Redesign and Performance Analysis of a Transonic Axial Compressor Stator and Equivalent Plane Cascades With Subsonic Controlled Diffusion Blades

Abstract

In order to verify a new controlled diffusion blade design concept, the stator of an existing transonic axial compressor stage was redesigned. Stator and equivalent cascade tests revealed the potential of such blades for a considerably higher aerodynamic loading than it has been applied up to now. The design procedure is described, and the results of plane cascade and stage testing are submitted, including performance analysis of both cascade and stator blade sections, at design and off-design operating conditions. The blade profile shapes and cascade geometries were calculated by means of an inverse, two-dimensional method taking also into account the axial velocity density ratio (AVDR). This design concept is essentially based on prescribed blade pressure distributions, which are optimized with respect to the blade boundary layer development. The flow phenomena are illustrated by means of loss and flow turning investigations, blade pressure distributions, and laser velocimetry data. The test results reveal that the two-dimensional approach applied is quite promising for the three-dimensional blade design. Finally, overall and blade element performance comparisons between the original NACA 65 profiled stator and the redesigned one demonstrate the favorable flow behavior of the new stator, as well as the great potential of the controlled diffusion blade concept.

Theoretical Model of the Spanwise Mixing Caused by Periodic Incoming Wakes

“…However, it is unlikely that the neglect of this effect causes a serious error in estimating their magnitudes for compressor flows where the loading is relatively light even if it is of modem compressors. Actually, the experimental results of turbulent intensity inside a modem transonic compressor using L2F anemometry by Dunker et al (1984) revealed that the chopped rotor wakes took a nearly constant wake width in the circumferential direction inside the subsequent stator flows. Therefore our assumption may be generally proper for compressor flows, though it is not expected to be true for turbine flows where the loading is much heavier than compressors so that the chopped wakes inside turbines should be described by a more complex function of the axial and circumferential coordinates, as demonstrated by Hodson (1984) in his unsteady CFD calculation .…”

Application of an Inverse Design Procedure to Axial Compressor Blading

“…They (Hobbs, Weingold) designated it as a Controlled Diffusion Airfoil (CDA). Dunker et al [7] used the control diffusion concept to redesign a subsonic stator. The design procedure, however, was based on a potential flow calculation and did not include the effect of streamtube thickness and radius variation.…”

A progressive optimization for the inverse design of blade profile based on sequential quadratic programming

“…In the development of blade design methods, inverse methods have been developed to replace traditional methods [1][2][3][4]. The potential-stream function analytic method is very powerful for engineering applications among those methods [5][6][7]. A geometric equation of coordinates of the profile shape (Fig.…”