CAREER: Towards Understanding and Control of Surface-Impinging Particle-Laden Flows

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Gas flows laden with dispersed solid particles are generated in a variety of engineering applications where their interaction with material surfaces can lead to positive or negative outcomes. Positive outcomes include spray coatings and cold spray additive manufacturing, while negative outcomes include surface erosion and deposition affecting the performance of aircraft propulsion systems, wind turbines, and spacecraft in dusty atmospheres. Achieving control of the multiphase interaction process is limited by gaps in fundamental fluid dynamical understanding of momentum and energy transfer processes between the continuous gas phase and dispersed particles, which subsequently drives the interaction outcome between the particles and material surfaces. The PI will pursue an integrated research and education program to achieve three specific goals: 1) establish a connection between gas phase-influenced particle conditions and collision outcomes when the particles impact a solid surface, 2) use this connection to develop a control scheme to mitigate surface damage utilizing fluidic injection into the boundary layer, and 3) advance aerospace education through implementation of hands-on rocketry and aerodynamics courses for undergraduate and high-school students as well as a traveling exhibit on shockwave propagation aimed at the general public. The overall goal of this work is to address knowledge gaps pertaining to the critical role played by fluid dynamics in influencing surface impingement processes by particle-laden gas flows. Impulsively-accelerated single particles will be studied at controlled conditions in a shock tube setup, wherein, particle motion and temperature measurements will be used to study unsteady particle drag and heat transfer, and evaluate existing models for the same. Ultra-high-speed imaging of particle impact with a solid surface will be used to map collision outcomes to a regime map characterized by non-dimensional temperature and kinetic energy. Validation of the regime map and attempts to control surface damage through fluidic injection in the surface boundary layer will be pursued in a multiphase hot cascade setup generating continuous, particle-laden flow over an airfoil surface. The research program will serve as a platform for aerospace education through outreach activities including: a laboratory component on hybrid rockets incorporated into an undergraduate propulsion course, a mini-course on aerodynamics and propulsion for K-8 students, a middle-school summer research mentorship program, and an interactive shock wave demonstration incorporated into a traveling exhibit that visits schools and state fairs to further science education. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.