This paper describes a new three-dimensional theory to calculate the efficiency or loss of nozzle guide vane annular cascades from experimental area traverse measurements of the compressible downstream flow. To calculate such an efficiency, it is necessary to mix out the measured flow computationally to either a uniform state or one that is a function of radius only. When this is done by conserving momentum, mass, and energy flow, there is a remaining degree of freedom in that the radial distribution of circumferential velocity can be chosen. This extra freedom does not arise in two-dimensional cascades. The new method mixes the flow out to a free (i.e., irrotational) vortex. This is preferred to existing methods in that it gives a physically realistic flow and also provides a unique, lossless, isentropic reference flow. The annular cascade efficiency is then uniquely defined as the ratio of the mixed-out experimental kinetic energy flux to the ideal isentropic kinetic energy flux at the same mean radius static pressure. The mathematical derivation of this method is presented. This new theory has been used to process data obtained from a large, transonic, annular cascade in a blowdown tunnel. A four-hole pyramid probe, mounted on a computer-controlled traverse, has been used to map the passage flowfield downstream of the nozzle guide vanes. Losses calculated by the new method are compared with those calculated from the same data using earlier analysis methods.
Skip Nav Destination
Article navigation
April 1997
Research Papers
Free Vortex Theory for Efficiency Calculations From Annular Cascade Data
A. J. Main,
A. J. Main
Department of Engineering Science, Oxford University, Oxford, United Kingdom
Search for other works by this author on:
M. L. G. Oldfield,
M. L. G. Oldfield
Department of Engineering Science, Oxford University, Oxford, United Kingdom
Search for other works by this author on:
G. D. Lock,
G. D. Lock
Department of Engineering Science, Oxford University, Oxford, United Kingdom
Search for other works by this author on:
T. V. Jones
T. V. Jones
Department of Engineering Science, Oxford University, Oxford, United Kingdom
Search for other works by this author on:
A. J. Main
Department of Engineering Science, Oxford University, Oxford, United Kingdom
M. L. G. Oldfield
Department of Engineering Science, Oxford University, Oxford, United Kingdom
G. D. Lock
Department of Engineering Science, Oxford University, Oxford, United Kingdom
T. V. Jones
Department of Engineering Science, Oxford University, Oxford, United Kingdom
J. Turbomach. Apr 1997, 119(2): 247-255 (9 pages)
Published Online: April 1, 1997
Article history
Received:
February 22, 1995
Online:
January 29, 2008
Citation
Main, A. J., Oldfield, M. L. G., Lock, G. D., and Jones, T. V. (April 1, 1997). "Free Vortex Theory for Efficiency Calculations From Annular Cascade Data." ASME. J. Turbomach. April 1997; 119(2): 247–255. https://doi.org/10.1115/1.2841107
Download citation file:
Get Email Alerts
Cited By
A Digital Engineering Analysis of an Additively-Manufactured Turbine Vane
J. Turbomach (May 2025)
Mode Analysis for the Rotating Aerodynamic Disturbance of a Transonic Fan
J. Turbomach (May 2025)
Effect of Ceramic Matrix Composites on the Thermal Efficiency of a Power Generation Turbine
J. Turbomach (May 2025)
Heat Transfer Enhancement in Pulsating Flows: A Bayesian Approach to Experimental Correlations
J. Turbomach (May 2025)
Related Articles
Effect of Freestream Velocity on the Three-Dimensional Separated Flow Region in Front of a Cylinder
J. Fluids Eng (March,1991)
The Influence of Endwall Contouring on the Performance of a Turbine Nozzle Guide Vane
J. Turbomach (April,1999)
The Influence of Leading-Edge Geometry on Secondary Losses in a Turbine Cascade at the Design Incidence
J. Turbomach (April,2004)
Related Proceedings Papers
Related Chapters
Experimental Investigation of Ventilated Supercavitation Under Unsteady Conditions
Proceedings of the 10th International Symposium on Cavitation (CAV2018)
Antilock-Braking System Using Fuzzy Logic
International Conference on Mechanical and Electrical Technology, 3rd, (ICMET-China 2011), Volumes 1–3
Cardiac Murmur Classification Based on Analysis of the Phonocardiogram to Estimate the Number of Degrees of Freedom of the Heart Modelled as a Nonlinear System
Intelligent Engineering Systems through Artificial Neural Networks, Volume 16