Investigations on a Radial Compressor Tandem-Rotor Stage With Adjustable Geometry

1993 ◽  
Vol 115 (3) ◽  
pp. 552-559 ◽  
Author(s):  
B. Josuhn-Kadner ◽  
B. Hoffmann
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Radial Compressor ◽  
Design Point ◽  
Small Influence ◽  
Point Condition ◽  
And Performance ◽  
Operating Points

A radial compressor stage has been investigated mainly experimentally for aerodynamic stage optimization. The rotor (πt = 3.9) consists of a profiled axial inducer and a conventionally designed radial impeller. Inducer and impeller can be locked at different circumferential positions relative to each other, thus forming a tandem wheel with adjustable geometry. Conventional and Laser-2-Focus system measurements for the tandem rotor and the stage were performed at different operating points to study the influence of the circumferential clearance geometry between inducer and impeller with respect to compressor characteristics and performance. Furthermore, three-dimensional Navier–Stokes calculations are being developed at design point condition to analyze the flow field. A small influence of the inducer adjustment on the rotor characteristics is observed. The maximum rotor efficiency of 93.5 percent varies in a range of less than 1 percent depending on the different inducer positions.

Investigations on a Radial Compressor Tandem-Rotor Stage With Adjustable Geometry

1992 ◽  
Author(s):  
B. Josuhn-Kadner ◽  
B. Hoffmann
Keyword(s):  
Flow Field ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Radial Compressor ◽  
Design Point ◽  
Small Influence ◽  
Point Condition ◽  
And Performance ◽  
Operating Points

A radial compressor stage has been investigated mainly experimentally for aerodynamic stage optimization. The rotor (πt = 3.9) consists of a profiled axial inducer and a conventionally designed radial impeller. Inducer and impeller can be locked at different circumferential positions relative to each other thus, forming a tandem wheel with adjustable geometry. Conventional and Laser-2-Focus system measurements for the tandem-rotor and the stage were performed at different operating points to study the influence of the circumferential clearance geometry between inducer and impeller with respect to compressor characteristics and performance. Furthermore, 3-D Navier-Stokes calculations are being developed at design point condition to analyse the flow field. Small influence of the inducer adjustment on the rotor characteristics is observed. The maximum rotor efficiency of 93.5 % varies in a range of less than 1 % depending on the different inducer positions.

Flow Field Unsteadiness in the Tip Region of a Transonic Compressor Rotor

1997 ◽  
Vol 119 (1) ◽  
pp. 122-128 ◽  
Author(s):  
S. L. Puterbaugh ◽  
W. W. Copenhaver
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Vortex Interaction ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Operating Points

An experimental investigation concerning tip flow field unsteadiness was performed for a high-performance, state-of-the-art transonic compressor rotor. Casing-mounted high frequency response pressure transducers were used to indicate both the ensemble averaged and time varying flow structure present in the tip region of the rotor at four different operating points at design speed. The ensemble averaged information revealed the shock structure as it evolved from a dual shock system at open throttle to an attached shock at peak efficiency to a detached orientation at near stall. Steady three-dimensional Navier Stokes analysis reveals the dominant flow structures in the tip region in support of the ensemble averaged measurements. A tip leakage vortex is evident at all operating points as regions of low static pressure and appears in the same location as the vortex found in the numerical solution. An unsteadiness parameter was calculated to quantify the unsteadiness in the tip cascade plane. In general, regions of peak unsteadiness appear near shocks and in the area interpreted as the shock-tip leakage vortex interaction. Local peaks of unsteadiness appear in mid-passage downstream of the shock-vortex interaction. Flow field features not evident in the ensemble averaged data are examined via a Navier-Stokes solution obtained at the near stall operating point.

Effects of Bowed Stators on a Transonic Fan With Distorted Inlet

2008 ◽  
Author(s):  
Peng Sun ◽  
Ji’ang Han ◽  
Jingjun Zhong ◽  
Liquan Tao ◽  
Muxiao Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Navier Stokes ◽  
3D Analysis ◽  
Navier Stokes Equation ◽  
Design Point ◽  
Fan Performance ◽  
Flow Loss ◽  
Transonic Fan ◽  
Software Pack

The adverse impacts of inlet distortion on fan/compressor have been recognized as an important problem for several decades, and it is still a topic of considerable interest. Many research works indicate that it is possible to improve the performance and stability of a fan in clean and distorted inlet flow by using bowed stator blades. But, how bowed stator influences the flow field and what kind of bow patterns and angles can improve fan performance better are still not clearly studied. Therefore, a 3D analysis in fan flow field with different bowed stator blades is required. In this paper, a time-dependent three-dimensional Reynolds averaged Navier-Stokes equation composed in “Fluent Software Pack” is carried out in a parallel supercomputer. The fan with straight/different bowed stators is simulated with a clean/distorted inlet boundary condition to obtain a better understanding of bowed stators effects in distorted flow field. The analysis of results consists of three aspects. The first is about the effects of straight/bowed stators on the fan characteristics with clean and distorted inlet. Bowed stators can improve the fan performance significantly when inlet is distorted, especially at design point. But, when inlet is clean bowed stators even worsen the fan performance at design point. The effects of bowed stators on the fan performance at design point are analyzed secondly. It is found that different bow angles have different influence on rotor or stator flow field. Small bow angle stator reduces the flow loss in rotor but have no effect on stator flow field. Large bow angle stator can reduce the flow loss in stator markedly, but increases the rotor loss. Finally the patterns of flow loss caused by total pressure distortion with straight and different bowed stators are compared and analyzed in detail. The scale of vortex in stator is weakened by large bow angle blades significantly, which decreased the stator loss.

Optimization of a Diffuser With Splitter by Numerical Simulation

1993 ◽  
Author(s):  
P. Drtina ◽  
P. Dalbert ◽  
K. Rütti ◽  
A. Schachenmann
Keyword(s):  
Numerical Simulation ◽  
Compressible Flow ◽  
Three Dimensional ◽  
Design Procedure ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Recovery Coefficient ◽  
Radial Compressor ◽  
Operating Points ◽  
Pressure Recovery Coefficient

Three-dimensional, viscous, and compressible flow calculations have been performed in order to improve the performance of a radial compressor diffuser with splitter. All calculations were carried out applying a commercially available finite-volume Navier-Stokes code. Diffuser design procedure, grid generation and boundary conditions are described in detail. For each diffuser type several operating points ranging from the surge limit to choke were considered. Velocity distributions showing regions of separation are discussed for different diffuser geometries. The downstream evolution of the pressure recovery coefficient is given along both diffuser channels. Calculations have been verified by experimental investigations on full scale diffuser prototypes providing pressure values at defined locations.

Effects of Bowed Stator on a Fan Characteristic With Distorted Inlet

2010 ◽  
Author(s):  
Peng Sun ◽  
Jingjun Zhong ◽  
Muxiao Yang ◽  
Shaobing Han
Keyword(s):  
Flow Field ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Stall Margin ◽  
Design Point ◽  
Fan Performance ◽  
Flow Loss

The adverse impacts of inlet distortion on fan/compressor have been recognized as an important problem for several decades. But it is still a topic of considerable interest. Prior work has proved, in distorted flow field, bowed stators can constrain separation and reduce flow loss. Different bow patterns and angles influence the fan/compressor in different way. But the above work was carried out only at the design point. How bowed stators influence the fan/compressor performance and stability at other operating conditions is still not clearly studied. Therefore, a deeper research work is required. In this paper, a time-dependent three-dimensional Reynolds averaged Navier-Stokes equation composed in “Fluent Software Pack” is carried out in a parallel supercomputer. A fan with straight/30° bowed stators is simulated with a clean/distorted inlet boundary condition at different operating conditions to obtain the fan characteristic. Two main aspects are contained in this paper. The first is about the effects of straight/bowed stators on the fan characteristics with clean and distorted inlet at different operating point. It is found that 30° bowed stator will worsen the fan performance at most operating conditions with clean inlet. But, when inlet is distorted, it can improve the fan performance and increase the stall margin obviously. The effects of bowed stators on the fan performance and flow field at near stall and design point are analyzed secondly. The fan stability and the anti-distortion capability can be improved by using bowed stator when the inlet total pressure is non-uniform.

Experimental and numerical investigation of the flow field in a high-pressure centrifugal compressor impeller near surge

2009 ◽  
Vol 223 (6) ◽  
pp. 657-666 ◽  
Author(s):  
N Bulot ◽  
I Trébinjac ◽  
X Ottavy ◽  
P Kulisa ◽  
G Halter ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Peak Efficiency ◽  
Vaned Diffuser

Numerical and experimental investigations were conducted in a transonic centrifugal compressor stage composed of a backswept splittered unshrouded impeller and a vaned diffuser. The present article focuses on the results obtained within the impeller, at an operating condition close to the surge of the compressor. The experimental results were obtained from a laser Doppler anemometry investigation. Unsteady numerical simulations of the compressor stage were performed using a three-dimensional Reynolds-averaged Navier—Stokes code with a phase-lagged technique, at both peak efficiency and close to surge operating conditions. A good agreement between the experiments and simulations were obtained, which justifies the use of the computational fluid dynamics results for the comparison of the flow field at both operating conditions (peak efficiency and near surge). Even if the change in flow field within the impeller from peak efficiency to near surge looked to be gradual, an overall rotation of the whole flow in the blade passages led to a non-homogeneous flow at the impeller exit in terms of angle and velocity level. Therefore, the vaned diffuser has to tolerate upstream flows, which are all the more distorted as the operating point moves towards surge.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

Aerothermal Investigation of a Rib-Roughened Trailing Edge Channel With Crossing-Jets—Part I: Flow Field Analysis

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Alessandro Armellini ◽  
Filippo Coletti ◽  
Tony Arts ◽  
Christophe Scholtes
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Side Wall ◽  
Field Analysis ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Present Contribution ◽  
Cross Sectional ◽  
Numerical Predictions ◽  
Rib Roughened

The present contribution addresses the aerothermal, experimental, and computational studies of a trapezoidal cross-sectional model simulating a trailing edge cooling cavity with one rib-roughened wall. The flow is fed through tilted slots on one side wall and exits through straight slots on the opposite side wall. The flow field aerodynamics is investigated in Part I of the paper. The reference Reynolds number is defined at the entrance of the test section and set at 67,500 for all the experiments. A qualitative flow model is deduced from surface-streamline flow visualizations. Two-dimensional particle image velocimetry measurements are performed in several planes around midspan of the channel and recombined to visualize and quantify three-dimensional flow features. The crossing-jets issued from the tilted slots are characterized and the jet-rib interaction is analyzed. Attention is drawn to the motion of the flow deflected by the rib-roughened wall and impinging on the opposite smooth wall. The experimental results are compared with the numerical predictions obtained from the finite volume Reynolds-averaged Navier–Stokes solver, CEDRE.

Numerical Simulation of Clocking Effect on Wake Transportation and Interaction in a 1.5-Stage Axial Turbine

2010 ◽  
Author(s):  
Wei Li ◽  
Hua Ouyang ◽  
Zhao-hui Du
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Leading Edge ◽  
Navier Stokes ◽  
Maximum Efficiency ◽  
Suction Surface ◽  
Navier Stokes Equations ◽  
Pressure Surface ◽  
Turbine Efficiency ◽  
Small Influence

To give insight into the clocking effect and its influence on the wake transportation and its interaction, the unsteady three-dimensional flow through a 1.5-stage axial low pressure turbine is simulated numerically using a density-correction based, Reynolds-Averaged Navier-Stokes equations commercial CFD code. The 2nd stator clocking is applied over ten equal tangential positions. The results show that the harmonic blade number ratio is an important factor affecting the clocking effect. The clocking effect has a very small influence on the turbine efficiency in this investigation. The efficiency difference between the maximum and minimum configuration is nearly 0.1%. The maximum efficiency can be achieved when the 1st stator wake enters the 2nd stator passage near blade suction surface and its adjacent wake passes through the 2nd stator passage close to blade pressure surface. The minimum efficiency appears if the 1st stator wake impinges upon the leading edge of the 2nd stator and its adjacent wake of the 1st stator passed through the mid-channel in the 2nd stator.

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