Axial compressor

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

Intercooled gas turbine engine with integral air bottoming cycle

Abstract: A gas turbine engine that includes a 2/3 stage intercooled booster compressor is described. In one embodiment, the engine includes a low pressure turbine and a booster compressor rotatable on a low pressure shaft. The engine further includes a high pressure compressor, a high pressure combustor, and a high pressure turbine rotatable on a high pressure (HP) shaft and forming the core engine. A low pressure combustor is located at the outlet of the high pressure turbine and a power turbine. The booster compressor includes first and second stage compressors, and air flow from the first stage compressor is supplied to a first intercooler, and air flow from the second stage compressor is supplied to a second intercooler. Airflow from the first intercooler is supplied to the inlet of the second stage compressor, and airflow from the second intercooler is split between being provided to the inlet of the high pressure compressor and a recuperator. The recuperator also is coupled to receive air from the power turbine so that air from the power turbine heats air split away from the second stage compressor before being exhausted to atmosphere. Air heated in the recuperator drives the low pressure turbine connected to the booster compressors.

Theory of Compressor Stability Enhancement Using Novel Casing Treatment, Part II: Experiment

Abstract: A stall precursor-suppressed casing treatment is designed to enhance stall margin for both subsonic and transonic compressors. It is noted that the open area ratio of the stall precursor-suppressed casing treatment is only 4–10%, far smaller than conventional casing treatments, with over 50% open area ratio. The effect of the novel casing treatment on the stall margin and efficiency of compressors has been investigated experimentally. The results show that the stall precursor-suppressed casing treatment can improve the stall margin by about 8–18% without significantly decreasing the efficiency of the related fan/compressors. Meanwhile, the present investigation has also attempted to reveal the mechanism of stall margin improvement with such casing treatment. It is found that the stall precursor-suppressed casing treatment will delay the nonlinear development of the stall process by suppressing the propagation of the stall precursor waves, as compared with the evolution of the precursors without casing tre...

Centerline velocity decay of a circular jet in a counterflowing stream

Abstract: We use an advection hypothesis to analyze the decay of centerline velocity of a circular jet issuing into a counterflowing stream. Working in the Lagrangian frame, we follow the locations and velocity gradients of jet fluid particles along the jet central axis while the particles are being advected backwards by the counterflow. The spatial velocity gradient along the jet centerline is thus obtained and subsequently integrated to describe the spatial decay of axial velocities. Laser-doppler velocity measurements are performed in the laboratory and the data are well predicted by our analytical expression of centerline velocity decay. Looking from another view, our treatment supports that the effect of an external axial flow stream on the jet flow field can be represented by a certain degree of stretching or contracting of the jet in the axial direction.

Aerodynamic Instability and Life-Limiting Effects of Inlet and Interstage Water Injection Into Gas Turbines

Abstract: Gas turbine power enhancement technologies, such as inlet fogging, interstage water injection, saturation cooling, inlet chillers, and combustor injection, are being employed by end users without evaluating the potentially negative effects these devices may have on the operational integrity of the gas turbine. Particularly, the effect of these add-on devices, off-design operating conditions, nonstandard fuels, and compressor degradation/ fouling on the gas turbine's axial compressor surge margin and aerodynamic stability is often overlooked. Nonetheless, compressor aerodynamic instabilities caused by these factors can be directly linked to blade high-cycle fatigue and subsequent catastrophic gas turbine failure; i.e., a careful analysis should always proceed the application of power enhancement devices, especially if the gas turbine is operated at extreme conditions, uses older internal parts that are degraded and weakened, or uses nonstandard fuels. This paper discusses a simplified method to evaluate the principal factors that affect the aerodynamic stability of a single-shaft gas turbine's axial compressor. As an example, the method is applied to a frame-type gas turbine and results are presented. These results show that inlet cooling alone will not cause gas turbine aerodynamic instabilities, but that it can be a contributing factor if for other reasons the machine s surge margin is already slim. The approach described herein can be employed to identify high-risk applications and bound the gas turbine operating regions to limit the risk of blade life reducing aerodynamic instability and potential catastrophic failure.