Axial compressor

About: Axial compressor is a research topic. Over the lifetime, 12035 publications have been published within this topic receiving 127766 citations.

Stability of a pair of co-rotating vortices with axial flow

Abstract: The three-dimensional linear temporal stability properties of a flow composed of two corotating q-vortices (also called Batchelor vortices) are predicted by numerical stability analysis As for the corresponding counter-rotating case, when the axial flow parameter is increased, different instability modes are observed and identified as a combination of resonant Kelvin modes of azimuthal wavenumbers m and m+2 within each vortex In particular, we show that the sinuous mode, which is the dominant instability mode without axial flow, is stabilized in the presence of a moderate axial flow Different types of mode with a large amplitude in the critical layer are also identified For small separation distances (above the merging threshold), unstable eigenmodes, corresponding to axial wavenumbers that cannot be easily identified with simple resonant interactions of Kelvin modes, are also observed Their growth rate is a substantial fraction of the growth rates of low-order resonant modes The effects of the Reynolds number and vortex separation distance on the growth rate parameter map are considered Finally, we analyze the similarities and differences between the stability characteristics of co- and counter-rotating vortex pairs

Periodical Unsteady Flow Within a Rotor Blade Row of an Axial Compressor—Part II: Wake-Tip Clearance Vortex Interaction

Abstract: In this two-part paper results of the periodical unsteady flow field within the third rotor blade row of the four-stage Dresden Low-Speed Research Compressor are presented. The main part of the experimental investigations was performed using Laser-Doppler-Anemometry. Results of the flow field at several spanwise positions between midspan and rotor blade tip will be discussed. In addition time-resolving pressure sensors at midspan of the rotor blades provide information about the unsteady profile pressure distribution. In part II of the paper the flow field in the rotor blade tip region will be discussed. The experimental results reveal a strong periodical interaction of the incoming stator wakes and the rotor blade tip clearance vortices. Consequently, in the rotor frame of reference the tip clearance vortices are periodical with the stator blade passing frequency. Due to the wakes the tip clearance vortices are separated into different segments. Along the mean vortex trajectory these parts can be characterised by alternating patches of higher and lower velocity and flow turning or subsequent counterrotating vortex pairs. These flow patterns move downstream along the tip clearance vortex path in time. As a result of the wake influence the orientation and extension of the tip clearance vortices as well as the flow blockage periodically vary in time.Copyright © 2007 by ASME

Spiral-based axial flow devices

Abstract: Axial flow devices using rigid spiral band profiled blade catenaries attached variably along and around an axially elongated profiled hub, of axially oriented profile section sequences 75 mapped relative to truncated cones-of-generation. Upon rotation and lubricity-masked progression through axial planes-of-shear, this time-domain sequence travels in 2-dimensional axial-datum-plane-relative path-excursions and ejects frictional adhesions via anguillar reverse vortex street thrust due to an after-body accelerating wave shape-sequence 48 . This guides bound vortex pressures at linear path-velocity substantially parallel to the collective plane-of-shear, conferring higher differential pressures through path-vector-addition, improved force-vector orientation, extended laminar flows, lower form drag and tip vorticity. As a wind turbine, path-vectors are added to inflow, ducting an increased mass flow inward for increased power extraction per diameter. As a propeller, path-vector-subtraction guides the wave front flight-path-transverse, allowing higher flight velocities and improving thrust-per-torque through enhanced force vectors and mass flow rates.

Method and system for controlling variable compressor geometry

Abstract: A method and system for controlling the position of a variable pitch vane stage (34) in a gas turbine engine (10) uses a feedback loop comparing the current compressor pressure ratio to a reference compressor pressure ratio. The reference pressure ratio is determined from a plurality of current engine operating parameters which identify a unique point on the compressor operating line.