Tip clearance vortex development and shock-vortex-interaction in a transonic axial compressor rotor

2002 ◽  
Author(s):  
J. Ballmann ◽  
W. Hofmann
Keyword(s):  
Axial Compressor ◽  
Tip Clearance ◽  
Vortex Interaction ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Tip Clearance Vortex

scholarly journals Experimental and Computational Investigation of the Tip Clearance Flow in a Transonic Axial Compressor Rotor

1996 ◽  
Vol 118 (2) ◽  
pp. 218-229 ◽  
Author(s):  
K. L. Suder ◽  
M. L. Celestina
Keyword(s):  
Axial Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Vortex Interaction ◽  
Peak Efficiency ◽  
Tip Clearance Flow ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Transonic Axial Compressor ◽  
Design Speed

Experimental and computational techniques are used to investigate tip clearance flows in a transonic axial compressor rotor at design and part-speed conditions. Laser anemometer data acquired in the endwall region are presented for operating conditions near peak efficiency and near stall at 100 percent design speed and at near peak efficiency at 60 percent design speed. The role of the passage shock/leakage vortex interaction in generating endwall blockage is discussed. As a result of the shock/vortex interaction at design speed, the radial influence of the tip clearance flow extends to 20 times the physical tip clearance height. At part speed, in the absence of the shock, the radial extent is only five times the tip clearance height. Both measurements and analysis indicate that under part-speed operating conditions a second vortex, which does not originate from the tip leakage flow, forms in the end-wall region within the blade passage and exits the passage near midpitch. Mixing of the leakage vortex with the primary flow downstream of the rotor at both design and part-speed conditions is also discussed.

scholarly journals Experimental and Computational Investigation of the Tip Clearance Flow in a Transonic Axial Compressor Rotor

1994 ◽  
Author(s):  
Kenneth L. Suder ◽  
Mark L. Celestina
Keyword(s):  
Axial Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Vortex Interaction ◽  
Peak Efficiency ◽  
Tip Clearance Flow ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Transonic Axial Compressor ◽  
Design Speed

Experimental and computational techniques are used to investigate tip clearance flows in a transonic axial compressor rotor at design and part speed conditions. Laser anemometer data acquired in the endwall region are presented for operating conditions near peak efficiency and near stall at 100% design speed and at near peak efficiency at 60% design speed. The role of the passage shock / leakage vortex interaction in generating endwall blockage is discussed. As a result of the shock / vortex interaction at design speed, the radial influence of the tip clearance flow extends to 20 times the physical tip clearance height. At part speed, in the absence of the shock, the radial extent is only 5 times the tip clearance height. Both measurements and analysis indicate that under part-speed operating conditions a second vortex, which does not originate from the tip leakage flow, forms in the endwall region within the blade passage and exits the passage near midpitch. Mixing of the leakage vortex with the primary flow downstream of the rotor at both design and part speed conditions is also discussed.

scholarly journals Blockage Development in a Transonic, Axial Compressor Rotor

1997 ◽  
Author(s):  
Kenneth L. Suder
Keyword(s):  
Boundary Layer ◽  
Axial Compressor ◽  
Flow Region ◽  
Tip Clearance ◽  
Surface Boundary ◽  
Core Flow ◽  
The Core ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
The Impact

A detailed experimental investigation to understand and quantify the development of blockage in the flow field of a transonic, axial flow compressor rotor (NASA Rotor 37) has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at 100%, 85%, 80%, and 60% of design speed which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26, 1.18, and 0.89 respectively. The impact of the shock on the blockage development, pertaining to both the shock / boundary layer interactions and the shock / tip clearance flow interactions, is discussed. The results indicate that for this rotor the blockage in the endwall region is 2–3 times that of the core flow region, and the blockage in the core flow region more than doubles when the shock strength is sufficient to separate the suction surface boundary layer.

Numerical Investigation of Relation Between Unsteady Behavior of Tip Leakage Vortex and Rotating Disturbance in a Transonic Axial Compressor Rotor

2008 ◽  
Author(s):  
K. Yamada ◽  
K. Funazaki ◽  
H. Sasaki
Keyword(s):  
Vortex Breakdown ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Tip Leakage Vortex ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Transonic Axial Compressor ◽  
Rotating Instability

The purpose of this study is to have a better understanding of the unsteady behavior of tip clearance flow at near-stall condition from a multi-passage simulation and to clarify the relation between such unsteadiness and rotating disturbance. This study is motivated by the following concern. A single passage simulation has revealed the occurrence of the tip leakage vortex breakdown at near-stall condition in a transonic axial compressor rotor, leading to the unsteadiness of the tip clearance flow field in the rotor passage. These unsteady flow phenomena were similar to those in the rotating instability, which is classified in one of the rotating disturbances. In other words it is possible that the tip leakage vortex breakdown produces a rotating disturbance such as the rotating instability. Three-dimensional unsteady RANS calculation was conducted to simulate the rotating disturbance in a transonic axial compressor rotor (NASA Rotor 37). The four-passage simulation was performed so as to capture a short length scale disturbance like the rotating instability and the spike-type stall inception. The simulation demonstrated that the unsteadiness of tip leakage vortex, which was derived from the vortex breakdown at near-stall condition, invoked the rotating disturbance in the rotor, which is similar to the rotating instability.

Effects of the Steady Wake-Tip Clearance Vortex Interaction in a Compressor Cascade: Part II — Numerical Investigations

2014 ◽  
Author(s):  
Peter Busse ◽  
Andreas Krug ◽  
Konrad Vogeler
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Initial Conditions ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Vortex Interaction ◽  
Compressor Cascade ◽  
Flow Phenomena ◽  
Tip Clearance Vortex ◽  
The Impact

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step towards the characterisation of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. Part II of this two-part paper focuses on the numerical studies conducted with the scientific flow solver TRACE. Selected measurements, which are discussed in detail in the first part of this paper, are compared with steady state RANS simulation data to determine the validity of the computational model. For this purpose, the flow field obtained in the passage (PIV), at the cascade exit (five-hole probes) and the endwall pressure distributions were used. The presented numerical results show potentials and limitations of the steady state CFD for the prediction of the investigated flow phenomena. The computations provide the initial conditions for future unsteady calculations, and enable a separate depiction of potential effects of steady and unsteady wake-tip clearance vortex interaction.

Design and Test of a Transonic Axial Splittered Rotor

2015 ◽  
Author(s):  
Garth V. Hobson ◽  
Anthony J. Gannon ◽  
Scott Drayton
Keyword(s):  
Mass Flow ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Design Procedure ◽  
Tip Clearance ◽  
Turbine Engine ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Commercial Off The Shelf

A new design procedure was developed that uses commercial-off-the-shelf software (MATLAB, SolidWorks, and ANSYS-CFX) for the geometric rendering and analysis of a transonic axial compressor rotor with splitter blades. Predictive numerical simulations were conducted and experimental data were collected in a Transonic Compressor Rig. This study advanced the understanding of splitter blade geometry, placement, and performance benefits. In particular, it was determined that moving the splitter blade forward in the passage between the main blades, which was a departure from the trends demonstrated in the few available previous transonic axial compressor splitter blade studies, increased the mass flow range with no loss in overall performance. With a large 0.91 mm (0.036 in) tip clearance, to preserve the integrity of the rotor, the experimentally measured peak total-to-total pressure ratio was 1.69 and the peak total-to-total isentropic efficiency was 72 percent at 100 percent design speed. Additionally, a higher than predicted 7.5 percent mass flow rate range was experimentally measured, which would make for easier engine control if this concept were to be included in an actual gas turbine engine.

Study of Sloped Trench Casing Treatment on Performance and Stability of a Transonic Axial Compressor

2007 ◽  
Author(s):  
Hui Zhang ◽  
Hongwei Ma
Keyword(s):  
Performance Improvement ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Smooth Transition ◽  
Nasa Lewis Research ◽  
Casing Treatment ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Simulation Results ◽  
A Performance

This paper presents a numerical investigation of effects of sloped trench casing treatment over the rotor tip on the aerodynamic performance and stability of a transonic axial compressor rotor (NASA Rotor 37). The axially cutting tip of blade is the marked characteristic of the casing treatment which is differ with casing treatments without adjustment of the blade tip. The numerical method has been verified by experimental results in the case of the smooth casing with the tip clearance of 0.356 mm at the design wheel speed (17188.7 rpm). The simulation results are well consistent with the measurement results. The experiment results of NASA Rotor 37 cite from NASA Lewis Research Center. The simulation results show a performance improvement of the compressor on the sloped trench casing. The flow fields of the smooth and sloped trench casings were compared, and results show the sloped trench geometry provides a barrier to minimize the forward flow from the tip clearance vortex. In addition, the sloped trench allows the forward facing step at the aft end to be replaced by an aerodynamically smooth transition to guide the flow from the recess into the mainstream. These results show a performance improvement of the compressor.

CFD Code Validation and Qualitative Study of Effects of Tip Clearance Variation on Performance of Transonic Axial Compressor Rotor

2012 ◽  
Author(s):  
Aniket R. Patkar ◽  
Srinivethan Rangasamy ◽  
Sreekanth Raghunath ◽  
Vilas Kalamkar
Keyword(s):  
Pressure Ratio ◽  
Splitting Method ◽  
Flow Characteristics ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Maximum Pressure ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Transonic Axial Compressor ◽  
Multiple Frame

The main objective of this work is the validation of Computational Fluid Dynamics (CFD) code used for analysis of transonic axial compressors. NASA Rotor 35 is used here as test case for validation. In this work, computations are performed using parallelized RANS code, to predict the transonic axial compressor rotor flow characteristics. Advection Upstream Splitting Method (AUSM) scheme has been used. A Multiple Frame of Reference approach has been used to model the rotor passage. Spalart-Allmaras turbulence model is used to model turbulence. Multiblock Structured mesh is used. Performance characteristics for the entire range of operation, from maximum mass flow rate till maximum pressure ratio, have been simulated. The results obtained are comparable with experimental data within 5–10% error. Investigations have been carried out to study the effect of varying tip clearance in NASA Rotor 35. The present work is intended to study the clearance flow trajectory as a function of varying tip clearance. The effects of shock/vortex interaction in tip clearance region are also studied. The effects of tip clearance size on the generation and evolution of the end-wall vortical structures are discussed by investigating their evolutionary trajectories. By this study, it is observed that as tip clearance reduces, clearance flow trajectory moves downstream. From this it can be concluded that if tip clearance increases, tip clearance vortices expand. This may help in casing-treatment or tip-treatment to mitigate the loss in the performance, if the tip clearance increases.

3-D Digital PIV Measurements of the Tip Clearance Flow in an Axial Compressor

2002 ◽  
Author(s):  
Mark P. Wernet ◽  
Dale Van Zante ◽  
Tony J. Strazisar ◽  
W. Trevor John ◽  
P. Susan Prahst
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Compressor Rotor ◽  
Image Velocimetry ◽  
Clearance Flow ◽  
Compressor Performance ◽  
Tip Clearance Vortex

The accurate characterization and simulation of rotor tip clearance flows has received much attention in recent years due to their impact on compressor-performance and stability. At NASA Glenn the first known three dimensional Digital Particle Image Velocimetry (DPIV) measurements of the tip region of a low speed compressor rotor have been acquired to characterize the behavior of the rotor tip clearance flow. The measurements were acquired phase-locked to the rotor position so that changes in the tip clearance vortex position relative to the rotor blade can be seen. The DPIV technique allows the magnitude and relative contributions of both the asynchronous motions of a coherent structure and the temporal unsteadiness to be evaluated. Comparison of measurements taken at the peak efficiency and at near stall operating conditions characterizes the mean position of the clearance vortex and the changes in the unsteady behavior of the vortex with blade loading. Comparisons of the 3-D DPIV measurements at the compressor design point to a 3D steady N-S solution are also done to assess the fidelity of steady, single-passage simulations to model an unsteady flow field.

Blockage Development in a Transonic, Axial Compressor Rotor

1998 ◽  
Vol 120 (3) ◽  
pp. 465-476 ◽  
Author(s):  
K. L. Suder
Keyword(s):  
Boundary Layer ◽  
Axial Compressor ◽  
Flow Region ◽  
Tip Clearance ◽  
Surface Boundary ◽  
Core Flow ◽  
The Core ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
The Impact

A detailed experimental investigation to understand and quantify the development of blockage in the flow field of a transonic, axial flow compressor rotor (NASA Rotor 37) has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at 100, 85, 80, and 60 percent of design speed, which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26, 1.18, and 0.89, respectively. The impact of the shock on the blockage development, pertaining to both the shock/boundary layer interactions and the shock/tip clearance flow interactions, is discussed. The results indicate that for this rotor the blockage in the endwall region is 2–3 times that of the core flow region, and the blockage in the core flow region more than doubles when the shock strength is sufficient to separate the suction surface boundary layer.

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