My research background for the last 25 years focuses predominantly gas turbine aerodynamics and heat transfer with the goal of improving turbine efficiency, reducing coolant flow, and modeling aerothermal performance of the technology enabling gas turbines for power and propulsion. That is where it started but I have since embarked on other areas of scholarship centered; my current research focus includes engineering education, sustainable development, and biomimicry.
Film Cooling is the single most important line of defense that allows turbine components to function in temperatures that exceed the melting point of the alloys. Film-cooling holes are machined through the surface of turbine airfoils, and coolant air is bled from cavities within the airfoil, through the film holes, to form a protective layer between the airfoil external surface and the hot gas. At high blowing ratios, the coolant can jet or blow off, allowing the hot gas to cover the surface, resulting in reduced effectiveness.
The nozzle guide vane (NGV) is a critical component of a gas turbine system. Its function is to accelerate and guide/turn the flow coming from the combustor and direct it to the blade row as smoothly as possible (i.e. with minimal aerodynamic losses). Flow through the NGV is highly complex and includes a multitude of physical phenomenon including: transition, separation, compressibility, mixing, unsteadiness, and heat transfer. Nozzle guide vanes are stationary blade rows that are exposed to the hottest gas temperatures from the combustor, which requires that it be aggressive cooled. The coolant interacts with the main flow and induces further aerodynamic losses in the stage.
The turbine blade or bucket poses some additional challenges compared to other hot gas path components because it rotates! And with that, comes windage effects and losses and concerns of the effect of the unsteadiness between the rotor/stator. This section highlights research on internal cooling of turbine blades as well as impingement cooling which is also an important method for internal cooling of nozzles and combustion liners.
As an educator for over 16 years, I have experimented with a lot of things in and out of the classroom. It became clear that experimentation isn’t enough without a pedagogical framework and assessment tools to evaluate the outcome of the changes I made. This section describes some of the research papers in engineering education in and out of the classroom.
Nature has solved a lot of design challenges including ones that humans currently face. Biomimicr
y learns from and mimics the strategies found in nature to solve human design challenges. Examples of biomimicry are found in many fields ranging from sustainable architecture inspired by termites to design of the bullet train inspired by king fisher’s beak.