Three-Dimensional Turbulent Flow Field Downstream of a Single-Stage Axial Compressor Rotor

2000 ◽  
Author(s):  
Hongwei Ma ◽  
Haokang Jiang
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Mass Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Single Stage ◽  
Suction Surface ◽  
Trailing Edge ◽  
Rotor Wake ◽  
Compressor Rotor

This paper reports an experimental investigation of the three-dimensional turbulent flow downstream of a single-stage axial compressor rotor. The flow fields were measured at two axial locations in the rotor-stator gap at different mass-flow conditions. Both hot-wire probe and fast-response pressure probe were employed to survey the flow structure. At the design condition, substantial flow blockage, turbulence, loss and aerodynamic noise mainly occur in the tip mid-passage, the rotor wake and at the hub corner of the suction surface. The radial component is the highest of the three turbulence intensities at 15% axial chord downstream of the trailing edge. With the flow downstream, the radial turbulence components decay fast. Interactions of the tip leakage vorticities and the rotor wake are found at 30% axial chord downstream of the trailing edge. With the mass-flow decrease, the turbulence intensities and shear stresses become stronger, while the radial components increase fast. The flow separation and tangential migration of the low-energy fluids at the tip corner of the suction surface play an important role in the tip flow field at a low mass-flow condition.

Three-Dimensional Turbulent Flow of the Tip Leakage Vortex in an Axial Compressor Rotor Passage

2000 ◽  
Author(s):  
Hongwei Ma ◽  
Haokang Jiang
Keyword(s):  
Turbulent Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Radial Component ◽  
Reynolds Stresses ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Compressor Rotor

Three-dimensional turbulent flow of the tip leakage vortex in a single-stage axial compressor rotor passage is studied using a 3-Component Laser Doppler Velocimetry. The measurement results indicate that the tip leakage vortex originates at about 10% axial chord, 8% pitch away from the suction surface, and becomes strongest at about 30% chord. With the flow downstream, the vortex core moves toward the pressure surface and to a lower radial location, leading to substantial flow mixing, blockage and turbulence in the tip region. The radial component of turbulence intensities is found to be the highest while the axial-radial component of Reynolds stresses is the largest. Breakdown of the leakage vortex occurs inside the rear rotor passage, which makes the flow more turbulent in a wider region downstream. This viewpoint is confirmed by the measurements of unsteady static pressure on the casing wall. Breakdown of a leakage vortex is observed clearly in a compressor cascade with a small clearance. Unsteady interactions of the broken vorticities and the suction surface’s boundary layer are shown obviously inside the downstream passage.

Three-Dimensional Unsteady Flow Field due to IGV-Rotor Interaction in the Tip Region of an Axial Compressor Rotor Passage

2001 ◽  
Author(s):  
Hongwei Ma ◽  
Haokang Jiang ◽  
Qingguo Zhang
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Large Scale ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Low Energy ◽  
Suction Surface ◽  
Compressor Rotor ◽  
Flow Mixing

This paper reports an experimental study of the three-dimensional unsteady flow field due to IGV-rotor interaction in the tip region of an axial compressor rotor passage. The measurements were conducted on a low-speed large-scale axial compressor using a 3-component Laser Doppler Velocimetry. Both experimental method and measurement techniques are presented in details. The results indicate that the tip corner flow of the IGV suction surface has deeper effects on the downstream flow than the IGV wake in the tip region. The interaction and the flow mixing among the IGV wake, the IGV comer flow and the rotor leading-edge flow occur at the inlet of a rotor passage, which make the rotor inlet flow three-dimensional, turbulent and unsteady. The low-energy fluids from the upstream tend to accumulate toward the rotor pressure surface after they enter a rotor passage. In the procedure, the interaction and the flow mixing among the rotor tip leakage vortex and the low-energy fluids occur in the rotor passage.

Unsteady Flow Behavior due to Breakdown of Tip Leakage Vortex in an Axial Compressor Rotor at Near-Stall Condition

2000 ◽  
Author(s):  
Masato Furukawa ◽  
Kazuhisa Saiki ◽  
Kazutoyo Yamada ◽  
Masahiro Inoue
Keyword(s):  
Unsteady Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Surface Boundary ◽  
Pressure Side ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Pressure Surface ◽  
Compressor Rotor

The unsteady flow nature caused by the breakdown of the tip leakage vortex in an axial compressor rotor at near-stall conditions has been investigated by unsteady three-dimensional Navier-Stokes flow simulations. The simulations show that the spiral-type breakdown of the tip leakage vortex occurs inside the rotor passage at the near-stall conditions. Downstream of the breakdown onset, the tip leakage vortex twists and turns violently with time, thus interacting with the pressure surface of the adjacent blade. The motion of the vortex and its interaction with the pressure surface are cyclic. The vortex breakdown causes significant changes in the nature of the tip leakage vortex, which result in the anomalous phenomena in the time-averaged flow fields near the tip at the near-stall conditions: no rolling-up of the leakage vortex downstream of the rotor, disappearance of the casing wall pressure trough corresponding to the leakage vortex, large spread of the low-energy fluid accumulating on the pressure side, and large pressure fluctuation on the pressure side. As the flow rate is decreased, the movement of the tip leakage vortex due to its breakdown becomes so large that the leakage vortex interacts with the suction surface as well as the pressure one. The interaction with the suction surface gives rise to the three-dimensional separation of the suction surface boundary layer.

Three-Dimensional Turbulent Flow in the Tip Region of an Axial Compressor Rotor Passage at a Near Stall Condition

2001 ◽  
Author(s):  
Hongwei Ma ◽  
Haokang Jiang
Keyword(s):  
Turbulent Flow ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Compressor Rotor

This paper presents an experimental study of the three-dimensional turbulent flow field in the tip region of an axial flow compressor rotor passage at a near stall condition. The investigation was conducted in a low-speed large-scale compressor using a 3-component Laser Doppler Velocimetry and a high frequency pressure transducer. The measurement results indicate that a tip leakage vortex is produced very close to the leading edge, and becomes the strongest at about 10% axial chord from the leading edge. Breakdown of the vortex periodically occurs at about 1/3 chord, causing very strong turbulence in the radial direction. Flow separation happens on the tip suction surface at about half chord, prompting the corner vortex migrating toward the pressure side. Tangential migration of the low-energy fluids results in substantial flow blockage and turbulence in the rear of a rotor passage. Unsteady interactions among the tip leakage vortex, the separated vortex and the corner flow should contribute to the inception of the rotating stall in a compressor.

Impact of Sweep on Part Speed Performance of an Axial Compressor Rotor With Circumferential Casing Grooves

2019 ◽  
Author(s):  
Shraman Goswami ◽  
M. Govardhan
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Field Investigation ◽  
Performance Comparison ◽  
Rotor Blades ◽  
Stall Margin ◽  
Compressor Rotor ◽  
Design Speed

Abstract High performance and increased operating range of an axial compressor is obtained by employing three-dimensional design features, such as sweep, as well as shroud casing treatments, such as circumferential casing grooves. A number of different rotor blades with different amounts of sweeps and different sweep starting spans are studied at design speed. Different swept rotors, including zero sweep, are derived from Rotor37 rotor geometry. In the current study the best performing rotor with sweep is analyzed at part speed. The analyses were done for baseline rotor, devoid of any sweep, and with and without circumferential casing grooves. A detailed flow field investigation and performance comparison is presented to understand the changes in flow field at part speed. It is found that that at 100% design speed, stall margin improvement is achived by both sweep and casing grooves, but at 90% speed improvement in stall margin due to sacing groove is very minimal over and above the gain due to sweep. It is also noticed that due to reduced shock loss efficiency is higher at 90% speed than at 100% speed.

Unsteady Three-Dimensional Flow Phenomena Due to Breakdown of Tip Leakage Vortex in a Transonic Axial Compressor Rotor

2004 ◽  
Author(s):  
K. Yamada ◽  
M. Furukawa ◽  
T. Nakano ◽  
M. Inoue ◽  
K. Funazaki
Keyword(s):  
Shock Wave ◽  
Flow Field ◽  
Vortex Breakdown ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Leading Edge ◽  
Tip Leakage Flow ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Compressor Rotor

Unsteady three-dimensional flow fields in a transonic axial compressor rotor (NASA Rotor 37) have been investigated by unsteady Reynolds-averaged Navier-Stokes simulations. The simulations show that the breakdown of the tip leakage vortex occurs in the compressor rotor because of the interaction of the vortex with the shock wave. At near-peak efficiency condition small bubble-type breakdown of the tip leakage vortex happens periodically and causes the loading of the adjacent blade to fluctuate periodically near the leading edge. Since the blade loading near the leading edge is closely linked to the swirl intensity of the tip leakage vortex, the periodic fluctuation of the blade loading leads to the periodic breakdown of the tip leakage vortex, resulting in self-sustained flow oscillation in the tip leakage flow field. However, the tip leakage vortex breakdown is so weak and small that it is not observed in the time-averaged flow field at near-peak efficiency condition. On the other hand, spiral-type breakdown of the tip leakage vortex is caused by the interaction between the vortex and the shock wave at near-stall operating condition. The vortex breakdown is found continuously since the swirl intensity of tip leakage vortex keeps strong at near-stall condition. The spiral-type vortex breakdown has the nature of self-sustained flow oscillation and gives rise to the large fluctuation of the tip leakage flow field, in terms of shock wave location, blockage near the rotor tip and three-dimensional separation structure on the suction surface. It is found that the breakdown of the tip leakage vortex leads to the unsteady flow phenomena near the rotor tip, accompanying large blockage effect in the transonic compressor rotor at the near-stall condition.

Through-Flow Modeling of Axial Turbomachinery

1985 ◽  
Author(s):  
Robert P. Dring ◽  
H. David Joslyn
Keyword(s):  
Flow Field ◽  
Boundary Layers ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Single Stage ◽  
Strong Impact ◽  
Flow Modeling ◽  
Aerodynamic Design ◽  
Rotor Wake ◽  
Through Flow

Through-flow analysis, which is at the heart of the aerodynamic design of turbomachinery, requires as aerodynamic input a row-by-row description of the airfoil loss, deviation, and blockage. Loss and deviation have been investigated extensively in both cascades and rotating rigs as well as in numerous two- and three-dimensional analytical studies. Blockage, however, has received far less attention. As defined herein, blockage is a measure of the departure of the flow field from the condition of axisymmetry which is assumed in the through-flow analysis. The fullspan blockage distributions calculated from measured single-stage rotor wake data were used to provide the input to the through-flow analysis, along with the measured fullspan distributions of loss and deviation. Measured and computed results are compared for the single-stage rotor operating with both thick and thin inlet hub and tip boundary layers. It is demonstrated that both the level and the spanwise and streamwise distributions of blockage have a strong impact on the computed rotor exit flow field.

scholarly journals A Passive Control Method of Hub Corner Stall in a 1.5-Stage Axial Compressor under Low-Speed Conditions

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2691 ◽  
Author(s):  
Wenfeng Zhao ◽  
Qun Zheng ◽  
Bin Jiang ◽  
Aqiang Lin
Keyword(s):  
Flow Field ◽  
Passive Control ◽  
Control Method ◽  
Axial Compressor ◽  
Field Analysis ◽  
Suction Surface ◽  
Low Speed ◽  
Surface Separation ◽  
Compressor Rotor ◽  
Characteristic Lines

Since the use of the compressor of a ship gas turbine is unavoidable at a low-speed operation, the flow field characteristics and stall mechanism at off-design speeds are important aspects for compressor designers. In this study, the first 1.5 stages of an eight-stage compressor are numerically simulated. The mechanism of compressor rotor instability at lower speeds is identified. The characteristic lines of compressors with various partial clearance are calculated at low speed (0.6 N). The flow field of the same outlet pressure (near stall point of the original compressor without clearance) is compared and analyzed. The results show that, at the near stall point, the suction surface separation and backflow occur in the main flow of the rotor top. It develops along the blade span and finally blocks the flow passage of the rotor, which results in the compressor stall. At the same time, the stall also occurs at the corner of the stator hub. In this paper, the characteristics of partial clearance in four different positions of the stator hub are analyzed. The near stall point and the working point are selected for the flow field analysis. It is concluded that the radial development of the stall vortex on the suction surface of the stator can be restrained by the partial clearance at the stator. In this paper, a passive control method by partial clearance is used in the real compressors, which is different from previous studies on cascades. The margin increases at low speeds.

Numerical Study on Three-Dimensional Optimization of a Low-Speed Axial Compressor Rotor

2014 ◽  
Author(s):  
Chenkai Zhang ◽  
Jun Hu ◽  
Zhiqiang Wang ◽  
Chao Yin ◽  
Wei Yan
Keyword(s):  
Numerical Optimization ◽  
Large Scale ◽  
Numerical Study ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Trailing Edge ◽  
Compressor Rotor ◽  
Flow Loss

This paper presents numerical optimization of a compressor rotor, to deepen the knowledge of endwall flow in the large-scale axial subsonic compressor, accordingly reduce its endwall loss and improve its aerodynamic performance. With numerical simulation and numerical optimization tools, three-dimensional stacking principle is optimized to improve the design operation point performance for the rotor. Results show that, hub region of the rotor cannot undertake large blade loading; compared to the prototype rotor, obvious aerodynamic performance improvements locate near the hub area, and a certain degree of positive dihedral in this region effectively helps to reduce its flow loss. The effect of “loaded leading edge and unloaded trailing edge” due to positive dihedral was shown, which suppresses flow separation near the trailing edge, consequently obviously reduces the flow loss and largely improves the rotor aerodynamic performance.

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