文档介绍：Analysis of High Load Turbine Blades at Low Re
Numbers with CFX-BladeGen Plus
H. Perez-Blanco
Penn State
Robert Van Dyken
Tom Mc Laughlin
Aaron Byerley
USAF Academy
Abstract
Gas turbine blades, especially those with high camber, exhibit flow separation in the suction side at part-
load conditions. These conditions may arise due to reduced power demand in stationary applications, or due
to flight at high altitudes. In the latter case, the reduced pounds the lower operating velocities
required to enhance range, and small trough-flows result in separation. When the inlet velocity is reduced
to the point that the flow is laminar, the flow in the suction side does not embody enough ic energy to
prevent flow reversal. Hence, a separation bubble takes place. The ensuing reduced blade effectiveness
results in losses that increase fuel consumption. It has been shown experimentally in cascades that the
inception and extent of separation are respectively a weak and strong function of the flow Reynolds no.
Also, cascade experimental data are available in the form of pressure and loss coefficients. The flow around
a highly loaded blade is modeled with CFX-BladeGen Plus. The insights thus gained regarding wake flow
and surface pressures are discussed in relation to data and conclusions afforded from other experimental
and analytical work. The experience with the predictive possibilities of numerical techniques regarding this
difficult problem, along with the benefits accrued via simulation are addressed.
Introduction
Some turbine blade designs exhibit suction side flow separation at part load conditions, which arise at
reduced power demand in stationary applications, or during flight at high altitudes. In the latter case, the
reduced pounds the lower operating velocities required to enhance range, and small trough-
flows result in separation, (Fig 1).
This phenomenon mon to many low-pressure, highly loaded blades (Bons (2