Molecular Dynamics Simulations of Combustion Rates and Behaviors in Nanostructured Reactive Systems
Authors: Madison Rodriguez
Faculty Mentor: Douglas Spearot
College: Herbert Wertheim College of Engineering
Heterogeneous nanoparticle mixtures of appropriate chemistries have reactive capabilities. These systems provide high reactive diffusion followed by exothermic behavior; however, the role of changing system microstructure on combustion reaction rates is poorly understood. Thus, this work uses molecular dynamics simulations to study combustion in systems with nickel and aluminum nanoparticles uniformly heated from an external source to an ignition temperature, initiating a self-sustaining reaction. A MATLAB script is created to generate a randomized list of particle locations based on user input of number of particles, radius size, and nickel to aluminum ratio. The range of radii explored varies from 10 to 30 Angstroms, each with a system of 20 30 and 40 particles. Simulations are also evaluated with 30 particles of a 20 Angstrom radius ranging from 20% to 80% of aluminum.
Click the video below to view the student's poster pitch.
Great project! My understanding of reaction kinetics is at the macro level so it was interesting to learn about how it’s different at the nano scale. Your graphs and images are very well done and clearly illustrate the results. I’m curious to see how very small ratios, (such as <1% Nickel or <1% aluminum) affect the reaction rate and final temperature.
Thank you for reading! Very small ratio of one metal vs another would likely provide too little energy to effectively sustain the reaction. If the system is too large compared to the particles, they will not be close enough to diffuse and begin that exothermic reaction. Also, as long as a Ni particle is touching an Al particle (or is very close), it will react somewhat. But with very small amounts of just 1, it would take a very long time and likely not be enough energy to sustain to that higher final temperature range.
Wow, your findings of how differences in microstructure lead to different final temperatures and reaction rates are very interesting! Great job, Madison!
Thank you, Uzair!
Wow, Madison! This is so impressive! Great job explaining the significance of this project! Can you provide an example of an application where self-sustaining heat is required? Thank you!
Hey Daphne! Thank you so much! Self-sustaining heat is not always required, but it is favorable because it saves energy and money! So if we are manufacturing materials, and want to make a nickel-aluminum mixture, it is nice that they diffuse and mix by themselves with an ignition temperature, otherwise we would lose money and energy by consistently applying an external heat source to ensure that these particles mix together.
Some examples include manufacturing materials, military applications, and I’ve even seen self-sustaining reactions have a positive impact on drug production (favorable for energy efficiency)!
The poster looks really good, Maddie! The process seems extremely well-thought out. What are some real-world applications of this knowledge?
Hi Ashley! Thank you so much!
A lot of real-world applications include manufacturing capabilities and new material synthesis for use in other engineering fields. Combustion synthesis is incredibly energy efficient and saves companies and research labs some money. The mixing of the particles creates a new material that could have favorable properties if the microstructure is studied accurately. Other further applications can be used in the military, on drug production, and I’ve seen a lot of further study into nanoceramics with combustion synthesis (bio, electro, and magnetic nanoceramics have been the most popular and seemingly relevant.)
Well done Maddie. I enjoyed working with you this year.
Thank you, Dr. Spearot!
Hi Madison, great presentation. Is the synthesis of freestanding Ni and Al nanoparticles with radii of 2nm feasible with current processing techniques?
Hey David! Could you clarify the question?
Hi Madison, sorry for not being clear. Is it currently possible to reliably synthesize Ni and Al nanoparticles at the radii you simulated, or is this research something that would be utilized when processing techniques allow for 2nm Ni and Al nanoparticles?
Hey! The simulation software used (LAMMPS) was created so that researchers could accurately synthesize these reactions on a nanoscaled system. The smaller size allows for me to be more efficient with the timeline of this project. But physical research would likely utilize these small but accurate results to hypothesis and apply to a larger system.
And thank you very much!
The differences in results between 2nm and 3nm are very interesting! The data was very organized and I like your implementation of MATLAB and simulation work. Great research.
Hi Maddie!! You did a fantastic job explaining your research especially for someone like me who is not an engineer! Great and very impressive work!!
Hi Taylor! Thank you so much!