scholarly journals Efficient Laser Anemometer for Intra-Rotor Flow Mapping in Turbomachinery

1981 ◽  
Vol 103 (2) ◽  
pp. 424-429 ◽  
Author(s):  
J. A. Powell ◽  
A. J. Strazisar ◽  
R. G. Seasholtz
Keyword(s):  
Axial Flow ◽  
Flow Mapping ◽  
Graphic Display ◽  
Flow Measurements ◽  
Compressor Rotor ◽  
Seed Particles ◽  
Laser Anemometer ◽  
Efficient Data ◽  
Flow Compressor ◽  
Data Acquisition Process

Innovative features of the anemometer include: (1) a rapid and efficient data acquisition process, (2) a detailed real-time graphic display of the data being accumulated, and (3) input laser beam positioning that maximizes the size of the intra-rotor region being mapped. Results are presented that demonstrate the anemometer’s capability in flow mapping within a transonic axial-flow compressor rotor. Typically, a velocity profile, derived from 30,000 measurements along 1000 sequential circumferential positions covering 20 blade passages, can be obtained in 30 s. The use of fluorescent seed particles allows flow measurements near the rotor hub and the casing window.

scholarly journals Laser Anemometer Measurements in a Transonic Axial Flow Compressor Rotor

1981 ◽  
Vol 103 (2) ◽  
pp. 430-437 ◽  
Author(s):  
A. J. Strazisar ◽  
J. A. Powell
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Compressor Rotor ◽  
Laser Anemometer ◽  
Flow Phenomena ◽  
Conventional Instrumentation ◽  
Efficient Data ◽  
Shock System ◽  
Flow Compressor ◽  
Anemometer System

A laser anemometer system employing an efficient data acquisition technique has been used to make measurements upstream, within, and downstream of the compressor rotor. A fluorescent dye technique allowed measurements within endwall boundary layers. Adjustable laser beam orientation minimized shadowed regions and enabled radial velocity measurements outside of the blade row. The flow phenomena investigated include flow variations from passage to passage, the rotor shock system, three-dimensional flows in the blade wake, and the development of the outer endwall boundary layer. Laser anemometer measurements are compared to a numerical solution of the streamfunction equations and to measurements made with conventional instrumentation.

scholarly journals Effect of Circumferential Single Casing Groove Location on the Flow Stability under Tip-Clearance Effect in a Transonic Axial Flow Compressor Rotor

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6143
Author(s):  
Xiaoxiong Wu ◽  
Bo Liu ◽  
Botao Zhang ◽  
Xiaochen Mao
Keyword(s):  
Control Mechanism ◽  
Incidence Angle ◽  
Axial Flow ◽  
Flow Stability ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Flow Angle ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

Numerical simulations have been performed to study the effect of the circumferential single-grooved casing treatment (CT) at multiple locations on the tip-flow stability and the corresponding control mechanism at three tip-clearance-size (TCS) schemes in a transonic axial flow compressor rotor. The results show that the CT is more efficient when its groove is located from 10% to 40% tip axial chord, and G2 (located at near 20% tip axial chord) is the best CT scheme in terms of stall-margin improvement for the three TCS schemes. For effective CTs, the tip-leakage-flow (TLF) intensity, entropy generation and tip-flow blockage are reduced, which makes the interface between TLF and mainstream move downstream. A quantitative analysis of the relative inlet flow angle indicates that the reduction of flow incidence angle is not necessary to improve the flow stability for this transonic rotor. The control mechanism may be different for different TCS schemes due to the distinction of the stall inception process. For a better application of CT, the blade tip profile should be further modified by using an optimization method to adjust the shock position and strength during the design of a more efficient CT.

The Stability-Limiting Flow Mechanisms in a Subsonic Axial-Flow Compressor and Its Passive Control With Casing Treatment

2008 ◽  
Author(s):  
Xingen Lu ◽  
Junqiang Zhu ◽  
Chaoqun Nie ◽  
Weiguang Huang
Keyword(s):  
Flow Instability ◽  
State Of The Art ◽  
Axial Flow ◽  
Flow Mechanism ◽  
Blade Passage ◽  
Casing Treatment ◽  
Compressor Rotor ◽  
Flow Compressor ◽  
The Stability ◽  
End Wall

The phenomenon of flow instability in the compression system such as fan and compressor has been a long-standing “bottle-neck” problem for gas turbines/aircraft engines. With a vision of providing a state-of-the-art understanding of the flow field in axial-flow compressor in the perspective of enhancing their stability using passive means. Two topics are covered in this paper. The first topic is the stability-limiting flow mechanism close to stall, which is the basic knowledge needed to manipulate end-wall flow behavior for the stability improvement. The physical process occurring when approaching stall and the role of complex tip flow mechanism on flow instability in current high subsonic axial compressor rotor has been assessed using single blade passage computations. The second topic is flow instability manipulation with casing treatment. In order to advance the understanding of the fundamental mechanisms of casing treatment and determine the change in the flow field by which casing treatment improve compressor stability, systematic studies of the coupled flow through a subsonic compressor rotor and various end-wall treatments were carried out using a state-of-the-art multi-block flow solver. The numerically obtained flow fields were interrogated to identify complicated flow phenomenon around and within the end-wall treatments and describe the interaction between the rotor tip flow and end-wall treatments. Detailed analyses of the flow visualization at the rotor tip have exposed the different tip flow topologies between the cases with treatment casing and with untreated smooth wall. It was found that the primary stall margin enhancement afforded by end-wall treatments is a result of the tip flow manipulation. Compared to the smooth wall case, the treated casing significantly dampen or absorb the blockage near the upstream part of the blade passage caused by the upstream movement of tip clearance flow and weakens the roll-up of the core vortex. These mechanisms prevent an early spillage of low momentum fluid into the adjacent blade passage and delay the onset of flow instability.

scholarly journals 3D Flow Field Measurement Around a Rotating Stall Cell

1998 ◽  
Author(s):  
C. Palomba ◽  
P. Puddu ◽  
F. Nurzia
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Field Pattern ◽  
Mean Flow ◽  
Axial Section ◽  
Average Technique ◽  
Compressor Rotor ◽  
Flow Compressor

Rotating stall is an unsteady phenomenon that arises in axial and radial flow compressors. Under certain operating conditions a more or less regular cell of turbulent flow develops and propagates around the annulus at a speed lower than rotor speed. Recently little work has been devoted to the understanding of the flow field pattern inside a rotating cell. However, this knowledge could be of help in the understanding of the interaction between the cell and the surrounding flow. Such information could be extremely important during the modelling process when some hypothesis have to be made about the cell behaviour. A detailed experimental investigation has been conducted during one cell operation of an isolated low-speed axial flow compressor rotor using a slanted hot wire and an ensemble average technique based on the cell revolution time. The three flow field components have been measured on 9 axial section for 800 circumferential points and on 21 radial stations to give a complete description of the flow field upstream and downstream of the rotor. Interpretation of data can give a description of the mean flow field patterns inside and around the rotating cell.

Aerodynamics of Compressor Casing Treatment: Part I—Experiment and Time-Accurate Numerical Simulation

2008 ◽  
Author(s):  
Fan Lin ◽  
Fangfei Ning ◽  
Huoxing Liu
Keyword(s):  
Axial Flow ◽  
Peak Efficiency ◽  
Flow Rates ◽  
Casing Treatment ◽  
Compressor Rotor ◽  
Rotor Design ◽  
Mass Flow Rates ◽  
Unsteady Rans ◽  
Flow Compressor ◽  
Operating Points

This paper presents both experimental and unsteady RANS investigations of a slot-type casing treatment at a transonic axial flow compressor rotor. Experimental results show that at 60% and 98% of rotor design wheel speeds, approximately 100% and 200% extra extensions of the rotor operation ranges are achieved, respectively. On the other hand, there are about 3.6% and 2.0% drops of efficiencies at 60% and 98% speeds respectively if comparisons are made at the same peak-efficiency mass flow rates of the solid casing case. If comparing the respective peak efficiencies for the solid casing case with those for the treated casing case, there are still about 3.4% and 0.7% drops at 60% and 98% speeds, respectively. As for the unsteady RANS study, an in-house unsteady RANS code has been used to study the casing treatment flow at several operating points, i.e., the peak efficiency and the near stall with regard to the solid casing case at 60% speed and 98% speed, respectively. It is shown that the interactions between the blade passage flow and the casing treatment flow exhibit different manner at two rotating speeds. The flow condition in which the rotor operates, i.e., either the subsonic condition at the 60% speed or the transonic condition with passage shock presented at the 98% speed, is one of the determinate factors that are responsible for the manner the casing treatment works. The loss production due to casing treatment is also particularly discussed.

A New Approach to the Experimental Study of Turbomachinery Flow Phenomena

1977 ◽  
Vol 99 (1) ◽  
pp. 97-105 ◽  
Author(s):  
J. P. Gostelow
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Axial Flow ◽  
Centrifugal Pumps ◽  
New Approach ◽  
Static Pressure Distribution ◽  
Compressor Rotor ◽  
Flow Phenomena ◽  
On Line ◽  
Flow Compressor

Measurements of the unsteady flow field over a rotor and within its wake are needed in the development of most turbomachines. The technique advocated is that of data acquisition by on-line computer, using the periodic passing of a blade as a phase reference. The phase-lock averaging process is described as is its use in reducing the noise of raw data traces. Measurements of the unsteady flow over a cascade and of the resulting boundary layer behavior are presented. The approach was used in interpreting the unsteady flow field of an axial-flow compressor rotor and the static pressure distribution over the rotor tip. Finally the application to centrifugal pumps is discussed, enabling the designer to obtain information on the suction pressures and the extent of any separated region.

Numerical Investigations of the Coupled Flow Through a Subsonic Compressor Rotor and Axial Skewed Slot

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Xingen Lu ◽  
Wuli Chu ◽  
Junqiang Zhu ◽  
Yangfeng Zhang
Keyword(s):  
Axial Flow ◽  
Tip Clearance ◽  
Stall Margin ◽  
Tip Clearance Flow ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Flow Through ◽  
Flow Compressor

In order to advance the understanding of the fundamental mechanisms of axial skewed slot casing treatment and their effects on the subsonic axial-flow compressor flow field, the coupled unsteady flow through a subsonic compressor rotor and the axial skewed slot was simulated with a state-of-the-art multiblock flow solver. The computational results were first compared with available measured data, that showed the numerical procedure calculates the overall effect of the axial skewed slot correctly. Then, the numerically obtained flow fields were interrogated to identify the physical mechanism responsible for improvement in stall margin of a modern subsonic axial-flow compressor rotor due to the discrete skewed slots. It was found that the axial skewed slot casing treatment can increase the stall margin of subsonic compressor by repositioning of the tip clearance flow trajectory further toward the trailing of the blade passage and retarding the movement of the incoming∕tip clearance flow interface toward the rotor leading edge plane.

Behavior of Tip Leakage Flow in an Axial Flow Compressor Rotor

2006 ◽  
Author(s):  
Yanhui Wu ◽  
Wuli Chu ◽  
Xingen Lu ◽  
Junqiang Zhu
Keyword(s):  
Boundary Layer ◽  
Vortex Breakdown ◽  
Axial Flow ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Pressure Side ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Flow Compressor

The current paper reports on investigations with an aim to advance the understanding of the flow field near the casing of a small-scale high-speed axial flow compressor rotor. Steady three dimensional viscous flow calculations are applied to obtain flow fields at various operating conditions. To demonstrate the validity of the computation, the numerical results are first compared with available measured data. Then, the numerically obtained flow fields are analyzed to identify the behavior of tip leakage flow, and the mechanism of blockage generation arising from flow interactions between the tip clearance flow, the blade/casing wall boundary layers, and non-uniform main flow. The current investigation indicates that the “breakdown” of the tip leakage vortex occurs inside the rotor passage at the near stall condition. The vortex “breakdown” results in the low-energy fluid accumulating on the casing wall spreads out remarkably, which causes a sudden growth of the casing wall boundary layer having a large blockage effect. A low-velocity region develops along the tip clearance vortex at the near stall condition due to the vortex “breakdown”. As the mass flow rate is further decreased, this area builds up rapidly and moves upstream. This area prevents incoming flow from passing through the pressure side of the passage and forces the tip leakage flow to spill into the adjacent blade passage from the pressure side at the leading edge. It is found that the tip leakage flow exerts little influence on the development of the blade suction surface boundary layer even at the near stall condition.

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.

1118 Effect of Tip Clearance on Rotating Stall Inception in an Axial Flow Compressor Rotor

2009 ◽  
Vol 2009 (0) ◽  
pp. 377-378 ◽  
Author(s):  
Hiroaki KIKUTA ◽  
Masato FURUKAWA ◽  
Satoshi GUNJISHIMA ◽  
Kenichiro IWAKIRI ◽  
Takuro KAMEDA
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Stall Inception ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor
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