Hasan Babaei
Postdoctoral Associate
Chemical & Petroleum Engineering, University of Pittsburgh
Mechanical Engineering, Carnegie Mellon University

3700 O'Hara St
940 Benedum Hall
Pittsburgh, PA 15261

email
C.V.
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Education       Research       Projects       Publications       In news       Links      

Education
Visiting Scholar, Mechanical Engineering, University of Illinois at Urbana-Champaign (2013-2014)
Ph.D., Mechanical Engineering, Auburn University (2009-2014)
M.Sc., Mechanical Engineering, University of Tehran (2006-2009)
B.Sc., Mechanical Engineering, Iran University of Science & Technology (2002-2006)


Research
Energy storage and conversion
Nanoscale transport phenomena
Nanostructured materials
Interface phenomena
Phase change materials
Nanoporous materials
Composites and colloidal suspensions
Molecular modeling


Projects


1) Heat and mass transfer in metal-organic frameworks
Metal-organic frameworks (MOFs), porous materials with extremely high internal surface areas, can adsorb large amount of gases and can be used for natural gas storage (e.g. in passenger vehicles). However, one challenge with MOFs is the heat generated during gas adsorption which leads to high temperatures, and in turn, prevents gas adsorption and reduces storage capacity. In principle, designing systems that could dissipate heat more quickly can allow for faster filling times. However, designing porous materials with better thermal properties requires a detailed understanding of the atomic-scale heat transfer mechanisms, which is still lacking in the literature. In this project, I use the adopted state-of-the-art molecular modeling approaches including MD, GCMC and SED calculations to study these systems and predict the needed thermal properties. During the past two years at Pitt and CMU, I have been studying the mechanisms of heat transfer in Metal-organic frameworks (MOFs) during gas adsorption using molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations and spectral energy density (SED) calculations.
H. Babaei , A. J. H. McGaughey and C. E. Wilmer, Effect of pore size and shape on the thermal conductivity of metal-organic frameworks, Chemical Science (2016).
H. Babaei and C. E. Wilmer, Mechanisms of Heat Transfer in Porous Crystals Containing Adsorbed Gases: Applications to Metal-Organic Frameworks, Physical Review Letters, 116, 025902 (2016). PRL Editors' Suggestion.
In news

2) Thermal transport in nanostructure-enhanced energy storage systems
One of the most convenient ways to store thermal energy is using phase change materials (PCM). PCM offer their sizeable latent heat for storing thermal energy at a constant temperature. However, a weakness of such materials is their relatively low thermal conductivity, which strongly suppresses the energy charge/discharge rates. A challenging option is to suspend highly-conductive particles into PCM, which produces "free-form" mixtures/composites. For PCM (here, paraffin), using molecular modeling, we found that introducing CNT and graphene sheets promotes aligning of the molecules in the direction parallel to the CNT axis and graphene surfaces, respectively and consequently leads to considerable enhancements in its thermal conductivity along those directions.
H. Babaei, P. Keblinski, and J. M. Khodadadi, Improvement in thermal conductivity of paraffin by adding high aspect-ratio carbon-based nano-fillers, Physics Letters A, 377, 1358-1361 (2013).
H. Babaei, P. Keblinski, and J. M. Khodadadi, Thermal conductivity enhancement of paraffin by increasing the alignment of molecules through adding CNT/Graphene, International Journal of Heat and Mass Transfer, 58, 209 (2013).

3) Low-dimensional thermoelectric materials
Energy conversion is one of the crucial components associated with effective utilization of renewable sources of energy. One of the most appropriate energy conversion approaches is the use of thermoelectric materials. Thermoelectric materials provide a direct way of converting waste heat and solar energy into electricity. For instance, they can be used to convert waste heat in vehicles into electricity. However, lack of an scalable source of thermoelectric materials having the required conversion efficiency has prevented commercializing these devices. One way to overcome the problem of low efficiency is to use low-dimensional materials. Recent developments in nanotechnology have made it possible to adjust the electrical and thermal properties of materials in such a way that they provide a higher amount of thermoelectric figure of merit. During my one-year stay at UIUC, by utilizing first principle and phonon calculations, I investigated the thermoelectric properties of single-layer molybdenum disulfide (SL-MoS2) (a 2-D material) and found an anomalously large thermoelectric power factor.
H. Babaei, J. M. Khodadadi, and S. Sinha, Large theoretical thermoelectric power factor of suspended single-layer MoS2, Applied Physics Letter 105, 193901 (2014).

4) Nanoscale heat transfer in nanofluids
In this work, the Green-Kubo method and equilibrium molecular dynamics (EMD) simulations were used for determining the thermal conductivity of nanofluids, which are highly inhomogeneous systems of solid nanoparticles suspended in liquids, and to elucidate the mechanism behind thermal conductance in such systems. I found that among different reported mechanisms of heat transfer in nanofluids, only clustering of nanoparticles can result in high enhancement in thermal transport. Even though the "nanofluid" publications have typically reported significant thermal conductivity enhancements for well-dispersed nanofluids, we showed that the Brownian motion-induced micro-convection can not lead to any significant enhancements.
H. Babaei, P. Keblinski, and J. M. Khodadadi, A Proof for Insignificant Effect of Brownian Motion-Induced Micro-Convection on Thermal Conductivity of Nanofluids by Utilizing Molecular Dynamics Simulations, Journal of Applied Physics, 113, 084302 (2013).
H. Babaei, P. Keblinski, and J. M. Khodadadi, Equilibrium molecular dynamics determination of thermal conductivity for multi-component systems, Journal of Applied Physics, 112, 054310 (2012).

5) Effect of nanoparticles on thin film lubrication
In this project, I used Molecular Dynamics simulations to investigate the effect of presence of a nanoparticle on thin film lubrication. The project was aimed to explain the experimentally-observed enhancing effect of nanoparticles on rheological properties of complex fluids. I showed that adding nanoparticles into the base fluid stimulates a plug flow, which leads to shearing over a few layers of lubricant's molecules on top and bottom of nanoparticles. Occurrence of plug flow results in the reduction in the coefficient of friction.
H. Ghaednia, H. Babaei, R. L. Jackson, M. J. Bozack, J. M. Khodadadi, The effect of nanoparticles on thin film elasto-hydrodynamic lubrication, Applied Physics Letters, 103(26), 263111 (2013).

6) Modeling of turbulent vortex shedding flow around a square cylinder near a wall
In this project, firstly, I studied two-dimensional and unsteady RANS computations of time dependent, periodic, turbulent flow around a square block. Secondly, I studied the turbulent vortex shedding flow around a square cylinder in various distances of a wall and the effects of wall proximity on the flow. Based on the gap distance between cylinder and wall (G), various vortex shedding behaviors were observed. When the cylinder is placed far from the wall (G/D=4, D is the square side length) vortices shed regularly and symmetrically from both upper and lower sides of the cylinder. When the cylinder approaches to the wall (G/D=0.75), vortex structure changes and, consequently, Strouhal number decreases. The vortices shed from the lower side of cylinder are elongated and weakened while the ones shed from the upper side are formed in higher points relative to the cylinder. By further displacement of the cylinder towards the wall (G/D=0.6, 0.5 and 0.4), the unsteadiness of the flow was not observed in a complete form anymore and regular vortex shedding did not occur. By moving the cylinder closer to the wall, from a critical distance (around G/D=0.25), the flow was found to be steady and vortex shedding was completely suppressed.
M. Raisee, A. Jafari, H. Babaei and H. Iacovides, Two-Dimensional Prediction of Time-Dependent, Turbulent Flow around a Square Cylinder Confined in a Channel, International Journal for Numerical Methods in Fluids, 62, 1232 (2010).



Publications

Papers to be submitted

  1. H. Babaei, A. J. H. McGaughey and C. E. Wilmer, Transient molecular simulation of gas adsorption into metal-organic frameworks: heat and mass transfer phenomena, to be submitted.
  2. H. Babaei, A. J. H. McGaughey and C. E. Wilmer, Heat Transfer in Porous Crystals, to be submitted.
  3. H. Babaei, J. M. Khodadadi, and S. Sinha, Phonon relaxation times for single-layer MoS2 from ab initio calculations, under progress.
  4. H. Babaei and M. Raisee, Modeling of Vortex Shedding Turbulent Flow around a Square Cylinder near a Wall, to be submitted.

Journal publications

  1. H. Babaei , A. J. H. McGaughey and C. E. Wilmer, Effect of pore size and shape on the thermal conductivity of metal-organic frameworks, Chemical Science (2016).
  2. H. Babaei and C. E. Wilmer, Mechanisms of Heat Transfer in Porous Crystals Containing Adsorbed Gases: Applications to Metal-Organic Frameworks, Physical Review Letters, 116, 025902 (2016). PRL Editors' Suggestion.
  3. H. Babaei, J. M. Khodadadi, and S. Sinha, Large theoretical thermoelectric power factor of suspended single-layer MoS2, Applied Physics Letter 105, 193901 (2014).
  4. R. L. Jackson, H. Ghaednia, H. Babaei, J. M. Khodadadi, Comment on Sperka, P., I. Krupka, M. Hartl (2014)."Evidence of Plug Flow in Rolling-Sliding Elastohydrodynamic Contact.", Tribology Letters 54 (2), 151-160 (2014).
  5. H. Ghaednia, H. Babaei, R. L. Jackson, M. J. Bozack, J. M. Khodadadi, The effect of nanoparticles on thin film elasto-hydrodynamic lubrication, Applied Physics Letters, 103(26), 263111 (2013). *The first two authors contributed equally to this work*.
  6. J. M. Khodadadi, Liwu Fan and H. Babaei, Thermal Conductivity Enhancement of Nanostructure-Based Colloidal Suspensions Utilized as Phase Change Materials for Thermal Energy Storage: A Review, Renewable & Sustainable Energy Reviews, 24, 418 (2013).
  7. H. Babaei, P. Keblinski, and J. M. Khodadadi, Improvement in thermal conductivity of paraffin by adding high aspect-ratio carbon-based nano-fillers, Physics Letters A, 377, 1358-1361 (2013).
  8. H. Babaei, P. Keblinski, and J. M. Khodadadi, Thermal conductivity enhancement of paraffin by increasing the alignment of molecules through adding CNT/Graphene, International Journal of Heat and Mass Transfer, 58, 209 (2013).
  9. H. Babaei, P. Keblinski, and J. M. Khodadadi, A Proof for Insignificant Effect of Brownian Motion-Induced Micro-Convection on Thermal Conductivity of Nanofluids by Utilizing Molecular Dynamics Simulations, Journal of Applied Physics, 113, 084302 (2013).
  10. H. Babaei, P. Keblinski, and J. M. Khodadadi, Equilibrium molecular dynamics determination of thermal conductivity for multi-component systems, Journal of Applied Physics, 112, 054310 (2012).
  11. M. Raisee, A. Jafari, H. Babaei and H. Iacovides, Two-Dimensional Prediction of Time-Dependent, Turbulent Flow around a Square Cylinder Confined in a Channel, International Journal for Numerical Methods in Fluids, 62, 1232 (2010).

Conference publications and presentations

  1. H. Babaei and Christopher E. Wilmer, Heat Transfer in Porous Crystals Containing Adsorbed Gases, Bulletin of the American Physical Society 2016.
  2. H. Babaei, J. M. Khodadadi, and Sanjiv Sinha, Relaxation Times of Single-Layer MoS2, MRS Spring 2015.
  3. Krishna V. Valavala, H. Babaei and Sanjiv Sinha, Thermoelectric Power Factor Measurement on Monolayer MoS2, presented at MRS Spring 2015.
  4. H. Babaei and Christopher E. Wilmer, Heat Transfer Mechanisms in Metal-Organic Frameworks during Natural Gas Storage Adsorption, MRS Spring 2015.
  5. H. Babaei, J. M. Khodadadi, and Sanjiv Sinha, Phonon Relaxation Times and Thermoelectric Properties of Single-Layer MoS2, MRS Spring 2014.
  6. H. Babaei, P. Keblinski, and J. M. Khodadadi, Molecular dynamics study of the interfacial thermal conductance at the graphene/paraffin interface in solid and liquid phases, ASME HT2013.
  7. H. Ghaednia,H. Babaei, R.L. Jackson, M. J. Bozack, J. M. Khodadadi, The Effect of Nanoparticle Additives in the Elasto-hydrodynamic Lubrication Regime, 68th Annual Meeting and Exhibition of the Society of Tribologists and Lubrication Engineers (STLE 2013), 5-9 May, Detroit, MI.
  8. H. Ghaednia,H. Babaei, R.L. Jackson, M. J. Bozack, J. M. Khodadadi, The Effect of Nanoparticle Additives in the Elasto-hydrodynamic Lubrication Regime, Tribology and Lubrication Technology (TLT), Dec 2013, STLE.
  9. H. Babaei, Thermal conductivity enhancement of paraffins by increasing the alignment of molecules through adding CNT/Graphene, LAMMPS workshop, Aug 6-8, 2013.
  10. H. Babaei, P. Keblinski, and J. M. Khodadadi, Thermal conductivity enhancement of paraffin by increasing the alignment of molecules through adding CNT/Graphene, 49th Annual Technical Meeting of the Society of Engineering Science, Oct. 12-14, 2012.
  11. H. Babaei, Prediction of Thermal Conductivity of Colloidal Suspensions via Molecular Dynamics Simulations, LAMMPS workshop, Aug 9-11, 2011.
  12. H. Babaei and J. M. Khodadadi, Prediction of Thermal Conductivity of a Model Nanofluid via Molecular Dynamics Simulations, Thermal and Materials Nanoscience and Nanotechnology, Antalya, Turkey, May 29 - June 3, 2011.
  13. H. Babaei and J. M. Khodadadi, Prediction of Thermal Conductivity of Liquid Methane/Ethane-Cu Nanofluids via Molecular Dynamics Simulations, TechConnect World Conference and Trade Show, June 13-16, 2011, Boston, Massachusetts, U.S.A.
  14. H. Babaei and M. Raisee, Simulation of Turbulent Flow around a Square Cylinder Near a Wall, 12th Annual Int. Conf. Fluid Dynamics, Iran, 2008.
  15. H. Babaei and M. Raisee, Modeling of Vortex Shedding Turbulent Flow around a Square Cylinder near a Wall, Turbulence, Heat and Mass Transfer Conference, Italy, 2009.
  16. H. Babaei and Gh. Atefi, Analysis of Turbulent Flow through a Channel using 2nd and 3rd Grade Fluids, 14th Annual Int. Conf. on Mech. Eng., Isfahan University of Technology, Iran (In Persian), May 2006.



In news

News release about the work on heat transfer in metal-organic frameworks:
United Press International
phys.org
Science Codex
EurekAlert
NGT News
Tribune Review
ScienceDaily
nano werk
ECN news
Materials Gate
Big News Network
AZoM: Materials Science and Engineering Information
Pitt Swanson Engineering
Chem Europe

Auburn University Distinguished Dissertation Award:
Auburn Graduate School
College of Engineering



Theses
Ph.D.: "Molecular-Level Modeling of Thermal Transport Mechanisms within Carbon Nanotube/Graphene-based Nanostructure-Enhanced Phase Change Materials"
Advisors: Professor Jay M. Khodadadi and Professor Pawel Keblinski
Auburn University, 2014.

M.Sc.: "Simulation of Turbulent Vortex Shedding Past a Square Cylinder near a Wall"
Advisor: Professor Mehrdad Raisee
University of Tehran, 2009.

B.Sc.:  "Analysis of Turbulent Flow through a Channel using 2nd and 3rd Grade Fluids"
Advisor: Professor Gholamali Atefi
Iran University of Science & Technology, 2006.


Journal reviewer
ACS Nano
Physical Chemistry Chemical Physics
ACS Applied Materials and Interfaces (3 manuscripts)
Journal of Applied Physics (7 manuscripts)
Applied Physics Letters (2 manuscripts)
Advanced Materials
Composites Science and Technology
Carbon (2 manuscripts)
International Journal of Heat and Mass Transfer
Journal of Heat Transfer
Chemical Engineering Science
Solar Energy Materials and Solar Cells
Journal of Renewable and Sustainable Energy
Materials
Energy Technology
Solar Energy
Journal of Computational Electronics


Links
The Hypothetical Materials Lab at University of Pittsburgh
Nanoscale Transport Phenomena Laboratory at Carnegie Mellon University
Nanostructure-Enhanced Phase Change Materials at Auburn University
Nanoscale Elctro-Thermal Transport, Conversion & Storage at University of Illinois at Urbana-Champaign


IP Address