About

Tiegang Fang is a Professor in the Department of Mechanical and Aerospace Engineering at NC State University. He arrived at NC State in 2007 and has developed courses such as Advanced Engine Combustion and Automotive Power Systems, which incorporate videos and experimental design to help students visualize flow and combustion behavior. His research focuses on improving the environment and reducing energy needs through the advancement of clean combustion technologies. His interests include combustion, internal combustion engines, exhaust emissions, air pollution control, alternative fuels, spray and atomization, droplet impact, laser diagnostics for reacting flows, energy conversion systems, heat and mass transfer, and fluid mechanics. Dr. Fang's work is notable for its societal relevance, hands-on approach, and the use of high-speed cameras and laser diagnostic methods to observe combustion processes inside engines. He actively mentors students, setting clear goals and providing close guidance and feedback in the lab.

Research topics

• Materials science
• Chemistry
• Mechanics
• Thermodynamics
• Organic chemistry
• Physics
• Environmental chemistry
• Automotive engineering
• Mathematics
• Mechanical engineering
• Chemical physics
• Geometry
• Nanotechnology
• Composite material
• Classical mechanics

Selected publications

• Generation of micro-blood droplets and their impact on various surfaces

  Review of Scientific Instruments · 2026-03-01

  articleSenior author

  In this paper, an experimental setup for successful generation of single micro blood droplets is reported and preliminary investigations on the formation of micro droplets and micro droplet impact dynamics are presented. An optimal operating range is identified for the stable generation of single blood droplet in the droplet-on-demand (DoD) mode. By raising the local relative humidity around the tip of the piezoelectric dispensing nozzle, a single blood droplet can be generated in the DoD mode without clogging for a long operation time. The influence of pulse width on the generation of micro blood droplets has been studied and an optimal operation region for generating single micro blood droplet has also been identified. The surface wettability is found to affect the maximum spread factor and post-impact oscillation of an impacting micro blood droplet. The influence of the surface wettability becomes weaker with an increasing Weber number, We. The variation of the maximum spread factor for a millimeter-sized blood droplet follows a trend similar to that for a micro blood droplet on silicon and Teflon surfaces (advancing contact angle θa > 90°) but not on the glass surface (θa < 90°). Micro bloodstains on the glass surface exhibit zonal characteristics similar to the macro-sized bloodstains. The blood cells can be clearly identified in the central part of the micro bloodstain. The bloodstain on the Plain Woven fabric surface basically stays on the top of a yarn without saturating too much space within it due to the tiny amount of the micro blood droplet and the comparable size of the yarn.

  PublisherDOI

• Capturing Carbon Dioxide (CO2) and Synthetization of Hydrocarbon Fuels from Captured CO2: A Brief History, Processes, and Environmental Consequences

  2026-01-01

  articleOpen accessSenior author
  PublisherDOI

• Spray characteristics of flash-boiling hollow-cone liquid ammonia sprays under direct injection conditions

  Physics of Fluids · 2026-01-01 · 1 citations

  articleSenior author

  Ammonia, a carbon-free compound, holds significant potential as a fuel in internal combustion engines. Recent research has revealed the limitations of gaseous ammonia use and highlighted the need to inject it in the liquid phase at higher pressures into the combustion environment to mitigate these shortcomings. This study focuses on investigating the flash-boiling effects of high-pressure liquid ammonia spray in a constant volume combustion chamber (CVCC) using a hollow-cone gasoline direct injection injector. Based on high-speed Schlieren and shadowgraph imaging data, the spray characteristics under varying ambient conditions are characterized. In particular, parameters such as the spray cone angle, penetration length, and plume ratios are studied to characterize the transformation of liquid ammonia spray into different spray regimes, characterized by flash-boiling phenomena. Furthermore, this work establishes a correlation between an increase in the ambient temperature of the CVCC and the transition into different regimes, as evidenced by the characteristics of the spray plume. Furthermore, the cooling effects of high fuel injection pressures at elevated CVCC ambient pressures are investigated to study the impact of pressure differentials on the drop in temperature caused by the injection of liquid ammonia. The findings of this study can serve as a foundation for the development of high-pressure liquid ammonia direct injection techniques, leveraging the rapid flash-boiling behavior of liquid ammonia.

  PublisherDOI

• Computational Study of Hybrid Propeller Configurations

  Aerospace · 2026-01-15

  articleOpen accessSenior author

  This study presents the first computational investigation of hybrid propeller configurations that combine toroidal and conventional blade geometries. Using Delayed Detached Eddy Simulation (DDES) with the Shear Stress Transport (SST) k−ω model for flow analysis and the Ffowcs Williams and Hawkings (FW–H) formulation for aeroacoustic prediction, five hybrid propeller designs were evaluated: a baseline model and four variants with modified loop-element spacing. The results show that the V-Gap-S configuration achieves the highest figure of merit (FM), producing over 10% improvement in propeller performance relative to the baseline, while also exhibiting the lowest turbulence kinetic energy (TKE) levels across multiple radial planes. Aeroacoustic analysis reveals quadrupole-like directivity for primary tonal noise, primarily driven by blade tip–vortex interactions, with primary tonal noise strongly correlated with thrust. Broadband noise and overall sound pressure level (OASPL) exhibited dipole-like patterns, influenced by propeller torque and FM, respectively. Comparisons of surface pressure, vorticity, and time derivatives of acoustic pressure further elucidate the mechanisms linking blade spacing to aerodynamic loading and noise generation. The results demonstrate that aerodynamic performance and aeroacoustics are strongly coupled and that meaningful noise reduction claims require performance conditions to be matched.

  PublisherDOI

• Experimental and Numerical Study of a UAV Propeller Printed in Clear Resin

  Aerospace · 2025-04-22 · 5 citations

  articleOpen accessSenior author

  This paper presents an experimental and numerical investigation of a 254 mm resin-printed propeller operating at rotational speeds between 3000 and 9000 RPM. Propeller thrust and torque were measured using a six-degree-of-freedom load cell, while acoustic data were captured with a microphone positioned three times the propeller diameter from the center. To complement the experimental analysis, computational simulations were conducted using ANSYS Fluent with the detached eddy simulation (DES) model, the Ffowcs-Williams and Hawkings (FW-H) model, and a transient flow solver. The figure of merit (FM) results show that the resin propeller slightly outperforms two commercial counterparts with a marginal difference between the wood and resin propellers. Additionally, the resin propeller demonstrates better noise performance, exhibiting the lowest primary tonal noise, broadband noise, and overall sound pressure level (OASPL), with minimal differences between the two commercial counterparts. ANSYS Fluent simulations predict thrust and torque within a 10% error margin, showing particularly accurate results for primary tonal noise. A new trade-off index is proposed to assess the balance between propeller performance and aeroacoustics, revealing distinct trends compared to traditional metrics. Furthermore, aerodynamic phenomena such as flow separation on the leading edge near the tip, flow separation behind the middle trailing edge, and vortex interactions at the root are identified as key contributors to tonal and broadband noise. These findings provide valuable insights into propeller design and aeroacoustic optimization.

  PublisherDOI

• Experimental investigation of emission characteristics and combustion performance of sustainable aviation fuel in a swirl combustor with varying vane angles

  Applied Thermal Engineering · 2025-11-30

  articleSenior author
  PublisherDOI

• Synthesis of hafnium carbide (HfC) via one‐step selective laser reaction pyrolysis from liquid polymer precursor

  Journal of the American Ceramic Society · 2025-05-14 · 7 citations

  articleOpen accessCorresponding

  Abstract This study introduces a novel one‐step selective laser reaction pyrolysis (SLRP) method for synthesizing hafnium carbide (HfC), an ultrahigh‐temperature ceramic (UHTC). Unlike conventional methods that involve multiple steps, including crosslinking and pyrolysis, this approach combines both processes into a single laser‐driven step, reducing time and energy consumption. The CO 2 infrared (IR) laser ( λ = 10.6 µm) used in this technique enables localized heating up to 2000°C within seconds, facilitating the conversion of a liquid polymer precursor into HfC. Material characterization using x‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the crystallinity and phase purity of the synthesized HfC powder. To study energy absorption, thermal and photo‐activators were added to the precursor before laser exposure. The thermal activator had a negligible impact on reflectivity but yielded a pure HfC phase, demonstrating the potential for optimized precursor formulations to enhance efficiency without compromising purity. The one‐step process was successfully applied for additive manufacturing, depositing HfC coatings onto carbon–carbon (C/C) composite substrates. This technique eliminates the need for high‐temperature furnaces, enabling rapid fabrication of UHTC components and advancing scalable, energy‐efficient manufacturing. The study highlights its potential for energy, aerospace, and other extreme environment applications.

  PublisherOA PDFDOI

• Use of Methanol in a High-Power Density Generator

  SAE International journal of sustainable transportation, energy, environment & policy · 2025-04-02

  articleSenior author

  &lt;div&gt;Increasing global pressure to reduce anthropogenic carbon emissions has inspired a transition from conventional petroleum-fueled internal combustion engines to alternative powertrains, including battery electric vehicles (EVs) and hybrids. Hybrids offer a promising solution for emissions reduction by addressing the limitations of pure EVs such as slow recharge and range anxiety. In a previous research endeavor, a prototype high-power density generator was meticulously designed, fabricated, and subjected to testing. This generator incorporated a compact permanent magnet brushless dynamo and a diminutive single-cylinder two-stroke engine with low-technology constructions. This prototype generated 8.5 kW of electrical power while maintaining a lightweight profile at 21 kg. This study investigates the performance and emissions reduction potential by adapting the prototype to operate on methanol fuel. Performance and emissions were experimentally evaluated under varying operating conditions. In addition, a comparative analysis between methanol fuel and conventional gasoline was performed. It was found that the generator operable on methanol achieved an overall increase in performance with a peak power output of 10 kW when compared to gasoline. In addition, the generator demonstrated significant reductions in carbon emissions. The goal of this research is to adapt and demonstrate the high-power density, low-emission electric power generator from previous work, which was suitable for applications such as, for example, range extenders and UAV propulsion, to use renewable fuel. This research showcases a potential direction for an electrical generator that offers reduced emissions in applications where specific power is critical.&lt;/div&gt;

  PublisherDOI

• Dynamics of blood falling on three types of cotton fabrics and resulting bloodstains

  Forensic Science International · 2025-06-23 · 1 citations

  articleSenior authorCorresponding
  PublisherDOI

• Experimental and Numerical Analysis of a Toroidal Propeller

  Journal of Aerospace Engineering · 2025-08-23 · 3 citations

  articleSenior author

  This study presents an experimental and numerical analysis of a 254 mm toroidal propeller, focusing on its aerodynamic performance and acoustic characteristics. Experiments were conducted in an anechoic chamber, where a load cell and microphones captured propeller performance and aeroacoustic data. The propeller achieves a figure of merit of approximately 0.45, indicating moderate efficiency. Pressure differentials near the blade tips are identified as the primary contributors to thrust and torque, with the leading blade in a single loop reducing lift on the trailing blade by up to 50%. Vortex structures in the propeller’s slipstream, including root, tip, and central vortices, are analyzed, and curve-fitting techniques are used to model tip vortex trajectories at various rotational speeds. The Spalart–Allmaras model, coupled with the Ffowcs-Williams and Hawkings model in Reynolds-averaged Navier–Stokes equations, accurately predicts tonal noise but underestimates broadband noise and the overall sound pressure level (OASPL) due to its tendency to smooth out pressure fluctuations. A comparison with conventional advanced precision composite and wood propellers shows that the primary tonal noise, broadband noise, and OASPL increase with disk loading, underscoring the importance of consistent test conditions when comparing toroidal propellers with conventional designs. Overall, the study provides valuable insights into the performance characteristics of toroidal propellers and offers recommendations for future research.

  PublisherDOI

Recent grants

• Variable Geometry Spray Fuel Injection: Investigating its Effects on Combustion Efficiency and Emissions

  NSF · $330k · 2009–2012

Frequent coauthors

• William L. Roberts

  King Abdullah University of Science and Technology

  35 shared

• Kaushik Nonavinakere Vinod

  North Carolina State University

  22 shared

• Chia-fon F. Lee

  University of Illinois Urbana-Champaign

  16 shared

• Robert E. Coverdill

  University of Illinois Urbana-Champaign

  15 shared

• Robert A. White

  Saudi Aramco (United States)

  15 shared

• Fujun Wang

  15 shared

• Yongfang Zhong

  14 shared

• Balaji Mohan

  Saudi Aramco (Saudi Arabia)

  12 shared