About

Dr. Hooman V. Tafreshi is a faculty member in the Mechanical and Aerospace Engineering Department at NC State University and serves as the Associate Director for Research at the Nonwovens Institute. His research is in the field of thermo-fluids sciences at its interface with material science, with a particular focus on multiphase fluids and particle/droplet transport through fibrous materials. His work includes applications in filtration and separation sciences, as well as interfacial phenomena and droplet–surface interactions for self-cleaning and drag reduction applications. Prior to his current position, Dr. Tafreshi was with the Mechanical and Nuclear Engineering Department at Virginia Commonwealth University from 2007 to 2020, where he held roles as assistant, associate, and Qimonda full professor. He is an active member of the American Filtration and Separation Society and serves on the editorial board of the journal Separation and Purification Technology. His research activities are conducted through the Porous Media and Multiphase Flow Laboratory, which has published extensively in the field.

Research topics

• Materials science
• Composite material
• Physics
• Chemistry
• Chemical engineering
• Mechanics
• Nanotechnology
• Environmental science
• Chemical physics
• Chromatography
• Thermodynamics
• Condensed matter physics
• Environmental engineering

Selected publications

• Centrifugal Detachment of Compound Droplets from Fibers

  Langmuir · 2021 · 15 citations

  Senior authorCorresponding
  • Chemistry
  • Materials science
  • Composite material

  This article presents the first experimental–computational study on the centrifugal detachment of a compound droplet (e.g., a primary water droplet cloaked by an immiscible oil) from a fiber. The work was intended to establish a method for quantifying the force needed to detach compound droplets of different compositions from a fiber. More importantly, our study was aimed at improving the understanding of the interplay between interfacial and external forces acting on a compound droplet during forceful detachment. The experiments were conducted using DI water, for the primary droplet, and silicone or mineral oil, for the cloaking fluid. It was observed from the experiments that the silicone-oil-cloaked droplets behave differently from the mineral-oil-cloaked droplets. It was also observed that detachment force decreases with increasing the oil-to-water volume ratio. The simulations were performed using the Surface Evolver (SE) finite element code programmed for the complicated four-phase (air, water, oil, and solid) interfacial problem at hand. Our simulations revealed the evolution of the interfacial forces between the interacting phases under an increasing external body force on the droplet. The simulations also allowed us to define effective interfacial tensions and contact angles for detaching compound droplets, for the first time. Reasonable agreement was observed between the experimental measurements and computational results.

  DOI

• On liquid bridge adhesion to fibrous surfaces under normal and shear forces

  Colloids and Surfaces A Physicochemical and Engineering Aspects · 2020 · 34 citations

  Senior authorCorresponding
  • Materials science
  • Composite material
  • Mechanics
  DOI

• Performance of electrospun polystyrene membranes in synthetic produced industrial water using direct-contact membrane distillation

  Desalination · 2020 · 48 citations

  Senior authorCorresponding
  • Chemical engineering
  • Materials science
  • Chromatography

  Desalination of produced water in the gulf petrochemical industry is a continuing challenge to major research groups in the field. With a focus on produced water from desalination plants, it has become crucial to define and follow specific protocol in wastewater purification technologies. In this work, an optimized guideline for direct contact membrane distillation (DCMD) was developed and implemented. A bench-scale DCMD unit was performed under optimum process parameters of feed and distillation inlet temperatures of TFeed = 60 °C and TDist = 20 °C, respectively. A low flow rate of 0.03 L/min was used to avoid wetting of the fabricated membrane. A hydrophobic polystyrene flat sheet was prepared in the labs using a custom-made electrospinning apparatus. The effect of varying concentrations on the hydrophobic polystyrene membrane was studied using a high concentration brine feed (C1 ≈ 75,500 ppm) and another feed of lower concentration (C2 ≈ 25,200 ppm). A high salt rejection rate of 99% was achieved. The morphological structure, pore size and fiber length was analyzed using SEM. Conductivity measurements have confirmed an improved permeate quality of 99%. Thus, as per the DCMD performance of the polystyrene membrane, the generated permeate indicates that the membrane performance may have scalable potential contribution to industrial wastewater purification.

  DOI

Recent grants

• GOALI: Collaborative Research: Aerosol Droplets Migration in Fibrous Media

  NSF · $236k · 2014–2020

• Bimodal Nanofiber Mats with Controlled Microstructures for Size-Sensitive Nanoparticle Filtration/Separation and Superhydrophobic Drag Reduction

  NSF · $362k · 2010–2016

Frequent coauthors

• Behnam Pourdeyhimi

  141 shared

• S. Gautam

  North Carolina State University

  36 shared

• Amit Kumar

  36 shared

• Mohamed Gad‐el‐Hak

  34 shared

• S. Atri

  18 shared

• Mohamed A. Samaha

  Rochester Institute of Technology

  18 shared

• Mohammad Jamali

  Payame Noor University

  17 shared

• Gary Tepper

  Virginia Commonwealth University

  16 shared

Education

• PhD, Energy Technology

  Lappeenranta University of Technology

  1999

• MS, Mechanical Engineering

  University of Tehran

  1997

• BS, Mechanical Engineering

  KN Toosi University of Technology

  1995

Similar researchers at North Carolina State University

• Jonathan Lindseyh-101
• Edward Breitschwerdth-100
• José Alonsoh-94
• Rob Dunnh-94
• Frances S. Liglerh-92