Wake, Shock, and Potential Field Interactions in a 1.5 Stage Turbine—Part I: Vane-Rotor and Rotor-Vane Interaction

The composition of the time-resolved surface pressure field around a high-pressure rotor blade caused by the presence of neighboring blade rows is investigated, with the individual effects of wake, shock and potential field interaction being determined. Two test geometries are considered: first, a high-pressure turbine stage coupled with a swan-necked diffuser exit duct; secondly, the same high-pressure stage but with a vane located in the downstream duct. Both tests were conducted at engine-representative Mach and Reynolds numbers, and experimental data was acquired using fast-response pressure transducers mounted on the mid-height streamline of the HP rotor blades. The results are compared to time-resolved computational predictions of the flowfield in order to aid interpretation of experimental results and to determine the accuracy with which the computation predicts blade interaction. The paper is split into two parts: the first investigating the effect of the upstream vane on the unsteady pressure field around the rotor (vane-rotor interaction), and the second investigating the effect of the downstream vane on the unsteady pressure field around the rotor (rotor-vane interaction). The paper shows that at typical design operating conditions shock interaction from the upstream blade row is an order of magnitude greater than wake interaction and that with the design vane-rotor inter-blade gap the presence of the rotor causes a periodic increase in the strength of the vane trailing edge shock. The presence of the potential field of the downstream vane is found to affect significantly the rotor pressure field downstream of the Mach one surface within each rotor passage.

[1]  U. K. Singh,et al.  UNSTEADY FLOW IN A SINGLE STAGE TURBINE , 1998 .

[2]  Michael B. Giles,et al.  Stator/rotor interaction in a transonic turbine , 1988 .

[3]  H. Hodson,et al.  On the Interpretation of Measured Profile Losses in Unsteady Wake-Turbine Blade Interaction Studies , 1996 .

[4]  Reza S. Abhari,et al.  Influence of Vane-Blade Spacing on Transonic Turbine Stage Aerodynamics: Part II—Time-Resolved Data and Analysis , 1999 .

[5]  Theodosios Korakianitis,et al.  On the Propagation of Viscous Wakes and Potential Flow in Axial-Turbine Cascades , 1991 .

[6]  A. J. Dietz,et al.  Unsteady Pressure Measurements on the Rotor of a Model Turbine Stage in a Transient Flow Facility , 1992 .

[7]  Anthony G. Sheard,et al.  A Transient Flow Facility for the Study of the Thermofluid-Dynamics of a Full Stage Turbine Under Engine Representative Conditions , 1988 .

[8]  Roger W. Ainsworth,et al.  The unsteady pressure field over a turbine blade surface: visualisation and interpretation of experimental data , 1997 .

[9]  Guillermo Paniagua,et al.  Investigation of the Unsteady Rotor Aerodynamics in a Transonic Turbine Stage , 2000 .

[10]  Michael G. Dunn,et al.  Investigation of unsteady flow through a transonic turbine stage : data/prediction comparison for time-averaged and phase-resolved pressure data , 1992 .

[11]  H. Kruse,et al.  An Experimental Investigation Into the Effect of Wakes on the Unsteady Turbine Rotor Flow , 1985 .

[12]  J. D. Denton,et al.  The Calculation of Three Dimensional Viscous Flow Through Multistage Turbomachines , 1990 .

[13]  A. Binder,et al.  Turbulence Production Due to Secondary Vortex Cutting in a Turbine Rotor , 1985 .

[14]  H. Hodson.  Measurements of wake-generated unsteadiness in the rotor passages of axial flow turbines , 1985 .

[15]  Denis J. Doorly,et al.  Simulation of the Effects of Shock Wave Passing on a Turbine Rotor Blade , 1985 .

[16]  Roger W. Ainsworth,et al.  Time-resolved vane-rotor-vane interaction in a transonic one-and-a-half stage turbine , 2001 .

[17]  M. D. Lefcort,et al.  An Investigation Into Unsteady Blade Forces in Turbomachines , 1965 .

[18]  Neil William Harvey,et al.  Wake, Shock, and Potential Field Interactions in a 1.5 Stage Turbine—Part II: Vane-Vane Interaction and Discussion of Results , 2003 .