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Effect of active feather length on aerodynamic performance of airfoils at low reynolds number flow
, Article AIAA AVIATION 2020 FORUM, 15 June 2020 through 19 June 2020 ; Volume 1 PartF , 2020 ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2020
Abstract
To increase the flight endurance of a Micro air vehicle (MAVs), which operates at low Reynolds number flow, one way is to harvest energy during its flight. By inspiring from the nature when all the birds use their feathers to control and distribute their power along the flying time, a solution might be design of a piezoelectric plate as feathers, which scavenges energy directly from the fluid flow. Cantilevered beam with piezo-ceramic layer undergoing vortex-induced vibrations can convert the mechanical energy available from the ambient environment to a usable electrical power. Since a flow-driven piezoelectric composite beam takes a form of natural three-way coupling of the turbulent fluid...
Developing an improved 1-D thermoflow approach to analyze turbine vane temperature distribution
, Article AIAA Scitech Forum, 6 January 2020 through 10 January 2020 ; Volume 1 Part F , 6-10 January , 2020 ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2020
Abstract
This study presents an improved one-dimensional approach, which is coupled with the 3D numerical flow solver, to find the temperature distribution over a typical turbine vane. The developed code solves the one-dimensional flow and heat transfer distribution in cooling flow passages inside a turbine vane. It uses our previous developed version and uses experimental correlations to predict the heat transfer coefficient and friction factor for each cooling passage. On the other hand, the hot gas flow field and conduction inside the vane material are solved using a 3D numerical solver. Our survey shows that cooling channel’s wall temperature has effect on the convective heat transfer coefficient...
Numerical study to optimize the melting process of phase change material coupled with extra fluid
, Article AIAA Scitech Forum, 2020, 6 January 2020 through 10 January 2020 ; Volume 1 PartF , 2020 ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2020
Abstract
Several methods have been proposed and explored to improve the performance of the energy storage unit. This work numerically investigates the melting process of a phase change material in a rectangular enclosure in presence of an auxiliary fluid considering different volume ratios. This investigation aims to obtain the volume ratio at which the amount of energy storage in the system becomes optimized for a specified time period. Oleic acid with a melting point of 13.5 °C is selected as the phase change material and water as a fluid with a higher density than oleic acid is chosen as the auxiliary fluid. Imposing the auxiliary fluid on top of the oleic acid, a displacement occurs between the...
DSMC solution of supersonic scale to choked subsonic flow in micro to nano channels
, Article 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, Darmstadt, 23 June 2008 through 25 June 2008 ; Issue PART A , 2008 , Pages 985-993 ; 0791848345 (ISBN); 9780791848340 (ISBN) ; Darbandi, M ; Mirjalili, V ; ASME ; Sharif University of Technology
2008
Abstract
In this study, the supersonic and choked subsonic flows through micro/nano channels are investigated using direct simulation Monte Carlo (DSMC) method. The supersonic case is simulated at different Knudsen numbers covering slip to transition flow regimes, while the effects of inlet Mach and back pressure are studied in details. The inlet/outlet pressure boundary conditions are suitably implemented benefiting from the basics of characteristics theory. A behavior similar to the one predicted by the Fanno theory is observed here; i.e., the supersonic flow velocity decelerates up to a choking condition where any further increase in Knudsen number is impossible unless strong normal/oblique shocks...
Three-dimensional compressible-incompressible turbulent flow simulation using a pressure-based algorithm
, Article Computers and Fluids ; Volume 37, Issue 6 , 2008 , Pages 747-766 ; 00457930 (ISSN) ; Darbandi, M ; Taeibi Rahni, M ; Sharif University of Technology
2008
Abstract
In this work, we extend a finite-volume pressure-based incompressible algorithm to solve three-dimensional compressible and incompressible turbulent flow regimes. To achieve a hybrid algorithm capable of solving either compressible or incompressible flows, the mass flux components instead of the primitive velocity components are chosen as the primary dependent variables in a SIMPLE-based algorithm. This choice warrants to reduce the nonlinearities arose in treating the system of conservative equations. The use of a new Favre-averaging like technique plays a key role to render this benefit. The developed formulations indicate that there is less demand to interpolate the fluxes at the cell...
Evaluation of rans approach in predicting the physics of incompressible turbulent jets-into-crossflow
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 8 PART A , 2008 , Pages 683-698 ; 0791843025 (ISBN); 9780791843024 (ISBN) ; Taeibi Rahni, M ; Darbandi, M ; Sharif University of Technology
2008
Abstract
This work is conducted with evaluation of different turbulence models capabilities in predicting three dimensional jet-into-crossflow (JICF) interactions. For this purpose, first of all, comprehensive discussions on the near wall flow complexities due to discharge of a jet into a crossflow are presented. In this regards, large scale coherent structures such as: counter rotating vortex pairs (CRVP's), near wall secondary motions, horseshoe vortices, and wall jets like are discussed. Secondly, the abilities of different turbulence models in predicting such flows (JICF) are evaluated. Our evaluation is based on three points of view including: 1) JICF characteristics, 2) computed location, and...
Jet-into-crossflow boundary-layer control: Innovation in gas turbine blade cooling
, Article AIAA Journal ; Volume 45, Issue 12 , May , 2007 , Pages 2910-2925 ; 00011452 (ISSN) ; Taeibi Rahni, M ; Darbandi, M ; Sharif University of Technology
2007
Abstract
Jet into crossflow has numerous technological applications, such as in film cooling of gas turbine blades. It has been more than half a century that people have been studying this problem and research is still underway due to its importance and its complexities. This paper is a computational study concerned with film cooling of gas turbine blades. A novel near-wall flow control technique of using staggered arrangement of small injection ports near a film-cooling hole (combined triple jet) is introduced. The fluid injected from the small ports changes the flow pattern downstream, resulting in a considerable enhancement of cooling efficiency. The flowfield computations, governed by the...
Developing a robust ordering-based unstructured moving grid strategy
, Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 24 , 2007 , Pages 17172-17184 ; 1563478900 (ISBN); 9781563478901 (ISBN) ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2007
Abstract
In this work, a new method is presented to control the propagation of the boundary deformation within an unstructured mesh domain effectively and to avoid inefficient and unnecessary grid movement computations. In this regard, a new and simple automatic unstructured mesh ordering strategy is developed. The mesh movement algorithm automatically determines the regions, which are affected by the displacement propagation. The method needs little memory storage benefiting from an improved mesh data structure. We also present an improved acceleration strategy, which is highly consistent with the modified connectivity matrix and is able to handle a wide variety of problems with small and large...
Jet into cross flow boundary layer control an innovation in gas turbine blade cooling
, Article 35th AIAA Fluid Dynamics Conference and Exhibit, Toronto, ON, 6 June 2005 through 9 June 2005 ; 2005 ; 9781624100598 (ISBN) ; Taeibi Rahni, M ; Darbandi, M ; Sharif University of Technology
2005
Abstract
New standpoint of turbulent coolant jets into crossflow, which have numerous applications in traditional and modern technology, especially in gas turbine blades, is presented in this work. It is more than half a century that, many researchers have been studying jet into cross flow to understand its behavior and to predict and control it better. Previous studies indicate that, the main attentions had been on: a- geometrical parameters such as: inclined and compound jet angles, hole's shape, jet's array arrangements, jet's spacing, and jet's channel depth, b- flow characteristics like: blowing ratio, density ratio, jet and cross flow Reynolds numbers, and turbulence intensity. Here, we have...
Parallelization of the Lattice Boltzmann model in simulating buoyancy-driven convection heat transfer
, Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; Volume 375, Issue 1 , 2004 , Pages 305-312 ; 02725673 (ISSN) ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2004
Abstract
The main objective of the current work is to utilize Lattice Boltzmann Method (LBM) for simulating buoyancy-driven flow considering the hybrid thermal lattice Boltzmann equation (HTLBE). After deriving the required formulations, they are validated against a wide range of Rayleigh numbers in buoyancy-driven square cavity problem. The performance of the method is investigated on parallel machines using Message Passing Interface (MPI) library and implementing domain decomposition technique to solve problems with large order of computations. The achieved results show that the code is highly efficient to solve large scale problems with excellent speedup. Copyright © 2004 by ASME
High gradient temperature thermo-buoyant flow in a square cavity with magnetoconvection using a novel non-boussinesq algorithm
, Article Numerical Heat Transfer; Part A: Applications ; Volume 64, Issue 3 , 2013 , Pages 255-272 ; 10407782 (ISSN) ; Hajibagheri, M ; Heidarnataj, M ; Darbandi, M ; Javaherdeh, K ; Sharif University of Technology
2013
Abstract
We study numerically the heat transfer of steady laminar flow in a square cavity filled with electrically conducting fluids, in the presence of an external uniform magnetic field. Imposing a large temperature gradient between two opposite vertical walls, there are substantial temperature and density variations in the domain. The fluid is treated as an ideal gas. Indeed, high temperature gradient thermo-buoyant cavity flows result in natural convection flow domains with high Rayleigh number. To implement the temperature variation effect, the fluid properties, including the conductivity and viscosity coefficients, are considered to vary with temperature in accordance to the Sutherland's law....
Combined model of mass-transfer coefficients for clean and contaminated liquid-liquid systems
, Article Industrial and Engineering Chemistry Research ; Volume 50, Issue 8 , 2011 , Pages 4608-4617 ; 08885885 (ISSN) ; Dehkordi, A. M ; Darbandi, M ; Shahalami, M ; Saien, J ; Sharif University of Technology
Abstract
Mass-transfer rates to and from drops in liquid-liquid extraction processes are often reduced by the presence of contaminants. To design an industrial extractor, it is essential to consider this contamination effect in a quantitative manner. To achieve this goal, an experimental investigation was conducted on the mass transfer into single drops for n-butanol-succinic acid-water, as the recommended test system by the European Federation of Chemical Engineering (EFCE). The effects of anionic (sodium dodecyl sulfate, SDS), cationic (dodecyl trimethyl ammonium chloride, DTMAC), and nonionic (octylphenol decaethylene glycol ether, Triton X-100) surfactants on the hydrodynamic and mass-transfer...
An open source, parallel DSMC code for rarefied gas flows in arbitrary geometries
, Article Computers and Fluids ; Volume 39, Issue 10 , 2010 , Pages 2078-2089 ; 00457930 (ISSN) ; Roohi, E ; White, C ; Darbandi, M ; Reese, J. M ; Sharif University of Technology
2010
Abstract
This paper presents the results of validation of an open source Direct Simulation Monte Carlo (DSMC) code for general application to rarefied gas flows. The new DSMC code, called dsmcFoam, has been written within the framework of the open source C++ CFD toolbox OpenFOAM. The main features of dsmcFoam code include the capability to perform both steady and transient solutions, to model arbitrary 2D/3D geometries, and unlimited parallel processing. Test cases have been selected to cover a wide range of benchmark examples from 1D to 3D. These include relaxation to equilibrium, 2D flow over a flat plate and a cylinder, and 3D supersonic flows over complex geometries. In all cases, dsmcFoam shows...
Entropy generation for compressible natural convection with high gradient temperature in a square cavity
, Article International Communications in Heat and Mass Transfer ; Volume 37, Issue 9 , November , 2010 , Pages 1388-1395 ; 07351933 (ISSN) ; Hasannasab, P ; Hosseinizadeh, S. F ; Darbandi, M ; Sharif University of Technology
2010
Abstract
Entropy generation due to heat transfer and fluid friction irreversibility has been investigated in a square cavity subjected to different side wall temperatures for compressible and incompressible natural convection flows. Based on the obtained velocity and temperature values, the distributions of local entropy generation, average entropy generation and average Bejan number are determined and compared for compressible and incompressible regimes. It is found that the entropy generated for compressible flow always is more than incompressible flow. The study is performed for Ra=10 4-10 8, j{cyrillic, ukrainian}=0.01(incompressible regime) and 0.6 (compressible regime), Ge=10 -5 and Pr=0.7
Numerical simulation of two-phase flow in airlift pumps using the Physical Influence Scheme
, Article Progress in Computational Fluid Dynamics ; Volume 10, Issue 3 , 2010 , Pages 186-194 ; 14684349 (ISSN) ; Saidi, M. H ; Darbandi, M ; Kebriaee, A ; Sharif University of Technology
2010
Abstract
A new approach has been presented to solve gas-liquid flow numerically in vertical pipes of air-lift pumps. To improve modelling, a new strategy has been employed with the capability of coupling the continuity and momentum equations and enforcing the role of pressure directly in the continuity equation. This is achieved via applying a novel scheme called the Physical Influence Scheme (PIS). The current finite volume solution is compared with other available numerical solutions. Indeed, they are in fair agreement. However, the present predictions are far superior to those obtained from an existing simple method, which is widely used in airlift pump modelling
Numerical simulation of two-phase flow in airlift pumps using the Physical Influence Scheme
, Article Progress in Computational Fluid Dynamics ; Volume 10, Issue 3 , 2010 , Pages 186-194 ; 14684349 (ISSN) ; Saidi, M. H ; Darbandi, M ; Kebriaee, A ; Sharif University of Technology
2010
Abstract
A new approach has been presented to solve gas-liquid flow numerically in vertical pipes of air-lift pumps. To improve modelling, a new strategy has been employed with the capability of coupling the continuity and momentum equations and enforcing the role of pressure directly in the continuity equation. This is achieved via applying a novel scheme called the Physical Influence Scheme (PIS). The current finite volume solution is compared with other available numerical solutions. Indeed, they are in fair agreement. However, the present predictions are far superior to those obtained from an existing simple method, which is widely used in airlift pump modelling
Computational investigation of graphene behavior under differential water pressure and possible mass transfer influences
, Article ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2016, 4 January 2016 through 6 January 2016 ; Volume 2 , 2016 ; 9780791849668 (ISBN) ; Darbandi, M ; Saidi, M.S ; Heat Transfer Division ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
Because of its unique properties, graphene has attracted the attentions of many academic research groups and recently, the industry. One of the promising applications of the graphene is in micro/nano-sensors, e.g. using it as a pressure sensor. To use it in mechanical-based nano-sensors, it is very important to investigate the mechanical behavior of the nano-sized graphene sheet and its sensitivity to the medium changes applied on its faces. In this work, we use the molecular dynamics MD method and simulate the behavior of graphene sheet under differential water pressure influences. In this regard, a square straight monolayer graphene sheet is placed as a separator diaphragm between two...
Physical aspects of rarefied gas flow in micro to nano scale geometries using DSMC
, Article 39th AIAA Fluid Dynamics Conference, 22 June 2009 through 25 June 2009, San Antonio, TX ; 2009 ; 9781563479755 (ISBN) ; Darbandi, M ; Mirjalili, V ; Schneider, G. E ; Sharif University of Technology
Abstract
Rarefied gas flow in micro/nano electro mechanical systems (MEMS/NEMS) does not perform exactly as that in macro-scale devices. The main goal in this study is to investigate mixed subsonic-supersonic flows in micro/nano channels and nozzles and to provide physical descriptions on their behaviors. We use DSMC method as a reliable numerical tool to extend our simulation. It is because the DSMC provides accurate solution for the Boltzmann equations over the entire range of rarefied flow regime or Knudsen numbers. As is known, the appearance of oblique/normal shocks at the inlet of a channel or a nozzle adds to the complexity of internal flow field analyses. We found some very unique physical...
Mass flow rate scaling of the continuum-based equations using information preservation method
, Article 41st AIAA Thermophysics Conference2009, Article number 2009-3746 ; 2009 ; 9781563479755 (ISBN) ; Darbandi, M ; Vakilipour, S ; Schneider, G. E ; Sharif University of Technology
Abstract
Kinetic theory based numerical scheme such as direct simulation Monte Carlo (DSMC) and information preservation (IP) schemes properly solve micro-nano flow problems in transition and free molecular regimes. However, the high computational cost of these methods encourages the researchers toward extending the applicability of the continuumbased equations beyond the slip flow regime. In addition to correct velocity profile, the continuum-based equations should predict accurate mass flow rate magnitude. The secondorder velocity slip models derived from the kinetic theory provide accurate velocity profiles up to Kn=0.5; however, they yield erroneous mass flow rate magnitudes because the basic...
Exhaust soot investigation in a JP combustor working at various wall temperatures
, Article AIAA Aerospace Sciences Meeting, 2018, 8 January 2018 through 12 January 2018 ; Issue 210059 , 2018 ; 9781624105241 (ISBN) ; Ghafourizadeh, M ; Darbandi, M ; Saidi, M. H ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2018
Abstract
In this study, a jet propulsion JP combustor is studied numerically to investigate the combustor wall temperature influences on the soot characteristics emitted at its exhaust. There are a number of ways to control the combustor wall temperatures benefiting from different wall cooling technologies. Irrespective of using different high technology cooling systems, it is important to recognize how the wall temperature can affect the soot emission from one specific JP engine. Before examining the main combustor, it is important to assess the accuracy of the computational fluids dynamics (CFD) tool via solving a benchmark problem. In this regard, the predicted flame structure for the benchmark...