Turbulence Scale Effects on Heat Transfer in a Linear Turbine Cascade
Abstract
Heat transfer for a turbine cascade is examined for turbulence scale effects. The turbulence integral scale and microscale lengths of the free-stream flow are controlled by air-jet injection through a grid placed in the free- stream flow. Air is injected into the flow in three primary directions: co-flow, cross-flow, and counter-flow, at several injection pressures. Results are obtained for heat transfer on the blade without the jet-grid in the free-stream flow. Surface pressures on the turbine blade are examined for three injection directions. Surface heat transfer on the blade and turbulence intensity and turbulence scale results are obtained for two grid locations, three air injection orientations, and three injection orifice diameters over a range of injection pressures. Turbulence integral scale and microscale lengths are measured in two free-stream flow coordinates. Results show the integral scale length is primarily dependent on the diameter of the jet-grid tube, but may be controlled to a lesser degree by changing the orientation of the jet-grid injection to a co-flow or counter-flow direction; or by changing the secondary air-jet injection pressure. The turbulence microscale is primarily dependent on the location of the jet-grid within the flow, but, to a lesser degree, controlled by the orientation of the jet-grid injection, jet orifice diameter, and injection pressure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA216222
Entities
People
- Lello Galassi
Organizations
- Air Force Institute of Technology