Blade-surface boundary layer and wake computational models for estimation of axial-flow compressor and fan blade-row fluid turning angles and losses

This study presents experimental investigations into blade suction surface boundary layer flow in a multistage axial flow compressor. The experiments were focused on the third stage of the 4-stage Low Speed Research Compressor (LSRC) at Cranfield University. Measurements within the boundary layer were obtained using a hot wire probe. This was traversed normal to the blade surface at small increments, capturing the unsteady velocity profile within the boundary layer. Detailed boundary layer flow measurements covering most of the stator suction surface were taken and are described using time mean and ensemble averaged velocity profiles. Turbulence intensity in the boundary layer flow on the blade suction surface is also discussed. A strong wake-induced strip zone due to passing wake disturbances are generated at midspan near the blade leading edge at rotor blade passing frequency. Corner separation was observed at the tip region near the trailing edge. Normalized velocity profiles in this region show no variation in time.

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Measurement and Analysis of Total-Pressure Unsteadiness Data From an Axial-Flow Compressor Stage

Journal of Engineering for Power ◽

10.1115/1.3227303 ◽

1982 ◽

Vol 104 (2) ◽

pp. 479-488 ◽

Cited By ~ 19

Author(s):

W. C. Zierke ◽

T. H. Okiishi

Keyword(s):

Energy Transfer ◽

Total Pressure ◽

Axial Flow ◽

Fast Response ◽

Pressure Probe ◽

Surface Boundary ◽

Surface Boundary Layer ◽

Blade Row ◽

Measurement And Analysis ◽

Flow Compressor

A fast-response, total-pressure probe was used with a periodically sampling and averaging data acquisition system to study the unsteady total-pressure field in an axial-flow turbomachine. Periodically unsteady total-pressure data were used to demonstrate some of the ways in which turbomachine blade wake transport and interaction influences the energy transfer involved. Observed trends of periodic variations in local total-pressure values could be explained in terms of the details of energy transfer associated with the different kinds of fluid particles (freestream, wake segment, blade surface boundary layer, mixed) moving through a blade row.

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Computation of Secondary Flows in an Axial Flow Compressor Including Inviscid and Viscous Flow Computation

Volume 1: Turbomachinery ◽

10.1115/84-gt-244 ◽

1984 ◽

Author(s):

Francis Leboeuf

Keyword(s):

Boundary Layer ◽

Viscous Flow ◽

Axial Flow ◽

Inviscid Flow ◽

Secondary Flows ◽

Computational Method ◽

Flow Computation ◽

Axial Flow Compressor ◽

Flow Compressor ◽

Highly Loaded

A computational method for secondary flows in a compressor has been extended to treat stalled flows. An integral equation is used which simulates the inviscid flow at the wall, under the viscous flow influence. We present comparisons with experimental results for a 2D stalled boundary layer, and for the secondary flow in a highly loaded stator of an axial flow compressor.

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Influence of Rain Ingestion on the Endwall Treatment in an Axial Flow Compressor

Journal of Turbomachinery ◽

10.1115/1.4040550 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 3

Author(s):

Jichao Li ◽

Juan Du ◽

Mingzhen Li ◽

Feng Lin ◽

Hongwu Zhang ◽

...

Keyword(s):

Rotor Blade ◽

Axial Flow ◽

Pressure Rise ◽

Water Film ◽

Stall Margin ◽

Axial Flow Compressor ◽

Water Ingestion ◽

Blade Row ◽

Flow Compressor ◽

The Stability

The effects of water ingestion on the performance of an axial flow compressor are experimentally studied with and without endwall treatment. The background to the work is derived from the assessment of airworthiness for an aero-engine. The stability-enhancing effects with endwall treatments under rain ingestion are not previously known. Moreover, all the endwall treatments are designed under dry air conditions in the compressor. Water ingestion at 3% and 5% relative to the design mass flow proposed in the airworthiness standard are applied to initially investigate the effects on the performance under smooth casing (SC). Results show that the water ingestions are mainly located near the casing wall after they move through the rotor blade row. The pressure rise coefficient increases, efficiency declines, and torque increases under the proposed water ingestion. The increase of the inlet water increases the thickness of the water film downstream the rotor blade row and aggravates the adverse effects on the performances. Subsequently, three endwall treatments, namely circumferential grooves, axial slots, and hybrid slots–grooves, are tested with and without water ingestion. Compared with no water ingestion, the circumferential grooves basically have no resistance to the water ingestion. The axial slots best prevent the drop of the pressure rise coefficient induced by water ingestion, and hybrid slots–grooves are the second-best place owing to the contribution of the front axial slots. Therefore, the hybrid slots–grooves can not only extend the stall margin with less efficiency penalty compared with axial slots, but also prevent rain ingestion from worsening the compressor performance.

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Inner Workings of Aerodynamic Sweep

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery ◽

10.1115/97-gt-401 ◽

1997 ◽

Cited By ~ 9

Author(s):

A. R. Wadia ◽

P. N. Szucs ◽

D. W. Crall

Keyword(s):

Boundary Layer ◽

Flow Analysis ◽

Three Dimensional ◽

Axial Flow ◽

Tip Clearance ◽

Surface Boundary ◽

Surface Boundary Layer ◽

Stall Margin ◽

Design Speed ◽

The Impact

The recent trend in using aerodynamic sweep to improve the performance of transonic blading has been one of the more significant technological evolutions for compression components in turbomachinery. This paper reports on the experimental and analytical assessment of the pay-off derived from both aft and forward sweep technology with respect to aerodynamic performance and stability. The single stage experimental investigation includes two aft-swept rotors with varying degree and type of aerodynamic sweep and one swept forward rotor. On a back-to-back test basis, the results are compared with an unswept rotor with excellent performance and adequate stall margin. Although designed to satisfy identical design speed requirements as the unswept rotor, the experimental results reveal significant variations in efficiency and stall margin with the swept rotors. At design speed, all the swept rotors demonstrated a peak stage efficiency level that was equal to that of the unswept rotor. However, the forward-swept rotor achieved the highest rotor-alone peak efficiency. At the same time, the forward-swept rotor demonstrated a significant improvement in stall margin relative to the already satisfactory level achieved by the unswept rotor. Increasing the level of aft sweep adversely affected the stall margin. A three-dimensional viscous flow analysis was used to assist in the interpretation of the data. The reduced shock/boundary layer interaction, resulting from reduced axial flow diffusion and less accumulation of centrifuged blade surface boundary layer at the up, was identified as the prime contributor to the enhanced performance with forward sweep. The impact of tip clearance on the performance and stability for one of the aft-swept rotors was also assessed.

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Highly-Loaded Low-Reaction Boundary Layer Suction Axial Flow Compressor

Volume 6: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-28191 ◽

2007 ◽

Cited By ~ 2

Author(s):

Songtao Wang ◽

Xiaoqing Qiang ◽

Weichun Lin ◽

Guotai Feng ◽

Zhongqi Wang

Keyword(s):

Boundary Layer ◽

High Pressure ◽

Pressure Ratio ◽

Axial Flow ◽

Design Concept ◽

Axial Flow Compressor ◽

Boundary Layer Suction ◽

High Pressure Ratio ◽

Flow Compressor ◽

Highly Loaded

In order to design high pressure ratio and highly loaded axial flow compressor, a new design concept based on Highly-Loaded Low-Reaction and boundary layer suction was proposed in this paper. Then the concept’s characteristics were pointed out by comparing with the MIT’s boundary layer suction compressor. Also the application area of this design concept and its key technic were given out in this paper. Two applications were carried out in order to demonstrate the concept. The first application was to redesign a low speed duplication-stage axial flow compressor into a single stage. The second one was a feasibility analysis to decrease an 11 stage axial compressor’s stage count to 7 while not changing its aerodynamic performance. The analysis result showed that the new design concept is feasible and it can be used on high pressure stage of the aero-engine, compressor of ground gas turbine (except the transonic stage) and high total pressure ratio blower.

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Mean Velocity and Decay Characteristics of the Guidevane and Stator Blade Wake of an Axial Flow Compressor

Journal of Engineering for Power ◽

10.1115/1.3230231 ◽

1980 ◽

Vol 102 (1) ◽

pp. 50-60 ◽

Cited By ~ 23

Author(s):

B. Lakshminarayana ◽

R. Davino

Keyword(s):

Axial Flow ◽

Mean Velocity ◽

Axial Flow Compressor ◽

Profile Similarity ◽

Blade Row ◽

Wake Production ◽

Flow Curvature ◽

Stator Blade ◽

Single Sensor ◽

Flow Compressor

Pure tone noise, blade row vibrations, and aerodynamic losses are phenomena which are influenced by stator and IGV blade wake production, decay, and interaction in an axial-flow compressor. The objective of this investigation is to develop a better understanding of the nature of stator and IGV blade wakes that are influenced by the presence of centrifugal forces due to flow curvature. A single sensor hot wire probe was employed to determine the three mean velocity components of stator and IGV wakes of a single stage compressor. These wake profiles indicated a varying decay rate of the tangential and axial wake velocity components and a wake profile similarity. An analysis, which predicts this trend, has been developed. The radial velocities are found to be appreciable in both IGV and the stator wakes. This wake data as well as the data from other sources are correlated in this paper. Appreciable static pressure gradient across the wake is found to exist near the trailing edge of both stator and IGV.

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A Computation and Comparison With Measurements of Transonic Flow in an Axial Compressor Stage With Shock and Boundary Layer Interaction

Journal of Engineering for Power ◽

10.1115/1.3227306 ◽

1982 ◽

Vol 104 (2) ◽

pp. 510-515 ◽

Cited By ~ 5

Author(s):

U. K. Singh

Keyword(s):

Boundary Layer ◽

Mach Number ◽

Axial Flow ◽

Surface Boundary ◽

Compressor Stage ◽

Blade Surface ◽

Layer Interaction ◽

Flow Adjustment ◽

Displacement Thickness ◽

Boundary Layer Interaction

The flow field within a transonic axial flow compressor stage has been computed using a three-dimensional time-marching technique. Limited viscous effects are considered by including a calculation of the blade surface boundary layers. The boundary layer calculation forms an integral part of the whole computation scheme, which consists of, respectively: (i) inviscid Mach number calculations, (ii) blade surface boundary layer displacement thickness calculations, (iii) inviscid Mach number calculations with mass flow adjustment (based on the calculated displacement thicknesses) on the blade surfaces. The boundary layer computation is done by using integral calculation methods and has specifically been developed to account for a shock and boundary layer interaction (should one exist). Comparisons are made with measured results obtained with an advanced laser velocimeter. The calculated Mach number contours are in extremely good agreement with the experimental results. It is concluded that the calculation technique is a useful tool in the design of transonic axial flow turbomachines.

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