01/16/2025
By Danielle Fretwell

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Doctoral Dissertation defense by Md Nayer Nasim on: "Assessing the Impact of Fuel/Working Fluid Combinations on Combustion Characteristics."

Candidate Name: Md Nayer Nasim
Degree: Doctoral
Defense Date: Thursday, Jan. 23, 2025
Time: 10 a.m. - Noon
Location: ETIC-445

Committee:
Advisor: John Hunter Mack, Associate Professor, Mechanical and Industrial Engineering, UMass Lowell

Committee Members*
1. Noah Van Dam, Assistant Professor, Mechanical and Industrial Engineering, UMass Lowell
2. Juan Pablo Trelles, Professor, Mechanical and Industrial Engineering, UMass Lowell
3. Dimitris Assanis, Assistant Professor, Department of Mechanical Engineering, Stony Brook University

Brief Abstract:
The combustion of hydrocarbon fuels is currently the primary power generation approach used in different transportation and energy production systems. With increasingly strict emission regulations and the depletion of conventional fossil fuel reserves, the search for alternative, cleaner sources of energy have become a priority for tackling environmental pollution and the global energy crisis. Hydrogen and ammonia are extremely attractive alternate fuels due to their inherent lack of carbon and potential compatibility with the existing transportation and power generation infrastructure. Unfortunately, due to diverging combustion characteristics in comparison to conventional fossil fuels such as natural gas, it is not feasible to simply use them as drop-in replacements in many applications such as internal combustion engines and gas turbines.

The purpose of this research is to evaluate multiple methods of flame speed manipulation of conventional fossil fuels and carbon-free alternatives inside an optically accessible constant volume combustion chamber (CVCC). Combustion characteristics of several fuel blends with different working fluids at multiple equivalence ratios and initial pressures are extensively analyzed in terms of laminar burning velocity, flame morphology, flame stability, peak pressure during combustion, and emissions. The emissions are analyzed using a Fourier Transform Infrared (FTIR) Spectroscopy system for detailed speciation (including NOx at ppm levels). A complementary computational approach was implemented in parallel with the experiments to validate the experimental results. Both the experimental and numerical approaches provided insight into the impact of various fuel and working fluid combinations on emissions.

While ammonia is largely viewed as a promising alternative fuel due to its lack of carbon, several issues need to be addressed prior to widespread adoption. In addition to infrastructure and materials compatibility, one particular risk is an increase in NOx and nitrous oxide emissions due to the fuel-bound nitrogen in ammonia molecules. A specific section of this research is dedicated to investigate the potential of reducing NOx emissions from ammonia combustion through staging. This includes two distinct ignition events at disparate conditions; typically, a primary zone that partially burns a fuel-air mixture prior to completing the combustion in a subsequent stage with the introduction of additional air. The method of altering working fluids was utilized again to facilitate the differentiation between fuel bound NOx and the thermal NOx generated from premixed combustion of ammonia by eliminating environmental nitrogen. Thus, this research will not only try to identify alternate fuel configurations suitable for existing applications but also contribute to lowering NOx emissions from future transportation and energy system.