2.4.2 Highly Loaded Compressor Blades

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2.4.2 Highly Loaded Compressor Blades
2.4 Intelligent Engine Systems
Sankar (Ga Tech)

• Approach Collaborators (Prasad, Dunn
  Neumeier)
• A first-principles based CFD methodology will
  used to detect precursor events leading to stall
  and surge.
• A variety of passive and active control
  strategies will be systematically explored
  upstream injection, inter-stage bleeding, passive
  devices such as slotted airfoils, and circulation
  control of stator vanes aimed at altering the
  flow direction.
• Comparisons will be made with measurements, where
  available. Control laws will be developed jointly
  with our collaborators, and tested.

• Motivation/Relevance to NASA Goals

• Motivation
• Next generation compression systems will have
  high pressure rise per stage, and will operate
  closer to stall line than existing systems.
• Active and passive control strategies are needed
  to achieve this loading, without experiencing
  rotating stall, surge, and other instabilities.
• A combined experimental, analytical, and
  computational research on effective means of
  controlling compressor instabilities is needed.
• This task deals with computational efforts.

• Relevance
• High pressure ratios are important for reducing
  the number of stages in an engine, with attendant
  reductions in engine weight and size.
• Conventional approaches for engine control rely
  on inter-stage bleeding, which reduces the
  efficiency of the system.
• Research on efficient ways of controlling
  instabilities is needed for ensuring the safe
  operation of these systems.

• Schedule (First two years)
• Lead L. Sankar
• Support/Collaborators Prasad, Dunn, Neumeier
• No. of Students 1
• Selection of configuration and operating
  conditions
• Development of performance map
• Preliminary computations for rotors with slotted
  airfoils.

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2.4.2 Background
Motivation and Objectives

• Use CFD to explore and understand compressor
  stall and surge
• Develop and test passive (slotted airfoils) and
  active control strategies (circulation-controlled
  stator vanes) for centrifugal and axial
  compressors.

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2.4.2 Proposed Approach

• The performance map of representative axial
  compressor configurations will be constructed
  using a 3-D compressible Navier-Stokes solver
  developed by the present investigators.
• Leading edge and trailing edge stall alleviation
  will be investigated with the use of slotted
  airfoils for these configurations. Performance
  penalties at off-design conditions will be
  assessed.
• Trailing edge Coanda jets from the stator vanes
  will be investigated as a means of achieving
  radial variations of the incident flow angles.