Accession Number:

ADA083766

Title:

Time-Variant Aerodynamics for Torsional Motion of Large-Turning Airfoils.

Descriptive Note:

Final rept.,

Corporate Author:

GENERAL MOTORS CORP INDIANAPOLIS IN DETROIT DIESEL ALLISON DIV

Report Date:

1980-01-01

Pagination or Media Count:

109.0

Abstract:

A cascade of five airfoil sections modelling the hub section of an advanced design turbine featuring a high inlet Mach number and 112 degrees of turning was evaluated at 4 steady-state conditions of varying exit Mach number and expansion ratio. The resulting steady-state airfoil surface pressures were compared to a state-of-the-art analytical prediction. A time-variant investigation was conducted at the 4 operating conditions of the steady-state experiment. Time-variant pressure signals were obtained from a Kulite-instrumented airfoil as the cascade was torsionally oscillated at four values of interblade phase angle per expansion ratio by computer-controlled electromagnetic drive systems. The dynamic pressure signals were evaluated in amplitude and phase lag referenced to blade motion and correlated with a state-of-the-art analytical prediction based on a flat-plate cascade. A quasistatic experiment was performed to relate the dynamic surface pressure amplitudes to those obtained by resetting the cascade to various temporal positions in the torsional cycle of oscillation. Author

Subject Categories:

  • Fluid Mechanics
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE