a conductive liquid (mercury) slug in a reciprocating manner in order to suck the working fluid (air) from the inlet and pump it to the outlet. The performance of the fabricated MMR micropump was examined in terms of parameters such as pressure...
Technical assessment of ground-source, air-source, and hybrid heat pumps for single-family buildings in cold climates, Article 25 June 2016 through 29 June 2016 ; Volume 122 , 2016 , Pages 270-280 ; 00012505 (ISSN) ; 9781939200464 (ISBN) ; Hakkaki Fard, A. M ; Aidoun, Z ; Ouzzane, M ; Sharif University of Technology
Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc
This paper discusses a technical comparison of a directexpansion ground-source heat pump (DX-GSHP) and an airsource heat pump (ASHP). To lower the ground heat exchanger size for cost reduction purposes, the system performance of a hybrid system is also evaluated using a supplementary air evaporator combined with the DX-GSHP. Detailed screening models previously developed for ASHPs and DX-GHSPs are first used to compare the seasonal performance of these two options for a residential building in the cold-climate city of Montreal, Canada. Then, the model is adopted for performance evaluation of the hybrid system. Additionally, different parameters including borehole total length and heat pump...
Performance evaluation of a novel compact humidification-dehumidification desalination system coupled with a heat pump for design and off-design conditions, Article Energy Conversion and Management ; Volume 194 , 2019 , Pages 160-172 ; 01968904 (ISSN) ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd 2019
In this study, the theoretical investigation of a novel heat pump assisted humidification-dehumidification desalination system has been carried out. The conventional dehumidifier of the humidification-dehumidification system was removed and the evaporator of the heat pump was utilized for direct dehumidification of air. Besides, the heat pump condenser was used as the saline water heater of the humidification-dehumidification cycle. First, the sizes of the components were calculated at design conditions for fixed input operational conditions namely the ambient air temperature, relative humidity, and inlet saline water temperature. However, the input operating conditions vary at off-design...
Efflux pump inhibitory activity of biologically synthesized silver nanoparticles against multidrug-resistant Acinetobacter baumannii clinical isolates, Article Journal of Basic Microbiology ; Volume 60, Issue 6 , 2020 , Pages 494-507 ; Pargol, M ; Mirzaie, A ; Karizi, S. Z ; Noorbazargan, H ; Akbarzadeh, I ; Sharif University of Technology
Wiley-VCH Verlag 2020
This study was carried out to investigate the possible efflux pump inhibitory activity of biologically synthesized silver nanoparticles (AgNPs) against multidrug-resistant (MDR) Acinetobacter baumannii isolates. In this study, the physicochemical characteristics of synthesized AgNPs were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometer (FTIR) methods. Subsequently, MDR A. baumannii isolates were recovered from clinical samples and the phenotypic cartwheel efflux assay and polymerase chain reaction (PCR) were used to elucidate the possible presence of efflux pump in MDR...
Article Journal of Micro/ Nanolithography, MEMS, and MOEMS ; Volume 14, Issue 3 , July , 2015 ; 19325150 (ISSN) ; Salari, A ; Shafii, M. B ; Sharif University of Technology
A reciprocating single-chamber micropump is designed and experimentally tested. The actuation technique of the pump is based on Lorentz force acting on an array of low-weight microwires placed on a flexible membrane surface. A square-wave electric current (5.6 and 7.8 A) with a low-frequency range (5.6 to 7.6 Hz) is applied through the microwires in the presence of a perpendicular magnetic field (0.08 to 0.09 T). The resultant oscillating Lorentz force causes the membrane to oscillate with the same frequency, and pushes the fluid to flow toward the outlet using a high-efficiency ball-valve. The micropump has exhibited a maximum efficiency of 2.03% with a flow rate as high as 490 μl/s and...
Evaluation of a transient borehole heat exchanger model in dynamic simulation of a ground source heat pump system, Article Energy ; Volume 147 , March , 2018 , Pages 81-93 ; 03605442 (ISSN) ; Abbaspour, M ; Saidi, M. H ; Sharif University of Technology
Elsevier Ltd 2018
The performance of a vertical ground source heat pump system (GSHPS) largely depends on the fluid temperature leaving the borehole heat exchanger (BHE) that may be affected by the short-term behavior of the BHE. Although considerable research has been carried out to analyze the short-term transient response of the BHEs, few studies have investigated its impact on dynamic simulation of GSHPS. Therefore, this paper presents a numerical approach based on a transient BHE model to evaluate the performance of a residential GSHPS over short and long timescales. The numerical results are compared with the results of EnergyPlus software. It is shown that the proposed model can appropriately predict...
Article Journal of Petroleum Science and Engineering ; Volume 62, Issue 1 , 2014 , Pages 156-170 ; ISSN: 09204105 ; Raffiee, A. H ; Saidi, M. H ; Sharif University of Technology
Using gas-liquid lifting pumps is a quite different technology for pumping two or three phase flows rather than other types of pumping systems. Therefore, finding performance characteristic chart for this type of pumping system seems to be necessary. In this type of pumping system, the liquid phase is pushed upward by the compressed air which has been injected in the bottom of upriser pipe of the pump. Therefore, compressed air acts as the driving force in gas lifting pumps instead of moving parts in ordinary pumps. It can be concluded that the definition of characteristic curve used for ordinary pump is not very appropriate for this type of pumping system. In this study, it has been...
Article Energy ; Volume 80 , 2015 , Pages 496-508 ; 03605442 (ISSN) ; Jafari, M ; Kasiri, N ; Ivakpour, J ; Sharif University of Technology
Elsevier Ltd 2015
Finding efficient alternative to CDiC (Conventional Distillation Column) for methanol-water separation has been an attractive field of study in literature. In this work, five heat pump-assisted schemes are proposed and compared to each other to find the optimal one; (1) VRC (Vapor Recompression Column), (2) external HIDiC (Heat-Integrated Distillation Column), (3) intensified HIDiC with feed preheater, (4) double compressor intensified HIDiC-1, and (5) double compressor intensified HIDiC-2. GA (Genetic Algorithm) is then implemented for optimization of the schemes when TAC (Total Annual Cost) is its objective function. During optimization, two new variables are added for using only...
Experimental investigation of heat recovery in a humidification-dehumidification desalination system via a heat pump, Article Desalination ; Volume 437 , 2018 , Pages 81-88 ; 00119164 (ISSN) ; Jafargholi, H ; Faegh, M ; Sharif University of Technology
Elsevier B.V 2018
A hybrid HDH desalination system integrated with a heat pump was experimentally studied. In this system, heat pump's heating was used to raise the temperature of the air entering the humidifier and its cooling effect was used for dehumidification of humid air and freshwater production. In other words, heat pump's condenser works as the heater of the HDH cycle and its evaporator works as the coolant for the dehumidifier of HDH cycle. The effects of different parameters such as mass flow rate of inlet saline water (relative humidity of the air passing the dehumidification section), volume flow rate of the air passing the dehumidification section and ambient air temperature on freshwater...
Economic and environmental assessment of a solar-assisted ground source heat pump system in a heating-dominated climate, Article International Journal of Environmental Science and Technology ; 2018 , Pages 1-8 ; 17351472 (ISSN) ; Saidi, M. H ; Abbaspour, M ; Sharif University of Technology
Center for Environmental and Energy Research and Studies 2018
In recent years, increasing attention has been paid to the use of renewable energy sources in building sector. The ground source heat pumps are a promising alternative for heating and cooling applications. Despite the high coefficients of performance and significant environmental benefits, their performance may deteriorate over the long-term operation if the annual ground loads are not well balanced. An appropriate solution is the use of hybrid ground source heat pump system through which some portion of the thermal loads can be offset by supplemental components. The aim of this study is to assess the feasibility of a solar-assisted ground source heat pump system for heating a detached house...
Long-term energy and exergy analysis of heat pumps with different types of ground and air heat exchangers, Article International Journal of Refrigeration ; Volume 100 , 2019 , Pages 414-433 ; 01407007 (ISSN) ; Hakkaki Fard, A ; Sharif University of Technology
Elsevier Ltd 2019
Heat pumps as the only end-use cooling/heating technology with a Coefficient of Performance (COP) greater than one, have attracted a great deal of attention over the past decade. In this study, the long-term energy and exergy analysis of four different types of heat pump systems: a common Air Source Heat Pump (ASHP), an ASHP with Ground Air Heat Exchanger (GAHE), a Ground Source Heat Pump (GSHP) with Horizontal Ground Water Heat Exchanger (HGWHE), and a GSHP with Vertical Ground Water Heat Exchanger (VGWHE) is performed. It is considered that all systems are used for space cooling and heating of a residential building. A mathematical model that takes into account the variations of building...
M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi ; Firouzbakhsh, Keikhosrow
The heart is a powerful muscle whose primary function is to pump blood into the body. many cardiac patients reach a stage that can no longer be kept function of their heart to a satisfactory level by using medication thus doctors undergo surgery. The common problem occurs to most patients undergoing cardiac surgery is that after the surgery, the patient's heart during a short period of time is unable to supply blood with the flow rate and pressure required for all organs, especially the end organs of the body. In this conditions, ventricular assist device help the patients. These devices are used parallel with patient’s heart and supply the large portion of blood that patient’s body needs....
Article Journal of Luminescence ; Volume 131, Issue 11 , 2011 , Pages 2395-2399 ; 00222313 (ISSN) ; Asadpour, S. H ; Sadighi Bonabi, R ; Sharif University of Technology
We theoretically investigate the optical bistability (OB) in a V-type three-level atomic system confined in a unidirectional ring cavity via incoherent pumping field. It is shown that the threshold of optical bistability can be controlled by the rate of an incoherent pumping field and by interference mechanism arising from the spontaneous emission and incoherent pumping field. We demonstrate that the optical bistability converts to optical multi-stability (OM) by the quantum interference mechanism
Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7 February 2015 through 9 February 2015 ; Volume 9320 , 2015 ; 16057422 (ISSN) ; 9781628414103 (ISBN) ; Hakimsima, A ; Shafii, M. B ; Sharif University of Technology
Lorentz force is the pumping basis of many electromagnetic micropumps used in lab-on-a-chip. In this paper a novel reciprocating single-chamber micropump is proposed, in which the actuation technique is based on Lorentz force acting on an array of microwires attached on a membrane surface. An alternating current is applied through the microwires in the presence of a magnetic field. The resultant force causes the membrane to oscillate and pushes the fluid to flow through microchannel using a ball-valve. The pump chamber (3 mm depth) was fabricated on a Polymethylmethacrylate (PMMA) substrate using laser engraving technique. The chamber was covered by a 60 μm thick hyper-elastic latex rubber...
Article Laser Physics ; Volume 27, Issue 8 , 2017 ; 1054660X (ISSN) ; Souri, S ; Gohari Kamel, N ; Sadighi Bonabi, R ; Sharif University of Technology
Institute of Physics Publishing 2017
The lasing mechanism and temporal output profile of distributed feedback dye lasers is investigated, using a model based on induced polarization in the dye solution, where a more accurate behavior of the laser output is predicted. It is found that the temporal output profile of the laser is mostly determined by the concentration of dye solution and the lifetime of the upper laser level of dye molecules. To a large extent, the results of this work agree with experimental studies, even at high-level pump intensities where the self Q-switched model fails to be applied. Especially, the experimentally observed irregular intensity profile of laser output is explained. It is also shown that, when...
Article Laser Physics ; Volume 27, Issue 4 , 2017 ; 1054660X (ISSN) ; Rahbari, M ; Sadighi Bonabi, R ; Sharif University of Technology
Institute of Physics Publishing 2017
The generation of a single and stable picosecond pulse by distributed feedback dye laser is investigated in this work. The numerical result for the rate equation system that includes the thermal effects in the lasing medium is provided. By applying this model to Rhodamine 6G, it is found that considerable improvement in the stability of the laser can be achieved by pumping the system with narrower laser pulses. The simulation shows that if the dye solution is pumped by sub-200 ps pulse, the laser can be operated in single-pulse output mode with acceptable stability in pulsewidth over a long range of pumping intensity. This result is confirmed by a more complicated model composed of...
The dynamics of gain-coupled distributed feedback dye laser: Feedback mechanism and laser field evolution, Article Laser Physics ; Volume 28, Issue 9 , 2018 ; 1054660X (ISSN) ; Alijabbari, M ; Gohari Kamel, N ; Golshani, M ; Sadighi Bonabi, R ; Sharif University of Technology
Institute of Physics Publishing 2018
The temporal and spatial evolution of the two counter-propagating laser waves inside the active medium of a gain coupled distributed feedback dye laser is studied via a dynamic model. More specifically, the feedback mechanism, the temporal and spatial evolution of laser waves, the interaction between them, and the effect of pump pulse characteristics on the feedback strength are explained. It is shown that a pumping configuration with a spatial Gaussian pattern strongly decreases the laser pulse energy. This has never proposed or described by other models in the literature. For a narrow Gaussian pump pulse, the distributed feedback lasing on both sides of the active medium vanishes and...
Performance improvement of mixed-flow centrifugal pumps with new impeller shrouds: Numerical and experimental investigations, Article Renewable Energy ; Volume 163 , 2021 , Pages 635-648 ; 09601481 (ISSN) ; Khalesi, J ; Jafari, M ; Gazori, H. O ; Sharif University of Technology
Elsevier Ltd 2021
A new impeller configuration with innovatively-designed shrouds is introduced, and its impact on the pressure head and efficiency of the semi-open centrifugal pump is explored using experimental and numerical approaches. The proposed design includes attaching specific plates called bladelets to a semi-open impeller to limit the secondary flows over the blades resulting in an increase in the pump head and efficiency. Hydraulic performance of a centrifugal pump with three different bladelets at angles of 30°, 60°, and 90° is investigated experimentally, and the results are compared to semi-open and closed impellers. The values of pressure head and efficiency of the proposed centrifugal pump...