Axial compressor

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

Gas turbine compression system and compressor structure

Abstract: The invention relates to a gas turbine compression system (1) comprising a gas channel (5), a low pressure compressor section (8) and a high pressure compressor section (9) for compression of the gas in the channel and a compressor structure (14) arranged between the low pressure compressor section (8) and the high pressure compressor section (9). The compressor structure (14) being designed to conduct a gas flow in the gas channel and comprises a plurality of radial struts (15, 16, 21, 24, 25) for transmission of load, wherein at least one of said struts (15, 16, 21, 24, 25) is hollow for housing service components. The compressor structure (14) is arranged directly downstream a last rotor (10) in the low pressure compressor section (8) and designed for substantially turning a swirling gas flow from said rotor (10) by a plurality of said struts (15, 16, 21, 24, 25) having a cambered shape.

Methods and systems for surge control

Abstract: Methods and systems are provided for recirculating compressed air across a compressor through a high flow and a low flow compressor recirculation path. Flow through the recirculation paths is controlled via respective valves and valve opening is adjusted based on a throttle mass flow so as to maintain a compressor flow rate at or above a surge constrained flow rate. By maintaining a sufficiently high compressor flow rate during steady state and transient conditions, the compressor state can be maintained outside a surge region.

Characteristics of Tip Clearance Flow Instability in a Transonic Compressor

Abstract: In the present study, unsteady flow phenomena due to tip clearance flow instability in a modern transonic axial compressor rotor are studied in detail. First, unsteady flow characteristics due the oscillating tip clearance vortex measured with the particle image velocimetry (PIV) and casing-mounted unsteady pressure transducers are analyzed and compared to numerical results with a large eddy simulation (LES). Then, measured characteristic frequencies of the unsteady flow near stall operation are investigated. The overall purpose of the study is to advance the current understanding of the unsteady flow field near the blade tip in an axial transonic compressor rotor near the stall operating condition. Flow interaction between the tip leakage vortex and the passage shock is inherently unsteady in a transonic compressor. The currently applied PIV measurements indicate that the flow near the tip region is unsteady even at the design condition. This self-induced unsteadiness increases significantly as the compressor operates toward the stall condition. PIV data show that the tip clearance vortex oscillates substantially near stall. The calculated unsteady characteristics from LES agree well with the PIV measurements. Calculated unsteady flow fields show that the formation of the tip clearance vortex is intermittent and the concept of vortex breakdown from steady flow analysis does not seem to apply in the current flow field. Fluid with low momentum near the pressure side of the blade close to the leading edge periodically spills over into the adjacent blade passage. The spectral analysis of measured end wall and blade surface pressure shows that there are two dominant frequencies near stall. One frequency is about 40-60% of the rotor rotation and the other dominant frequency is about 40-60% of the blade passing frequency (BPF). The first frequency represents the movement of a large blockage over several consecutive blade passages against the rotor rotation. The second frequency represents traditional tip flow instability, which has been widely observed in subsonic compressors. The LES simulations show that the second frequency is due to movement of the instability vortex.

Rotating Stall Suppression in Axial Compressors with Casing Plasma Actuation

Abstract: optimumactuatorlocationandrequiredactuationstrengthtoachievethedesiredeffectsatlowandmediumsubsonic compressor speeds. Results show that plasma actuation near the rotor leading edge and concentrated in the tip clearancegapregionmosteffectivelysuppressesbothofthecriteriaforspikestallinceptionanddelaysthepredicted stall point to a lower flow coefficient with relatively low power input. In addition, the observed increase in rotor pressure-rise characteristic from the proposed actuation means that the concept, with a new suggested actuator modification,canalsobeusedtosuppressmodalstallinception.Thesimulationsindicatethatactuationeffectiveness decreaseswithincreasingrotortipspeed,thattherequiredactuatorstrengthscaleswiththisspeed,andthatstronger actuation strength than that of conventional single dielectric barrier discharge plasma actuators may be needed. Some implications for the practical implementation of this concept on real compressors are also discussed.