PROJECTS
Investigating Sand Transport in the Internal Cooling Passages of Turbine Blades
A simplified geometry, a U-shaped duct with square cross section, is considered in the present study to simulate a two pass internal cooling duct.
An effort is made to answer the following questions:
1. How do sand particles impinge the walls and ribs in a two pass duct?
2. Which regions in the two pass duct are most prone to erosion and deposition under prolonged sand ingestion?
Heat Transfer in a Two Pass Internal Cooling Duct with Rib Turbulators using Wall Modeled Large Eddy Simulations (WMLES)
This study presents turbulent flow and heat transfer predictions in a two pass cooling ribbed duct with 180 deg turn, using a zonal or two layer wall model. The boundary layer type equation are solved in the inner layer on a virtual grid, imbedded in outer LES grid and refined only in the wall normal direction.
Predicting Coefficient of Restitution for Particle Wall Collisions in Gas Turbine Components
This work presents a new model which predicts the energy losses and hence the coefficient of restitution for a particle-wall collision. This study combines elastic plastic deformation and adhesion theories of particle-wall interaction.Plastic deformation losses and adhesion losses are calculated separately based on impact parameters: impact velocity, impact angle, particle/wall material properties. These losses combine together to give the net energy loss during a collision and hence coefficient of restitution. The main objective of this study is to develop a collision model for sand particle interaction in gas turbine components, so the results are compared with available experimental data on coefficient of restitution for sand particles.
Developing Particle Sticking Models to Predict Sand Deposition in Gas Turbine Components
The objective of this study is to develop a particle sticking model based on energy losses and change in material properties at high temperatures. The study is novel in that it integrates different sources of published experimental data to form a holistic numerical model to predict sand deposition. The deposition model computes the sticking probabilities as a function of particle temperature, impact velocity and particle composition.
Predicting Transition over a NACA0012 Airfoil at 1 Million Reynolds Number using Wall Modeled Large Eddy Simulations
This work investigates the potency of a two layer or zonal wall model in LES to predict laminar to turbulent flow transition over a NACA0012 airfoil at 1 million Reynolds number. The governing equations for momentum and energy are discretized with a conservative finite-volume formulation using a second-order central (SOC) difference scheme on a non-staggered grid topology. The SOC discretization has minimal dissipation and has been shown to be suitable for LES computations. The two layer wall model is formulated by solving a reduced set of simplified equations in the inner wall region of boundary layer. The inner layer equations are solved on a virtual embedded grid along a normal between the first off-wall grid point (y+ <50) and the wall.
A Novel Flow System to Mimic Intracranial Hemodynamics
A flow chamber with converging and diverging sections is designed to expose cultured bovine aortic endothelial cells to positive and negative WSSGs. The chamber is designed such that effects of gradients at constant magnitude could be studied and simultaneously compared with zero gradient regions. The chamber was manufactured in the local machine shop. A flow system was designed for the chamber to replicate the physiological shear stress gradients in the endothelium to study the effects of positive and negative wall shear stress gradients. The designed flow system was used for multiple studies at Hemodynamics Lab., State University of New York, Buffalo.
Only few selected projects are presented on the website, more details available on request.