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    Effects of geometric factors and material properties on stress behavior in rotating disk

    , Article Indian Journal of Science and Technology ; Vol. 7, issue. 1 , Jan , 2014 , p. 1-6 Monfared, V ; Hassan, M ; Daneshmand, S ; Taheran, F ; Ghaffarivardavagh, R ; Sharif University of Technology
    Abstract
    In this study, effects of geometric factors and material properties are investigated on stress behavior of circular rotating disk with constant rotation in various industrial mechanisms using equilibrium equations, geometric relations and stress functions. In this way, research on a thin uniform and homogeneous circular disk under constant rotation is considered. The rotating motion produces centrifugal acceleration on each element of the rotating disk, and this rotating motion becomes the source of external loading for the mentioned problem. Additional exterior loadings are not assumed in this problem. It is comfortable to handle the centrifugal force loading by relating it to a body force... 

    Designing and modeling a centrifugal microfluidic device to separate target blood cells

    , Article Journal of Micromechanics and Microengineering ; Volume 26, Issue 3 , 2016 ; 09601317 (ISSN) Shamloo, A ; Selahi, Aa ; Madadelahi, M ; Sharif University of Technology
    Institute of Physics Publishing  2016
    Abstract
    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of... 

    Active control of surge in centrifugal compressors using a brain emotional learning-based intelligent controller

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 230, Issue 16 , 2016 , Pages 2828-2839 ; 09544062 (ISSN) Jokar, A ; Zomorodian, R ; Ghofrani, M. B ; Khodaparast, P ; Sharif University of Technology
    SAGE Publications Ltd  2016
    Abstract
    Efforts have been targeted at providing a comprehensive simulation of a centrifugal compressor undergoing surge. In the simulation process, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Two positive scenarios for the shaft speed, constant, and variable, were undertaken, and effects of load line on the dynamic response of the compressor have been studied. In order to achieve high-fidelity simulation in the variable speed case, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Moreover,... 

    Numerical simulation of centrifugal serpentine micromixers and analyzing mixing quality parameters

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 104 , 2016 , Pages 243-252 ; 02552701 (ISSN) Shamloo, A ; Madadelahi, M ; Akbari, A ; Sharif University of Technology
    Elsevier, B.V  2016
    Abstract
    Centrifugal microfluidics or the Lab on a CD (LOCD) has developed vast applications in biomedical researches and analyses. Fluid mixing is an application of the LOCD. In this paper, multiple centrifugal micromixers were simulated. Various parameters were originally presumed to have an effect on mixing performance. These parameters include inlet angle, angular velocity, cross-sectional profile, perpendicular length ratio and the number of channels in series. They were each analyzed through simulations. It was gathered that the inlet angle does not significantly affect the mixing quality. Increasing angular velocity steadily increases mixing quality for all geometries. The vertical triangular... 

    Experimental investigation of effects of the feed flow rate and “tail scoop-wall” clearance on the performance of a gas centrifuge by feeding a Freon mixture

    , Article Separation Science and Technology (Philadelphia) ; Volume 51, Issue 7 , 2016 , Pages 1259-1267 ; 01496395 (ISSN) Sadeghi, M. H ; Outokesh, M ; Karimi Sabet, J ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Abstract
    ABSTRACT: Experimental study of the performance of a gas centrifuge can be appreciably simplified if instead of isotopic mixtures, a binary mixture of gases with large molecular weight difference is used. The current study undertook this approach by injecting a 53%–47% (w/w) mixture of “Freon12-Freon22” into a gas centrifuge. The two parameters, whose investigation was the objective of the current study were: the feed flow rate (F), and the clearance between tail scoop and the rotor wall (d). The results demonstrated that changing the scoop-wall clearance has the most significant effect on the cut (θ), so that by fixing “d”, “θ” becomes nearly invariant. The head separation factor (α)... 

    A centrifugal microfluidic platform to measure hemoglobin of whole blood

    , Article 2017 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Mahmodi Arjmand, E ; Saadatmand, M ; Bakhtiari, M. R ; Eghbal, M ; Balaei, A ; Sharif University of Technology
    Abstract
    Microfluidics has been becoming more and more popular over last two decades. The reason for this, is inherent features of microfluidics including low consumption of samples and reagents, high sensitivity, short analysis time, and low cost. As well as, centrifugal microfluidics as a subset of microfluidics has been able to prove itself as a helpful tool in analytic assays. The main application of centrifugal microfluidic devices is being used in point-of-care testing systems. Herein, we presented a microfluidic disc for measuring hemoglobin(Hb) concentration in the EDTA-anticoagulated venous blood using cyanmethemoglobin method. In this experiment, at first a hand-made standard solution was... 

    Prediction of erosive wear locations in centrifugal compressor using CFD simulation and comparison with experimental model

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 41, Issue 2 , 2019 ; 16785878 (ISSN) Biglarian, M ; MomeniLarimi, M ; Ganji, B ; Ranjbar, A ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    Erosive wear is one of the efficiency reduction causes in centrifugal compressors. The presence of suspended solid particles in the fluid causes deformations in different parts of the compressor, especially blades of the impeller. Therefore, erosion not only decreases the part lifetime by destruction of blades form, but also increases energy losses. For this reason, specifying the erosion locations and choosing a suitable material have an important effect on optimum functionality of the machine. In this paper, erosion locations of a compressor impeller by using computational fluid dynamics (CFD) in high temperature and pressure are attained and compared with experimental model. The... 

    Analyzing mixing quality in a curved centrifugal micromixer through numerical simulation

    , Article Chemical Engineering and Processing: Process Intensification ; 2017 ; 02552701 (ISSN) Shamloo, A ; Vatankhah, P ; Akbari, A ; Sharif University of Technology
    Elsevier B.V 
    Abstract
    The Lab On a CD (LOCD), also known as Centrifugal Microfluidics, has evolved into a sophisticated platform for performing biomedical assays due to its marvelous miniaturization and accurate simulation of biological reactions. Among the numerous applications of the LOCD is fluid mixing. In this paper a centrifugal, serpentine micromixer is simulated and reformed toward better mixing performance. The micromixer was chosen to be curved as a curved design was found to be thrice as functional and compact as a rectilinear design, mixing-wise. The two angular velocity and opening radius parameters were originally hypothesized to affect mixing performance. Effect of angular velocity was studied over... 

    Analyzing mixing quality in a curved centrifugal micromixer through numerical simulation

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 116 , 2017 , Pages 9-16 ; 02552701 (ISSN) Shamloo, A ; Vatankhah, P ; Akbari, A ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    The Lab On a CD (LOCD), also known as Centrifugal Microfluidics, has evolved into a sophisticated platform for performing biomedical assays due to its marvelous miniaturization and accurate simulation of biological reactions. Among the numerous applications of the LOCD is fluid mixing. In this paper a centrifugal, serpentine micromixer is simulated and reformed toward better mixing performance. The micromixer was chosen to be curved as a curved design was found to be thrice as functional and compact as a rectilinear design, mixing-wise. The two angular velocity and opening radius parameters were originally hypothesized to affect mixing performance. Effect of angular velocity was studied over... 

    Investigation of Flow Rate and Cooling Water Temperature Effects on the Process Parameters in Centrifuge Machine

    , M.Sc. Thesis Sharif University of Technology Aghaei, Majid (Author) ; Otukesh, Mohammad (Supervisor) ; Safdari, Jaber (Supervisor)
    Abstract
    Centrifuge is a method in which great gravitational-like forces are used. Gravitational forces which cause molecules to move and are relevant to molecular weight; can cause isotope separation. The separation of light isotope from heavy one is done with a centrifugal field which produces a pressure gradient for the gas mixture. Pressure gradient is different for each of the isotopes due to the dependence of pressure gradient to the mass of the materials. But the separation in this way is very limited. The capacity of separation can be brought up by producing an additional axial flow in the rotor. This rotational flow can be produced with internal or external incitement. Rotational flow with... 

    A novel aerodynamic design method for centrifugal compressor impeller

    , Article Journal of Applied Fluid Mechanics ; Vol. 7, issue. 2 , July , 2014 , p. 329-344 Nili-Ahmadabadi, M ; Durali, M ; Hajilouy, A ; Sharif University of Technology
    Abstract
    This paper describes a new quasi-3D design method for centrifugal compressor impeller. The method links up a novel inverse design algorithm, called Ball-Spine Algorithm (BSA), and a quasi-3D analysis. Euler equation is solved on the impeller meridional plane. The unknown boundaries (hub and shroud) of numerical domain are iteratively modified by BSA until a target pressure distribution in flow passage is reached. To validate the quasi-3D analysis code, existing compressor impeller is investigated experimentally. Comparison between the quasi-3D analysis and the experimental results shows good agreement. Also, a full 3D Navier-Stokes code is used to analyze the existing and designed compressor... 

    Multilevel optimization of the splitter blade profile in the impeller of a centrifugal compressor

    , Article Scientia Iranica ; Volume 24, Issue 2 , 2017 , Pages 707-714 ; 10263098 (ISSN) Moussavi Torshizi, S. A ; Hajilouy Benisi, A ; Durali, M ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    In this research, multi-level optimization of the profile of the splitter blades of a turbocharger compressor is performed using genetic algorithm in order to improve its performance. Successive corrections of the profile at hub, mid-span, and shroud of the splitter blades, with the objective of decreasing the incidence losses at the leading edge and adjustment of the blade loading at the shroud, result in an impeller having improved splitter blades. The impeller flow field analysis shows that the optimization has been successful in reducing the flow leakage at the shroud region as well as the losses in the leading edge region. Although numerical simulations predict a decrease by 0.5% in... 

    Fluidic barriers in droplet-based centrifugal microfluidics: Generation of multiple emulsions and microspheres

    , Article Sensors and Actuators, B: Chemical ; Volume 311 , May , 2020 Madadelahi, M ; Madou, M. J ; Dorri Nokoorani, Y ; Shamloo, A ; Martinez Chapa, S. O ; Sharif University of Technology
    Elsevier B. V  2020
    Abstract
    Droplet generation is very important in biochemical processes such as cell encapsulation, digital PCR (Polymerase Chain Reaction), and drug delivery. In the present paper, a density-based method called “fluidic barrier” is introduced to produce multiple emulsions on a centrifugal microfluidic platform or Lab-on-a-CD (LOCD). We show that the density and the viscosity of the fluids involved are important parameters for predicting the characteristics of the droplets generated with this method. Moreover, we broadened this concept by using the fluidic barriers to separate reactive chemicals. As a proof of concept, alginate and CaCl2 solutions are separated by an oil barrier to control the... 

    Design and 1D Dynamic Modeling of an Axial-Centrifugal Compressor Matching

    , M.Sc. Thesis Sharif University of Technology Asghary, Maryam (Author) ; Ghorbanian, Kaveh (Supervisor)
    Abstract
    Overall performance improvement of gas turbine is available by modifying each component of cycle. The purpose of this research is to improve performance of a micro turbine with 200 KW power, by redesigning compressor set. Considerable increase in performance and stability occurs, by adding individual stage of axial compressor at the entry of centrifugal section. It should be noted that, this improvement occurs without a significant increase in size and without having to change the centrifugal compressor design.In this study, design of one stage axial compressor and three dimensional modeling is discussed after, modeling and preliminary design of centrifugal compressor. Then, after obtaining... 

    Comparing the Performance of Centrifuge, Membrane Filter and Filter Press for Clarification of Lipase Enzyme

    , M.Sc. Thesis Sharif University of Technology Taher Aslani, Ahmad Reza (Author) ; Rousta Azad, Reza (Supervisor)
    Abstract
    Lipases (Triacyl Glycerol Acyl Hydrolase, EC.3.1.1.3) are multidimensional biocatalysts which have many applications in food industrials, dairy, fats and oils processing, detergents, synthesis of pure chemical and pharmaceutical materials, paper industrial and cosmetics. Generally, industrial enzymes are produced extracellularly, so their separation from a low-cost complex medium (usually used for production) is one of the cost stages in their production process. Filtration is the most economical method of separation in the production of enzymes, but due to the small size of colloidal particles and cell masses present in the fermentation environment, its use is subject to limitations. In... 

    Study of Design and Manufacturing of Vane of Diffuser for Centrifugal Compressor

    , M.Sc. Thesis Sharif University of Technology Ravosh, Farshad (Author) ; Hajilouy Benisi, Ali (Supervisor)
    Abstract
    The purpose of this research is providing the preliminary study and designing, fabricating and installing diffuser vanes on the vaneless diffuser compressor to improve its overall performance. To meet the goal, the GT4082 turbocharger centrifugal compressor is chosen as the basis unit. The compressor is fully modeled, to predict the compressor performance curves. One dimensional and three dimensional models are provided, to simulate the compressor with vaneless diffuser as well as vaned diffuser. In one dimensional model, governing equations are continuity, energy, and state and also the empirical components losses coefficients of the compressor are used. In this method, fluid properties are... 

    Bending-torsional flutter of a cantilevered pipe conveying fluid with an inclined terminal nozzle

    , Article Journal of Sound and Vibration ; Volume 332, Issue 12 , 2013 , Pages 3002-3014 ; 0022460X (ISSN) Firouz Abadi, R. D ; Askarian, A. R ; Kheiri, M ; Sharif University of Technology
    2013
    Abstract
    Stability analysis of a horizontal cantilevered pipe conveying fluid with an inclined terminal nozzle is considered in this paper. The pipe is modelled as a cantilevered Euler-Bernoulli beam, and the flow-induced inertia, Coriolis and centrifugal forces along the pipe as well as the follower force induced by the jet-flow are taken into account. The governing equations of the coupled bending-torsional vibrations of the pipe are obtained using extended Hamilton's principle and are then discretized via the Galerkin method. The resulting eigenvalue problem is then solved, and several cases are examined to determine the effect of nozzle inclination angle, nozzle aspect ratio, mass ratio and... 

    Investigation on effect of centrifugal compressor volute cross-section shape on performance and flow field

    , Article Proceedings of the ASME Turbo Expo ; Volume 8, Issue PARTS A, B, AND C , 2012 , Pages 871-880 ; 9780791844748 (ISBN) Mojaddam, M ; Benisi, A. H ; Movahhedy, M. R ; Sharif University of Technology
    2012
    Abstract
    In this article, the effects of volute cross section shape and centroid profile of a centrifugal compressor volute were investigated. The performance characteristics of a turbocharger compressor were obtained experimentally by measuring rotor speed and flow parameters at the inlet and outlet of the centrifugal compressor. The three dimensional flow field model of the compressor was obtained numerically solving Navier- Stokes equations with SST turbulence model. The compressor characteristic curves were plotted. For model verification, the results were compared with experimental data, showing good agreement. Modification of a volute was performed by introducing a shape factor for volute cross... 

    Optimization of electrical power in multistage centrifugal compressors

    , Article 2011 IEEE International Conference on Control System, Computing and Engineering, ICCSCE 2011, Penang, 25 November 2011 through 27 November 2011 ; 2011 , Pages 193-197 ; 9781457716423 (ISBN) Mohammadi, H ; Kermani, M ; Sharif University of Technology
    Abstract
    Over the time, multistaging has proved to have some great benefits such as less electrical usage, so, nowadays; optimization of the electrical power usage in centrifugal compressors is an important issue to lead to the least usage of power. In this paper, we present a novel algorithm that provides this desire; it also shows different arrangement of the stages for the considered compressor. Simple single-stage compressor pressure ratio is normally limited by constraints of both aerodynamic and structural types. Reaching to minimum power leads to the least usage of electrical power. In this paper, we utilize theoretical relations which are extracted and have been presented a novel numerical... 

    Inertial particle focusing in serpentine channels on a centrifugal platform

    , Article Physics of Fluids ; Volume 30, Issue 1 , 2018 ; 10706631 (ISSN) Shamloo, A ; Mashhadian, A ; Sharif University of Technology
    American Institute of Physics Inc  2018
    Abstract
    Inertial particle focusing as a powerful passive method is widely used in diagnostic test devices. It is common to use a curved channel in this approach to achieve particle focusing through balancing of the secondary flow drag force and the inertial lift force. Here, we present a focusing device on a disk based on the interaction of secondary flow drag force, inertial lift force, and centrifugal forces to focus particles. By choosing a channel whose cross section has a low aspect ratio, the mixing effect of the secondary flow becomes negligible. To calculate inertial lift force, which is exerted on the particle from the fluid, the interaction between the fluid and particle is investigated...