CFD analysis of low pressure turbine blade using vortex generator jets
With the trend toward higher bypass ratios in turbofans, demands are increasing for the low pressure turbines (LPT) that drive the large fan assemblies. Also, many military and civilian applications use the LPT to power an ever increasing applications of onboard communication, diagnostic, and service hardware. Aerodynamic efficiency is a major concern in today's aerospace and aircraft industries. But the flow separation is one of the important factors that affect the aerodynamic efficiency. At very high altitudes the low Reynolds number flow through the low pressure turbine section of the gas turbine engine can drop below 25,000. At these low Reynolds numbers the flow is laminar and extremely susceptible to separation which can lead to increased losses and reduced lift. Small jets of air injected through the suction surface of the airfoil, called Vortex Generator Jets (VGJs), have been shown successful in suppressing separation and maintaining attached flow. We focused on designs of Low Pressure Turbine with the available L1A blade data to improve the performance of the aircraft, delay boundary layer separation and increase the lift forces and to analyze the performance of the turbine blade with vortex generator jet with the available fluent software. We conclude that flow separation can delayed by using vortex generator.
Parametric Study of Vortices Shed from Airfoil Vortex Generators
Extensive parametric study of vortices shed from the tips of airfoil vortex generators has been conducted to determine the dependence of initial vortex circulation and peak vorticity on elements of airfoil geometry and impinging-flow conditions. The vortex generators were symmetric airfoils examined in subsonic airflow on the surface of a straight pipe. The circulation and peak-vorticity data were derived from cross-plane velocity measurements acquired with a seven-hole probe one chord length downstream of the airfoil-trailing-edge-tip location. Circulation and peak vorticity are observed to be proportional to the freestream Mach number, the angle of attack, and the span-to-boundary-layer-thickness ratio
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.