Large-Scale DES Analysis of Unsteady Flow Field in a Transonic Axial Compressor

2016 ◽  
Vol 2016 (0) ◽  
pp. J0520201
Author(s):  
Yuki TAMURA ◽  
Seishiro SAITO ◽  
Masato FURUKAWA ◽  
Kazutoyo YAMADA ◽  
Akinori MATUOKA ◽  
...  
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Large Scale ◽  
Axial Compressor ◽  
Transonic Axial Compressor

Flow Structure and Unsteady Behavior of Hub-Corner Separation in a Stator Cascade of a Multi-Stage Transonic Axial Compressor

2018 ◽  
Author(s):  
Seishiro Saito ◽  
Kazutoyo Yamada ◽  
Masato Furukawa ◽  
Keisuke Watanabe ◽  
Akinori Matsuoka ◽  
...  
Keyword(s):  
Data Mining ◽  
Flow Field ◽  
Unsteady Flow ◽  
Axial Compressor ◽  
Flow Fields ◽  
Suction Surface ◽  
Corner Separation ◽  
High Loss ◽  
Stator Blade ◽  
Transonic Axial Compressor

This paper describes unsteady flow phenomena of a two-stage transonic axial compressor, especially the flow field in the first stator. The stator blade with highly loaded is likely to cause a flow separation on the hub, so-called hub-corner separation. The flow mechanism of the hub-corner separation in the first stator is investigated in detail using a large-scale detached eddy simulation (DES) conducted for its full-annulus and full-stage with approximately 4.5 hundred million computational cells. The detailed analysis of complicated flow fields in the compressor is supported by data mining techniques. The data mining techniques applied in the present study include vortex identification based on the critical point theory and topological analysis of the limiting streamline pattern. The simulation results show that the flow field in the hub-corner separation is dominated by a tornado-type separation vortex. In the time averaged flow field, the hub-corner separation vortex rolls up from the hub wall, which is generated by the interaction between the mainstream flow, the leakage flow from the front partial clearance and the secondary flow across the blade passage toward the stator blade suction side. The hub-corner separation vortex suffers a vortex breakdown near the mid chord, where the high loss region due to the hub-corner separation expands drastically. In the rear part of the stator passage, a high loss region is migrated radially outward by the induced velocity of the hub-corner separation vortex. The flow field in the stator is influenced by the upstream and downstream rotors, which makes it difficult to understand the unsteady effects. The unsteady flow fields are analyzed by applying the phase-locked ensemble averaging technique. It is found from the phase-locked flow fields that the wake interaction from the upstream rotor has more influence on the stator flow field than the shock wave interaction from the downstream rotor. In the unsteady flow field, a focal-type separation also emerges on the blade suction surface, but it is periodically swept away by the wake passing of the upstream rotor. The separation vortex on the hub wall connects with the one on the blade suction surface, forming an arch-like vortex.

Analysis of the Inter-Row Flow Field Within a Transonic Axial Compressor: Part 2 — Unsteady Flow Analysis

2000 ◽  
Author(s):  
Xavier Ottavy ◽  
Isabelle Trébinjac ◽  
André Vouillarmet
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Flow Analysis ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotor Blades ◽  
Time Averaging ◽  
Flow Phenomena ◽  
Order Of Magnitude ◽  
Transonic Axial Compressor

An analysis of the experimental data, obtained by laser two-focus anemometry in the IGV-rotor inter-row region of a transonic axial compressor, is presented with the aim of improving the understanding of the unsteady flow phenomena. A study of the IGV wakes and of the shock waves emanating from the leading edge of the rotor blades is proposed. Their interaction reveals the increase in magnitude of the wake passing through the moving shock. This result is highlighted by the streamwise evolution of the wake vorticity. Moreover, the results are analyzed in terms of a time averaging procedure and the purely time-dependent velocity fluctuations which occur are quantified. It may be concluded that they are of the same order of magnitude as the spatial terms for the inlet rotor flow field. That shows that the temporal fluctuations should be considered for the 3D rotor time-averaged simulations.

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.

Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 2—Unsteady Flow Analysis

2000 ◽  
Vol 123 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Xavier Ottavy ◽  
Isabelle Tre´binjac ◽  
Andre´ Vouillarmet
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotor Blades ◽  
Time Averaging ◽  
Order Of Magnitude ◽  
Transonic Axial Compressor

An analysis of the experimental data, obtained by laser two-focus anemometry in the IGV-rotor interrow region of a transonic axial compressor, is presented with the aim of improving the understanding of the unsteady flow phenomena. A study of the IGV wakes and of the shock waves emanating from the leading edge of the rotor blades is proposed. Their interaction reveals the increase in magnitude of the wake passing through the moving shock. This result is highlighted by the streamwise evolution of the wake vorticity. Moreover, the results are analyzed in terms of a time-averaging procedure and the purely time-dependent velocity fluctuations that occur are quantified. It may be concluded that they are of the same order of magnitude as the spatial terms for the inlet rotor flow field. That shows that the temporal fluctuations should be considered for the three-dimensional rotor time-averaged simulations.

Study of the Standard k-ε Model for Tip Leakage Flow in an Axial Compressor Rotor

2016 ◽  
Vol 33 (4) ◽  
Author(s):  
Yanfei Gao ◽  
Yangwei Liu ◽  
Luyang Zhong ◽  
Jiexuan Hou ◽  
Lipeng Lu
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Turbulent Viscosity ◽  
Axial Compressor ◽  
Leakage Flow ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor

AbstractThe standard k-ε model (SKE) and the Reynolds stress model (RSM) are employed to predict the tip leakage flow (TLF) in a low-speed large-scale axial compressor rotor. Then, a new research method is adopted to “freeze” the turbulent kinetic energy and dissipation rate of the flow field derived from the RSM, and obtain the turbulent viscosity using the Boussinesq hypothesis. The Reynolds stresses and mean flow field computed on the basis of the frozen viscosity are compared with the results of the SKE and the RSM. The flow field in the tip region based on the frozen viscosity is more similar to the results of the RSM than those of the SKE, although certain differences can be observed. This finding indicates that the non-equilibrium turbulence transport nature plays an important role in predicting the TLF, as well as the turbulence anisotropy.

Unsteady Turbine Rim Sealing and Vane Trailing Edge Flow Effects

2021 ◽  
Author(s):  
Iván Monge-Concepción ◽  
Shawn Siroka ◽  
Reid A. Berdanier ◽  
Michael D. Barringer ◽  
Karen A. Thole ◽  
...  
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Rotational Speed ◽  
Large Scale ◽  
Trailing Edge ◽  
Time Resolved ◽  
Flow Rates ◽  
Large Scale Structures ◽  
Purge Flow ◽  
Scale Structures

Abstract Hot gas ingestion into the turbine rim seal cavity is an important concern for engine designers. To prevent ingestion, rim seals use high pressure purge flow but excessive use of the purge flow decreases engine thermal efficiency. A single stage test turbine operating at engine-relevant conditions with real engine hardware was used to study time-resolved pressures in the rim seal cavity across a range of sealing purge flow rates. Vane trailing edge (VTE) flow, shown previously to be ingested into the rim seal cavity, was also included to understand its effect on the unsteady flow field. Measurements from high-frequency response pressure sensors in the rim seal and vane platform were used to determine rotational speed and quantity of large-scale structures (cells). In a parallel effort, a computational model using Unsteady Reynolds-averaged Navier-Stokes (URANS) was applied to determine swirl ratio in the rim seal cavity and time-resolved rim sealing effectiveness. The experimental results confirm that at low purge flow rates, the VTE flow influences the unsteady flow field by decreasing pressure unsteadiness in the rim seal cavity. Results show an increase in purge flow increases the number of unsteady large-scale structures in the rim seal and decreases their rotational speed. However, VTE flow was shown to not significantly change the cell speed and count in the rim seal. Simulations point to the importance of the large-scale cell structures in influencing rim sealing unsteadiness, which is not captured in current rim sealing predictive models.

Numerical Investigation on Internal Flow Field of a Single-Stage Transonic Axial Compressor

2012 ◽  
Vol 15 (6) ◽  
pp. 85-91
Author(s):  
Ji-Han Song ◽  
Oh-Sik Hwang ◽  
Tae Choon Park ◽  
Byung-Jun Lim ◽  
Soo-Seok Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Investigation ◽  
Axial Compressor ◽  
Internal Flow ◽  
Single Stage ◽  
Transonic Axial Compressor

Experimental Investigation of the Steady and Unsteady Flow Field in a Single Stage Low Pressure Axial Compressor With a Circumferential Groove Casing Treatment

2010 ◽  
Author(s):  
N. Van de Wyer ◽  
B. Farkas ◽  
J. Desset ◽  
J. F. Brouckaert ◽  
J.-F. Thomas ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Unsteady Flow ◽  
Axial Compressor ◽  
Low Pressure ◽  
Fast Response ◽  
Single Stage ◽  
Compressor Stage ◽  
Casing Treatment ◽  
Circumferential Groove

This paper deals with the experimental investigation of the influence of a circumferential groove casing treatment on the performance and stability margin of a single stage low pressure axial compressor. The design of the compressor stage is representative of a booster stage for the new counter-rotating turbofan engine architecture and is characterized by unusually high loading and flow coefficients. The choice of the circumferential groove is described on the basis of a numerical parametric study on the number of grooves, the axial position, the depth and width of the groove. The experiments were performed at a Reynolds number corresponding to cruise conditions in the von Karman Institute closed loop high speed compressor test rig R4. The detailed performance characterization of the compressor stage with casing treatment was mapped at four operating points from choke to stall at design speed. The compressor stall limit was determined at several other off-design speeds. Detailed steady and unsteady measurements were performed to determine the flow field characteristics of the rotor and of the complete stage. Conventional pressure, temperature and directional probes were used along with fast response pressure sensors in the rotor casing and in the groove. Simultaneous traverses with a fast response total pressure probe were used to map the unsteady flow field at the rotor exit allowing an experimental capture of the tip leakage vortex path and extension through the rotor passage. A comparison of the flow features with and without casing treatment was performed and the results are discussed against 3D viscous computational predictions. The casing treatment did not present any improvement of the compressor stall margin but no significant performance degradation was observed either. The CFD predictions showed a good agreement with the measurements and their analysis supported the experimental results.

scholarly journals Influence of Unsteady Effects on the Measurements in a Transonic Axial Compressor

1991 ◽  
Author(s):  
Jacques Paulon ◽  
Zhifang Zhang ◽  
Pingfang Jia ◽  
Jingfei Meng
Keyword(s):  
Flow Field ◽  
Relative Position ◽  
Axial Compressor ◽  
Compressor Stage ◽  
Transonic Compressor ◽  
Flow Parameters ◽  
Transonic Axial Compressor ◽  
Unsteady Effects ◽  
Computation Codes ◽  
Interaction Phenomena

Interaction phenomena between rotor and stator are unavoidable in advanced compressors and their effects increase with the performances of the turbomachines. Until now, it was not possible to quantify the interaction effects, but with the development of 3-D unsteady computation codes in a complete stage, it is possible to know, in detail, the flow field through the machine and to make evident and to explain the difficulties encountered in measuring the flow parameters. A study has been conducted in this way at ONERA, on an axial transonic compressor stage. The computations have been made with a simulation of the losses; in this manner, the overall computed and measured performances of the compressor are the same. A detailed analysis of the unsteady computation results makes evident, between rotor and stator, large variations of some parameters of the flow as a function of time but also as a function of the axial and tangential relative position of steady probes and stator blades. Unsteady measurements made on another transonic machine confirm the indications given by these computations.

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