Effects of Manufacturing Noise on Microturbine Centrifugal Impeller Performance

2012 ◽  
Author(s):  
A. Javed ◽  
R. Pecnik ◽  
M. Olivero ◽  
J. P. van Buijtenen
Keyword(s):  
Performance Analysis ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Analysis Tool ◽  
Modeling Tools ◽  
Output Performance ◽  
1D Model ◽  
The Impact

This paper presents a study on a small centrifugal impeller for microturbine application from a manufacturing perspective. The aim is to analyze the impact of geometric deviations on part performance using adequate performance modeling tools and statistical methods. A one-dimensional (1D) performance analysis tool has been developed in-house derived from the meanline and two-zone modeling methods. The 1D model has proved to be a simple and computationally inexpensive tool for having a quick performance analysis of the impeller using basic geometric information extracted from part drawings. For the sensitivity analysis, a total of eight input geometric parameters including radii, tip-clearance and blade angles have been varied individually within specific limits in the 1D tool for classifying their influence on the output performance. Since the 1D model is a simplified version of a much complex three-dimensional (3D) model, a commercial computational fluid dynamics (CFD) tool has been used to provide a comparison with the 1D model and scrutinize the effects of such deviations on the fluid behavior inside the impeller passage at a detailed level. For uncertainty quantification, Monte Carlo simulation has been performed using the 1D model to assess the variability of overall impeller output performance to simultaneous random deviations in the input geometric parameters. The study is useful to evaluate the possibility of designing gas turbine parts for manufacturability and superior production cost-effectiveness.

Effects of Manufacturing Noise on Microturbine Centrifugal Impeller Performance

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
A. Javed ◽  
R. Pecnik ◽  
M. Olivero ◽  
J. P. van Buijtenen
Keyword(s):  
Performance Analysis ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Analysis Tool ◽  
Modeling Tools ◽  
Output Performance ◽  
1D Model ◽  
The Impact

This paper presents a study on a small centrifugal impeller for microturbine application from a manufacturing perspective. The aim is to analyze the impact of geometric deviations on part performance using adequate performance modeling tools and statistical methods. A one-dimensional (1D) performance analysis tool was developed in-house derived from the meanline and two-zone modeling methods. The 1D model proved to be a simple and computationally inexpensive tool for having a quick performance analysis of the impeller using basic geometric information extracted from part drawings. For the sensitivity analysis, a total of eight input geometric parameters, including radii, tip-clearance, and blade angles, were varied individually within specific limits in the 1D tool for classifying their influence on the output performance. Since the 1D model is a simplified version of a much more complex three-dimensional (3D) model, a commercial computational fluid dynamics (CFD) tool was used to provide a comparison with the 1D model and scrutinize the effects of such deviations on the fluid behavior inside the impeller passage at a detailed level. For uncertainty quantification, Monte Carlo simulation was performed using the 1D model to assess the variability of overall impeller output performance to simultaneous random deviations in the input geometric parameters. The study is useful to evaluate the possibility of designing gas turbine parts for manufacturability and superior production cost-effectiveness.

scholarly journals Inner Workings of Aerodynamic Sweep

1997 ◽  
Author(s):  
A. R. Wadia ◽  
P. N. Szucs ◽  
D. W. Crall
Keyword(s):  
Boundary Layer ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Stall Margin ◽  
Design Speed ◽  
The Impact

The recent trend in using aerodynamic sweep to improve the performance of transonic blading has been one of the more significant technological evolutions for compression components in turbomachinery. This paper reports on the experimental and analytical assessment of the pay-off derived from both aft and forward sweep technology with respect to aerodynamic performance and stability. The single stage experimental investigation includes two aft-swept rotors with varying degree and type of aerodynamic sweep and one swept forward rotor. On a back-to-back test basis, the results are compared with an unswept rotor with excellent performance and adequate stall margin. Although designed to satisfy identical design speed requirements as the unswept rotor, the experimental results reveal significant variations in efficiency and stall margin with the swept rotors. At design speed, all the swept rotors demonstrated a peak stage efficiency level that was equal to that of the unswept rotor. However, the forward-swept rotor achieved the highest rotor-alone peak efficiency. At the same time, the forward-swept rotor demonstrated a significant improvement in stall margin relative to the already satisfactory level achieved by the unswept rotor. Increasing the level of aft sweep adversely affected the stall margin. A three-dimensional viscous flow analysis was used to assist in the interpretation of the data. The reduced shock/boundary layer interaction, resulting from reduced axial flow diffusion and less accumulation of centrifuged blade surface boundary layer at the up, was identified as the prime contributor to the enhanced performance with forward sweep. The impact of tip clearance on the performance and stability for one of the aft-swept rotors was also assessed.

The Impact of Forward Swept Rotors on Tip Clearance Flows in Subsonic Axial Compressors

2004 ◽  
Vol 126 (4) ◽  
pp. 445-454 ◽  
Author(s):  
G. Scott McNulty ◽  
John J. Decker ◽  
Brent F. Beacher ◽  
S. Arif Khalid
Keyword(s):  
Pressure Coefficient ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Flow Measurements ◽  
Stall Margin ◽  
Tip Clearance Flow ◽  
Axial Compressors ◽  
Flow Mechanisms ◽  
Cfd Analyses ◽  
The Impact

This paper presents an experimental and analytical study of the impact of forward swept rotors on tip-limited, low-speed, multistage axial compressors. Two different configurations were examined, one with strong tip-clearance flows and the other with more moderate levels. Evaluations were done at multiple rotor tip clearances to assess differences in clearance sensitivity. Compared to conventionally stacked radial rotors, the forward swept blades demonstrated improvements in stall margin, efficiency and clearance sensitivity. The benefits were more pronounced for the configuration with stronger tip-clearance flows. Detailed flow measurements and three-dimensional viscous CFD analyses were used to investigate the responsible flow mechanisms. Forward sweep causes a spanwise redistribution of flow toward the blade tip and reduces the tip loading in terms of static pressure coefficient. This results in reduced tip-clearance flow blockage, a shallower (more axial) vortex trajectory and a smaller region of reversed flow in the clearance gap.

scholarly journals A Navier-Stokes Analysis of the Effect of Tip Clearance on Compressor Stall Margin

1995 ◽  
Author(s):  
Robert P. Dring ◽  
William D. Sprout ◽  
Harris D. Weingold
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Stall Margin ◽  
Multi Stage ◽  
High Pressure Compressor ◽  
Practical Tool ◽  
The Impact ◽  
Pressure Compressor

A three-dimensional Navier-Stokes calculation was used to analyze the impact of rotor tip clearance on the stall margin of a multi-stage axial compressor. This paper presents a summary of: (1) a study of the sensitivity of the results to grid refinement, (2) an assessment of the calculation’s ability to predict stall margin when the stalling row was the first rotor in a multi-stage rig environment, (3) an analysis of the impact of including the effects of the downstream stator through body force effects on the upstream rotor, and (4) the ability of the calculation to predict the impact of tip clearance on stall margin through a calculation of the rear seven airfoil rows of an eleven stage high pressure compressor rig. The result of these studies was that a practical tool is available which can predict stall margin, and the impact of tip clearance, with reasonable accuracy.

Integration of 3D-CFD Component Simulation Into Overall Engine Performance Analysis for Engine Condition Monitoring Purposes

2018 ◽  
Author(s):  
C. Klein ◽  
F. Wolters ◽  
S. Reitenbach ◽  
D. Schönweitz
Keyword(s):  
Performance Analysis ◽  
Condition Monitoring ◽  
Guide Vane ◽  
Engine Performance ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Inlet Guide Vane ◽  
Cfd Model ◽  
The Impact ◽  
Engine Condition

For an efficient detection of single or multiple component damages, the knowledge of their impact on the overall engine performance is crucial. This knowledge can be either built up on measurement data, which is hardly available to non-manufacturers or –maintenance companies, or simulative approaches such as high fidelity component simulation combined with an overall cycle analysis. Due to a high degree of complexity and computational effort, overall system simulations of jet engines are typically performed as 0-dimensional thermodynamic performance analysis, based on scaled generic component maps. The approach of multi-fidelity simulation, allows the replacement of single components within the thermodynamic cycle model by higher-order simulations. Hence, the component behavior becomes directly linked to the actual hardware state of the component model. Hereby the assessment of component deteriorations in an overall system context is enabled and the resulting impact on the overall system can be quantified. The purpose of this study is to demonstrate the capabilities of multi fidelity simulation in the context of engine condition monitoring. For this purpose, a 0D-performance model of the IAE-V2527 engine is combined with a CFD model of the appropriate fan component. The CFD model comprises the rotor as well as the outlet guide vane of the bypass and the inlet guide vane of the core section. As an exemplarily component deterioration, the fan blade tip clearance is increased in multiple steps and the impact on the overall engine performance is assessed for typical engine operating conditions. The harmonization between both simulation levels is achieved by means of an improved map scaling approach using an optimization strategy leading to practicable simulation times.

Redesign of a Transonic Compressor Rotor by Means of a Three-Dimensional Inverse Design Method: A Parametric Study

2007 ◽  
Author(s):  
Duccio Bonaiuti ◽  
Abeetha Pitigala ◽  
Mehrdad Zangeneh ◽  
Yansheng Li
Keyword(s):  
Design Method ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Inverse Design ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Blade Loading ◽  
Inverse Design Method ◽  
The Impact

In the present paper, the redesign of a transonic rotor was performed by means of a three-dimensional viscous inverse design method. The inverse approach used in this work is one where the pressure loading, blade thickness distribution and stacking axis are specified and the camber surface is calculated accordingly. The design of transonic and supersonic axial compressors strongly relies on the ability to control the shock strength, location and structure. The use of an inverse design method allows one to act directly on aerodynamic parameters, like the blade loading, and provides an efficient tool to control the shock wave and its interaction with the boundary and secondary flows and with the tip clearance vortex. In the present study, the parametric investigation of the blade loading distribution was carried out. Few design parameters, with immediate physical meaning, were required to control the three-dimensional blade loading, and their impact on the design and off-design performance of the rotor was assessed by means of CFD calculations. Further investigations were then performed in order to study the impact on the rotor performance of the geometrical parameters (meridional channel and thickness distribution), which must be imposed in the design with the inverse method. As a result, it was possible to develop guidelines for the aerodynamic design of transonic rotors that can be exploited for similar design applications.

scholarly journals Reduction of Tip Clearance Losses Through 3-D Airfoil Designs

1996 ◽  
Author(s):  
J. Brent Staubach ◽  
Om P. Sharma ◽  
Gary M. Stetson
Keyword(s):  
Numerical Experiments ◽  
Three Dimensional ◽  
Full Scale ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Water Tunnel ◽  
Design Concepts ◽  
Overall Design ◽  
Physical Experiments ◽  
The Impact

Results are presented from a program, conducted to investigate the impact of spanwise stacking of turbine airfoil sections on tip clearance flows. Numerical as well as physical experiments were performed to demonstrate that these airfoils yielded about 40% reduction in tip clearance losses compared to those designed with a conventional approach. Three dimensional, steady Euler and Reynolds Averaged Navier Stokes (RANS) codes were used to execute the numerical experiments. Initial physical experiments were performed in a water tunnel by using linear cascades to validate the design concepts. The verification of the overall design concepts was executed in an uncooled full scale rotating rig.

Numerical Investigation of the Influence of the Tip Clearance on Wake Formation Inside a Radial Impeller

2003 ◽  
Author(s):  
Carsten Weiß ◽  
Daniel R. Grates ◽  
Hans Thermann ◽  
Reinhard Niehuis
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Trailing Edge ◽  
Flow Solver ◽  
Small Height ◽  
Wake Formation

The objective of the presented work is to investigate the influence of the tip clearance on the wake formation inside a radial impeller. The position and size of the wake region does not only depend on the clearance height, but also on the distribution of the clearance gap along the blade chord. In order to examine this influence, several calculations have been performed with a three dimensional Navier-Stokes flow solver on a centrifugal impeller, which was experimentally investigated in much detail at Aachen University. The original clearance gap was 0.7 mm at the leading edge and 0.48 mm at the trailing edge. These values were independently varied in the computations, such that different distributions of clearance heights could be chosen. The wake position of the smallest clearance height at the leading and trailing edge was closest to the pressure side. The calculations show, that a relatively large clearance height at the leading edge combined with a small height at the trailing edge move the wake further to the suction side, which corresponds very well with the experimental results. Reasons for that behavior are discussed in the paper.

Experimental and Numerical Investigations on a High Pressure Ratio Centrifugal Compressor

2005 ◽  
Author(s):  
Jae Ho Choi ◽  
Ok Suck Sung ◽  
Seung-Bae Chen ◽  
Jin Shik Lim
Keyword(s):  
Centrifugal Compressor ◽  
Performance Test ◽  
Pressure Ratio ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Design Flow ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Compressor Stage

An aerodynamic design, flow analysis and performance test of a pressure ratio 4:1 centrifugal compressor are presented in this paper. The compressor is made up of a centrifugal impeller, a two-stage diffuser consisted of radial and axial types. The impeller has a 45 degree backswept angle and the design running tip clearance is 5% of impeller exit height. Two types of diffusers are designed for this compressor. Three-dimensional numerical analysis is performed to analyze the flows in the impeller, diffuser and deswirler considering the impeller tip clearance. A test module and rig facilities for the compressor stage performance test are designed and fabricated. The overall compressor stage performances as well as the static pressure fields on the impeller and diffuser are measured. Two diffusers of wedge and airfoil types are tested with an impeller. The calculation and test results show the airfoil diffuser has the better aerodynamic characteristics than those of wedge diffuser in the studied models.

scholarly journals Effect of Area Ratio on the Performance of a 5.5:1 Pressure Ratio Centrifugal Impeller

1987 ◽  
Vol 109 (1) ◽  
pp. 10-19 ◽  
Author(s):  
L. F. Schumann ◽  
D. A. Clark ◽  
J. R. Wood
Keyword(s):  
Pressure Ratio ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Computer Code ◽  
Area Ratio ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Recovery Coefficient ◽  
Flow Angle ◽  
Design Point

A centrifugal impeller which was initially designed for a pressure ratio of approximately 5.5 and a mass flow rate of 0.959 kg/s was tested with a vaneless diffuser for a range of design point impeller area ratios from 2.322 to 2.945. The impeller area ratio was changed by successively cutting back the impeller exit axial width from an initial value of 7.57 mm to a final value of 5.97 mm. In all, four separate area ratios were tested. For each area ratio a series of impeller exit axial clearances was also tested. Test results are based on impeller exit surveys of total pressure, total temperature, and flow angle at a radius 1.115 times the impeller exit radius. Results of the tests at design speed, peak efficiency, and an exit tip clearance of 8 percent of exit blade height show that the impeller equivalent pressure recovery coefficient peaked at a design point area ratio of approximately 2.748 while the impeller aerodynamic efficiency peaked at a lower value of area ratio of approximately 2.55. The variation of impeller efficiency with clearance showed expected trends with a loss of approximately 0.4 points in impeller efficiency for each percent increase in exit axial tip clearance for all impellers tested. The data also indicated that the impeller would probably separate at design area ratios greater than 2.748. An analysis was performed with a quasi-three-dimensional inviscid computer code which confirmed that a minimum velocity ratio was attained near this area ratio thus indicating separation. These data can be used to verify impeller flow models which attempt to account for very high diffusion and possible separation.

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