Axial compressor

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

Axial-flow fan

Abstract: An axial flow fan includes a plurality of auxiliary blades disposed upon and projecting from the suction and/or pressure surfaces of primary fan blades radially disposed on a hub member The auxiliary blades extend substantially in the width direction or transversely of the primary blades, and the leading edges of the auxiliary blades, as viewed in the rotational axis direction of the fan, are disposed closer to the rotational center of the hub member than the trailing edges of the auxiliary blades In this manner, the axial flow fan produces an axial fluid flow by means of the primary blades and a radial fluid flow by means of the auxiliary blades

Effect of tip clearance on stall evolution process in a low-speed axial compressor stage

Abstract: Effect of the tip clearance on the transient process of rotating stall evolution has been studied experimentally in a low-speed axial compressor stage with various stator-rotor gaps. In the previous authors’ experiments for the small tip clearance, the stall evolution process of the rotor was sensitive to the gaps between the blade rows. For the large tip clearance, however, little difference is observed in the evolution processes independently of the blade row gap. In the first half process, it is characterized by gradual reduction of overall pressure-rise with flow rate decreasing, and the number of short length-scale disturbances is increasing with their amplitude increasing. In the latter half a long length-scale disturbance develops rapidly to result in deep stall. Just before the stall inception the spectral power density of the casing wall pressure reveals the existence of rotating disturbances with broadband high frequency near a quarter of the blade passing frequency. This is caused by the short length-scale disturbances occurring intermittently. A flow model is presented to explain mechanisms of the rotating short length-scale disturbance, which includes a tornado-like separation vortex and tip-leakage vortex breakdown. The model is supported by a result of a numerical unsteady flow simulation.Copyright © 2004 by ASME

Experimental and Computational Analysis of a Multistage Axial Compressor Including Stall Prediction by Steady and Transient CFD Methods

Abstract: Siemens Energy has commissioned an extensive multi-year experimental and numerical (CFD) project to improve its ability to design for and predict compressor stall. The experimental test rig is a half scale six stage axial compressor. The goal of this work is to provide insight into how best to predict the compressor performance map and in particular the stall point by applying state-of-the-art multiple blade row CFD simulation tools. A preliminary CFD analysis quantified numerical, model and systematic error on the first stage of the compressor. Subsequent steady (Mixing Plane) and transient (Time Transformation) CFD simulations of the entire six stage compressor are compared to each other and to experimental data. Both the steady and transient simulations are shown to be computationally efficient and in very good agreement with the experimental data across the full performance map, up to stall inception on multiple speedlines. Physical explanations of the key flow features observed in the experiment, as well as of the differences between the predictions and experimental data, are given.Copyright © 2013 by Siemens Energy, Inc.

Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines-Part II: Effect of Relative Casing Motion

Abstract: A numerical study has been performed to investigate the effect of casing motion on the lip leakage flow and heat transfer characteristics in unshrouded axial flow turbines. The relative motion between the blade tip and the casing was simulated by moving the casing in a direction from the suction side to the pressure side of the stationary blade. Base line flat tip geometry and squealer type geometries, namely, double squealer or cavity and suction side squealer, were considered at a clearance gap of 1.6%C. The computations were performed using a single blade with periodic boundary conditions imposed along the boundaries in the pitchwise direction. Turbulence was modeled using the shear stress transport k-omega model. The flow conditions correspond to an exit Reynolds number of 2.3 x 10(5). The results were compared to those obtained without the relative casing motion reported in Part I of this paper. In general, the effect of relative casing motion was to decrease the tip leakage mass flow and the average heat transfer to the tip due to the decrease in leakage flow velocity caused by a drop in driving pressure difference. Compared to the computations with stationary casing, in the case of all the three geometries considered, the average heat transfer to the suction surface of the blade was found to be larger in the case of the computations with relative casing motion. At a larger clearance gap of 2.8%C, in case of a flat tip, while the tip leakage mass flow decreased due to relative casing motion, only a smaller change in the average heat transfer to the tip and the suction surface of the blade was noticed.