Application of Flow Control in a Novel Sector Test Rig

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
Alexander Simpson ◽  
Christian Aalburg ◽  
Michael B. Schmitz ◽  
Robbert Pannekeet ◽  
Vittorio Michelassi ◽  
...  
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Three Dimensional ◽  
Test Rig ◽  
Blow Down ◽  
Radial Compressor ◽  
Injection Flow ◽  
The Matrix ◽  
Return Channel ◽  
Formed Part

An experimental and numerical study has been performed to evaluate the effectiveness of steady injection flow control for the reduction of losses in the return channel of a radial compressor. This investigation formed part of an overall attempt to develop a strategy for reducing the diffusion ratio of radial compressors. It is envisaged that this flow control would be activated at off-design conditions, where separation levels on the return channel vanes are considerable. A novel radial compressor sector test rig, supported by a blow-down facility and equipped with a range of instrumentation, was used for the experimental portion of the study. This allowed multiple flow control configurations to be studied in a simplified environment. A set of exchangeable, inlet guide vanes provide the test vanes with the correct inlet three-dimensional flow-field, while airfoil static pressure taps allowed the blade loading to be assessed. The numerical portion of the study was conducted using 3D-computational fluid dynamics (CFD) and involved simulations of both the sector test rig and a “substitute system”. In this paper, the rationale for the inclusion of flow control in a radial compressor return channel is discussed. The sector test rig is then described, including the implementation of flow control. The results of the matrix of flow control experiments are then discussed with comparison to the numerical results.

Application of Flow Control in a Novel Sector Test Rig

2009 ◽  
Author(s):  
Alexander Simpson ◽  
Christian Aalburg ◽  
Michael Schmitz ◽  
Robbert Pannekeet ◽  
Florian Larisch ◽  
...  
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Three Dimensional ◽  
Test Rig ◽  
Blow Down ◽  
Radial Compressor ◽  
Injection Flow ◽  
The Matrix ◽  
Return Channel ◽  
Formed Part

An experimental and numerical study has been performed to evaluate the effectiveness of steady injection flow control for the reduction of losses in the return channel of a radial compressor. This investigation formed part of an overall attempt to develop a strategy for reducing the diffusion ratio of radial compressors. It is envisaged that this flow control would be activated at off-design conditions where separation levels on the return channel vanes are considerable. A novel radial compressor sector test rig, supported by a blow-down facility and equipped with a range of instrumentation, was used for the experimental portion of the study. This allowed multiple flow control configurations to be studied in a simplified environment. A set of exchangeable, inlet guide vanes provide the test vanes with the correct inlet three-dimensional flow-field whilst airfoil static pressure taps allowed the blade loading to be assessed. The numerical portion of the study was conducted using 3D-CFD and involved simulations of both the sector test rig and a “substitute system”. In this paper the rationale for the inclusion of flow control in a radial compressor return channel is discussed. The sector test rig is then described including the implementation of flow control. The results of the matrix of flow control experiments are then discussed with comparison to the numerical results.

Numerical Study of the Heat Transfer in Micro Gas Turbines

2006 ◽  
Vol 129 (4) ◽  
pp. 835-841 ◽  
Author(s):  
T. Verstraete ◽  
Z. Alsalihi ◽  
R. A. Van den Braembussche
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Numerical Study ◽  
Three Dimensional ◽  
High Heat ◽  
Large Temperature ◽  
Radial Compressor ◽  
Micro Gas Turbine ◽  
High Heat Transfer ◽  
The Impact

This paper presents a numerical investigation of the heat transfer inside a micro gas turbine and its impact on the performance. The large temperature difference between turbine and compressor in combination with the small dimensions results in a high heat transfer causing a drop in efficiency of both components. Present study aims to quantify this heat transfer and to reveal the different mechanisms that contribute to it. A conjugate heat transfer solver has been developed for this purpose. It combines a three-dimensional (3D) conduction calculation inside the rotor and the stator with a 3D flow calculation in the radial compressor, turbine and gap between stator and rotor. The results for micro gas turbines of different size and shape and different material characteristics are presented and the impact on performance is evaluated.

Experimental and Numerical Study of a Subsonic Aspirated Cascade

2012 ◽  
Author(s):  
Antoine Godard ◽  
François Bario ◽  
Stéphane Burguburu ◽  
Francis Lebœuf
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Numerical Study ◽  
Design Method ◽  
Active Flow Control ◽  
Three Dimensional ◽  
Design Feature ◽  
Suction Side ◽  
Compressor Blades ◽  
Pressure Losses

This paper presents the validation of a design method for aspirated compressor blades, combining a passive separation control by blade shaping with an active flow control by aspiration. In a first part, a linear aspirated cascade designed according to this method was built and tested at low speed, without and with aspiration. The latter was only applied on the suction surfaces of the blades. Particle Image Velocimetry measurements performed at mid-span of the cascade, in the central passage, showed a complete reattachment of the separated boundary layer on the suction side of the blade. A flow deflection of approximately 65 degrees was achieved requiring an aspirated mass flow rate of 3.3%. However, boundary layer reattachment is effective in a zone centered at mid-span covering 30% of blade span. Flow visualization revealed large corner separation in the presence of aspiration. This is due to the re-establishment of strong pressure gradient on sidewalls of the cascade. No flow control was applied on these zones for optical access purpose. These secondary-flow regions reduced the diffusion occurring within the cascade by nearly 60% in comparison with the design intent. They also increased the expected level of total pressure losses measured by wake traverses downstream of the cascade. In a second part, numerical simulations of the aforementioned experiment were carried out to help the understanding of the experimental results. The simulations were able to reproduce correctly the characteristic flow features, without and with aspiration, observed and measured during the experiment. Thus, they confirmed the potential of this design method developed for aspirated compressor blades, as well as CFD capabilities to simulate the influence of technological effects like suction slots. A uniform and a non-uniform aspiration distribution along the blade span direction were considered during simulations. Suction distribution was found to have a significant impact on the control by aspiration. This design feature, in addition to flow control on endwalls, has to be taken into account in the three-dimensional design of highly loaded aspirated compressor blades.

An Experimental and Numerical Study of Tip-Leakage Flows in an Idealized Turbine Tip Gap at High Mach Numbers

2018 ◽  
Author(s):  
Maximilian Passmann ◽  
Stefan aus der Wiesche ◽  
Franz Joos
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Blow Down ◽  
Tip Leakage ◽  
Leakage Flows ◽  
Mach Numbers ◽  
High Mach ◽  
Tip Leakage Flows

This paper presents results of a detailed investigation of turbine tip-leakage flows at high Mach numbers. The experimental work was carried out using a small blow-down wind tunnel. An idealized blade test section was used to study blade tip-clearance effects in transonic conditions. Unshrouded blade tips are considered and different tip gap heights are investigated. A high blade exit Mach number of Me = 2 was selected deliberately. While conventional transonic turbine stages generally operate at lower supersonic exit Mach numbers, the conditions are representative for ORC turbines. Both experimental and numerical results are presented in this contribution. The results indicate, that tip leakage flow under transonic conditions leads to a complex three-dimensional flow field. A strong interaction between tip gap vortex and trailing edge shocks was observed, that also had a profound effect on the base region. While no final statement on losses could be made in the present configuration, the results indicate a weakened shock system.

Numerical Investigation of Three-dimensional Separation Control on a High-speed Compressor Stator Vane with Tailored Synthetic Jet

2020 ◽  
Vol 37 (4) ◽  
pp. 383-397 ◽  
Author(s):  
Yong Qin ◽  
Yanping Song ◽  
Ruoyu Wang ◽  
Huaping Liu
Keyword(s):  
Flow Control ◽  
Flow Separation ◽  
High Speed ◽  
Numerical Study ◽  
Three Dimensional ◽  
Synthetic Jet ◽  
Separation Control ◽  
Flow Separation Control ◽  
Control Efficiency ◽  
Stator Vane

AbstractA numerical study on the performance of synthetic jet for flow separation control on a high-speed compressor stator vane is performed. Four control schemes including full-span and part-span configurations are investigated at both design and off-design conditions. Results indicate that both full-span and part-span schemes could effectively delay flow separation and reduce total pressure loss for the compressor stator vane, the adaptability of the flow control under off-design conditions is also validated. Within the investigated incidence range, the full-span configuration is able to gain the most significant performance improvement, by which a maximum loss reduction of 23.8 % is obtained at i=2 deg. The part-span configuration could reorganize the vortex structures more efficiently and cut off the interaction between the ring-like vortex and the passage vortex, thus improving its performance in the corner region. In terms of flow control efficiency, the part-span configurations turn out to be more superior, where the highest control efficiency of 614.0 % is achieved at i=0 deg with the total height of the actuator being 40 %H. The flow control efficiency for all the schemes is higher than 100 % within the whole operating range, demonstrating a promising prospect for the application of synthetic jet in axial compressors.

Design, Validation and Application of a Radial Cascade for Centrifugal Compressors

2008 ◽  
Author(s):  
Alexander Simpson ◽  
Christian Aalburg ◽  
Michael Schmitz ◽  
Robbert Pannekeet ◽  
Florian Larisch ◽  
...  
Keyword(s):  
Design Space ◽  
Three Dimensional ◽  
Measurement Data ◽  
Test Results ◽  
Pressure Loading ◽  
Test Rig ◽  
Three Dimensional Flow ◽  
Blow Down ◽  
Operation Conditions ◽  
Flow Pressure

A novel sector test rig has been used to evaluate a new airfoil concept for multistage radial compressors. The test rig is supported by a blow-down facility where the operation conditions are adjusted by controlling mass flow, pressure and temperature. At inlet to the sector test rig itself a set of adjustable inlet guide vanes provide the test vanes with the correct inlet three-dimensional flow-field. The rig is equipped with instrumentation to allow a detailed description of the inlet and outlet conditions, as well as the blade pressure loading. This rig, using rapid prototyped vanes, allows design candidates to be screened quickly and is ideal for conducting an experimental investigation of a design space using a Design-of-Experiments approach. In this paper the rationale for the sector approach is described, the design of the test rig with 3D-CFD methods is outlined and a detailed validation of the rig is presented. For the vane in question detailed investigations of different operation points close to stall are reported, blade pressures and inlet and exit flow profiles are given. Where applicable, measurement data from the sector rig was compared to 3D-CFD calculations of the full annulus multistage configuration, to 3D-CFD calculations of the sector rig itself and to the test results from a 1.5-stage rotating test rig. The measurement data are compared to the CFD predictions and served as a calibration basis for the design tools.

Inverse Design of Radial Compressor Components by Modern CFD

2000 ◽  
Author(s):  
R. A. Van den Braembussche ◽  
J. Antolin ◽  
R. Thygesen
Keyword(s):  
Velocity Distribution ◽  
Inverse Method ◽  
Three Dimensional ◽  
Inverse Methods ◽  
Inverse Design ◽  
Centrifugal Impeller ◽  
Design Criteria ◽  
Radial Compressor ◽  
Inlet Guide Vanes ◽  
Return Channel

Abstract The use of a three-dimensional inverse method for the design of inlet guide vanes, a centrifugal impeller and return channel is demonstrated. The geometry of the different components are iteratively defined until a prescribed velocity distribution is obtained. The procedure and design criteria for each component are described and the final result is presented. The advantages, disadvantages and problems related to the use of inverse methods are discussed.

Designing TIMP (tissue inhibitor of metalloproteinases) variants that are selective metalloproteinase inhibitors

2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew
Keyword(s):  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Structural Basis ◽  
Structural Elements ◽  
Ridge Structure ◽  
Extracellular Matrix Components ◽  
Metalloproteinase Inhibitors ◽  
The Matrix ◽  
A Disintegrin And Metalloproteinase

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.

EXPERIMENTAL AND NUMERICAL STUDY OF THREE-DIMENSIONAL NATURAL CONVECTION AND FREEZING IN WATER

1994 ◽  
Author(s):  
C. Abegg ◽  
Graham de Vahl Davis ◽  
W.J. Hiller ◽  
St. Koch ◽  
Tomasz A. Kowalewski ◽  
...  
Keyword(s):  
Natural Convection ◽  
Numerical Study ◽  
Three Dimensional
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