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.
Control of low-speed turbulent separated flow using jet vortex generators
A parametric study has been performed with jet vortex generators to determine their effectiveness in controlling flow separation associated with low-speed turbulent flow over a two-dimensional rearward-facing ramp. Results indicate that flow-separation control can be accomplished, with the level of control achieved being a function of jet speed, jet orientation (with respect to the free-stream direction), and jet location (distance from the separation region in the free-stream direction). Compared to slot blowing, jet vortex generators can provide an equivalent level of flow control over a larger spanwise region (for constant jet flow area and speed).
The NASA Lewis Research Center Internal Fluid Mechanics Facility
An experimental facility specifically designed to investigate internal fluid duct flows is described. It is built in a modular fashion so that a variety of internal flow test hardware can be installed in the facility with minimal facility reconfiguration. The facility and test hardware interfaces are discussed along with design constraints of future test hardware. The plenum flow conditioning approach is also detailed. Available instrumentation and data acquisition capabilities are discussed. The incoming flow quality was documented over the current facility operating range. The incoming flow produces well behaved turbulent boundary layers with a uniform core. For the calibration duct used, the boundary layers approached 10 percent of the duct radius. Freestream turbulence levels at the various operating conditions varied from 0.64 to 0.69 percent of the average freestream velocity.