Detailed heat transfer measurements in nozzle guide vane passages in linear and annular cascades in the presence of secondary flows

Two transient techniques are used to measure the heat transfer coefficient distributions in nozzle guide vane passages. The first employs liquid crystal methods in a Cold Heat Transfer Tunnel and examines the flow in a two-dimensional cascade. The second uses localized thin film heat transfer gauges within an annular cascade at engine representative Mach numbers and Reynolds numbers. The techniques are described and the resulting heat transfer coefficient distributions are discussed and interpreted in terms of the secondary flows and vortex structures. Typical heat transfer distributions are presented over the endwalls and blade surfaces. An analysis of the endwall heat transfer results is presented for the annular cascade.