Application of casing treatment to an industrial axial-flow fan

1998 ◽  
Vol 212 (4) ◽  
pp. 225-233 ◽  
Author(s):  
S D Hill ◽  
R L Elder ◽  
A B McKenzie
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
Strain Gauges ◽  
Axial Flow Fan ◽  
Fan Noise ◽  
Flow Measurements ◽  
Casing Treatment ◽  
Blade Tip ◽  
Fan Blade ◽  
Insight Into

This paper deals with an experimental investigation into the influence of a vaned recess casing treatment on the performance of an industrial-type axial-flow fan with a hub-tip ratio of 0.4. The treatment has been tested in a variety of configurations relative to the fan, with an emphasis on the amount of fan blade tip exposure to the treatment. Two sets of blading, one of which is of the fully reversible type, have been investigated. Detailed flow measurements have been carried out with a slanted hot wire probe to provide an insight into the operation of the device and into the nature of the rotating stall in the solid casing configuration. Strain gauges have been employed to enable blade stresses to be recorded and an in-duct microphone to enable comparative tests on fan noise has also been used.

Discrete Frequency Noise Generation From an Axial Flow Fan Blade Row

1970 ◽  
Vol 92 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Ramani Mani
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Acoustic Energy ◽  
Frequency Noise ◽  
Noise Generation ◽  
Two Dimensional ◽  
Axial Flow Fan ◽  
Fan Noise ◽  
Blade Row ◽  
Fan Blade

An analysis is presented which treats the noise generation from an axial flow fan row by given forces including the effects of a moving medium. The linearization of Euler’s equations to yield tractable problems for fan noise is discussed. The three-dimensional problem is decomposed into several two-dimensional problems. Finally, full details are given of a two-dimensional analysis to predict the amounts of acoustic energy, at the blade passing frequency and its harmonics, radiated up and downstream of a blade row due to its interaction with a neighboring row.

scholarly journals Recessed Casing Treatment Effects on Fan Performance and Flow Field

1995 ◽  
Author(s):  
C. S. Kang ◽  
A. B. McKenzie ◽  
R. L. Elder
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Pressure Rise ◽  
Operating Efficiency ◽  
Flow Measurements ◽  
Blade Loading ◽  
Stall Margin ◽  
Casing Treatment ◽  
Stall Margin Improvement ◽  
Blade Tip

An experimental investigation to examine the influence of the vaned recess casing treatment on stall margin, operating efficiency and the flow field of a low speed axial flow fan with aerospace type blade loading is presented. Different geometrical designs of the vaned passages were examined. The best configuration resulted in a stall margin improvement of 67%, a significantly higher pressure rise in the stall region and insignificant change in peak efficiency. Detailed 3-D flow measurements in the endwall region and in the casing recess were carried out with a slanted hot-wire, providing some insight to the operation of the device. The results revealed that the stall margin improvement was largely due to the removal of flow from the blade tip to the recess, and the elimination of the growth of the stall region at the tip, which occurs at stall in the solid casing build.

Improvement of Unstable Characteristics of an Axial Flow Fan by Air-Separator Equipment

1987 ◽  
Vol 109 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Y. Miyake ◽  
T. Inaba ◽  
T. Kato
Keyword(s):  
Pressure Distribution ◽  
Axial Flow ◽  
Rotating Stall ◽  
Axial Flow Fan ◽  
Blade Passage ◽  
Geometric Conditions ◽  
Different Types ◽  
Blade Tip ◽  
Discharge Distribution ◽  
Air Separator

The authors’ previous papers demonstrated that an air-separator is the most effective equipment among various different types for the improvement of unstable characteristics of an axial-flow rotor. Further experiments revealed that this equipment could eliminate the unstable characteristics thoroughly even for a build which originally accompanied a heavy rotating stall. This paper describes the geometric conditions to realize this and discusses its performance mechanism on the basis of the experiments showing the discharge distribution of the bleeding flow from the blade tip to separator passage as well as the pressure distribution in a blade passage at the tip section of the rotor. It is suggested that the equipment is equally useful at any stage of a multistage rotor.

Optimization of Stacking Line and Blade Profile for Design of Axial Flow Fan Blade

2008 ◽  
Author(s):  
Abdus Samad ◽  
Ki-Sang Lee ◽  
Kwang-Yong Kim
Keyword(s):  
Objective Function ◽  
Surrogate Model ◽  
Stokes Equations ◽  
Axial Flow ◽  
Weighted Average ◽  
Optimization Procedure ◽  
Total Efficiency ◽  
Blade Profile ◽  
Axial Flow Fan ◽  
Fan Blade

This work presents a numerical optimization procedure for a low-speed axial flow fan blade with weighted average surrogate model. Reynolds-averaged Navier-Stokes equations with SST turbulence model are discretized by finite volume approximations and solved on hexahedral grids for flow analyses. The blade profile as well as stacking line is modified to enhance blade total efficiency, i.e., the objective function. Six design variables related to blade lean and blade profile are selected, and a design of experiments technique produces design points where flow analyses are performed to obtain values of the objective function. PBA model is employed as a surrogate model for optimization. A search algorithm is used to find the optimal design in the design space from the constructed surrogate model for the objective function. As a main result, the efficiency is increased effectively by the present optimization procedure.

scholarly journals Axial Flow Fan Noise Studies

1972 ◽  
Vol 38 (312) ◽  
pp. 2093-2101
Author(s):  
Kang Rae CHO ◽  
Susumu MURATA
Keyword(s):  
Axial Flow ◽  
Axial Flow Fan ◽  
Fan Noise

The Measurement and Interpretation of Flow within Rotating Stall Cells in Axial Compressors

1978 ◽  
Vol 20 (2) ◽  
pp. 101-114 ◽  
Author(s):  
I. J. Day ◽  
N.A. Cumpsty
Keyword(s):  
Flow Direction ◽  
Axial Flow ◽  
Tangential Direction ◽  
Rotating Stall ◽  
Design Flow ◽  
Flow Measurements ◽  
Axial Compressors ◽  
Multi Stage ◽  
Wide Range ◽  
Flow Compressor

Detailed flow measurements obtained by a new measuring technique are presented for the flow in a stalled axial-flow compressor. Results were obtained from a wide range of compressor builds, including multi-stage and single-stage configurations of various design flow rates and degrees of reaction. Instantaneous recordings of absolute velocity, flow direction and total and static pressures have been included for both full-span and part-span stall. With the aid of these results, it has been shown that the conventional model of the flow in a stall cell is erroneous. An alternative model is proposed, based on the observation that the fluid must cross from one side of the cell to the other in order to preserve continuity in the tangential direction. An investigation of the experimental results also reveals the finer details of the flow in the cell and shows how these details are related to the design flow rate of the compressor. The influence of these cell details on the power absorbed by a stalled compressor are investigated, and consideration is given to the complex pressure patterns encountered in the compressor.

scholarly journals Application of Recess Vaned Casing Treatment to Axial Flow Fans

1989 ◽  
Author(s):  
A. R. Azimian ◽  
R. L. Elder ◽  
A. B. McKenzie
Keyword(s):  
Unsteady Flow ◽  
Frequency Response ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Axial Position ◽  
Flow Conditions ◽  
Peak Efficiency ◽  
Stall Margin ◽  
Casing Treatment

The effect of applying a vaned recessed casing treatment to a single stage axial flow fan has been investigated. The influence of the axial position of the recess relative to the rotor leading edge and other geometrical modifications of the vane passage have been examined. Significant improvements in stall margin were observed without (in some builds) loss in peak efficiency. Slow and fast frequency response yawmeter probes have been used in the study to examine both the steady flow conditions and the unsteady flow caused by rotating stall.

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