New Optimization Criteria for the Design of Three-Dimensional Bladings Applied to Compound Lean Nozzles of an Axial Turbine

2004 ◽  
Author(s):  
Franz Wingelhofer ◽  
Hermann Haselbacher
Keyword(s):  
Performance Improvement ◽  
High Performance ◽  
Three Dimensional ◽  
Objective Functions ◽  
Blade Row ◽  
Axial Turbines ◽  
Two Parameters ◽  
Stage Efficiency ◽  
Dimensional Optimization

The performance of axial turbines can be improved by the application of three-dimensionally shaped bladings. The performance improvement by three-dimensionally shaped bladings is perceptible only within a stage, leading to a time-accurate three-dimensional optimization. The paper describes two objective functions that, if applied to an isolated turbine blade row, may help to reduce the range of feasible geometries. The quality of the objective functions is tested in a parametric study, in which the stator row geometry is parameterized by only one parameter. The stage efficiency, obtained by evaluation of the time-accurate flows through turbine stages with different stator rows, is used as criterion. An optimization of compound lean nozzles parameterized by two parameters is performed with the more accurate objective function resulting in high performance compound lean nozzles.

Research on Fabricating Technology of Three Dimensional Integrated Braided Composite I Beam

2010 ◽  
Vol 136 ◽  
pp. 59-63 ◽  
Author(s):  
X.Y. Pei ◽  
Jia Lu Li
Keyword(s):  
Cross Section ◽  
High Performance ◽  
Research Result ◽  
Three Dimensional ◽  
Void Content ◽  
Braided Composites ◽  
Braided Composite ◽  
Transfer Molding ◽  
3D Braided Composites

In this paper the fabricating technology of three dimensional (3D) integrated braided composite I beam is researched, including: braiding technology of 3D braided I beam preform, the orientation of fiber-tow in the I beam preform, the optimizing of process parameters of resin transfer molding (RTM) for 3D braided composite I beam, and the design of mould for consolidation of composite I beam. The quality of 3D braided composites is good analyzed by ultrasonic A-scan, void content calculation and microscope observation. The research result will provide a good way for designing and fabricating high performance 3D integrated braided composite components with irregular cross section.

scholarly journals A flash-based thermal simulation of scanning paths in LPBF additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kamel Ettaieb ◽  
Sylvain Lavernhe ◽  
Christophe Tournier
Keyword(s):  
High Performance ◽  
Laser Scanning ◽  
Thermal Field ◽  
Computational Cost ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Content Type ◽  
Proposed Model ◽  
Scanning Path

Purpose This paper aims to propose an analytical thermal three-dimensional model that allows an efficient evaluation of the thermal effect of the laser-scanning path. During manufacturing by laser powder bed fusion (LPBF), the laser-scanning path influences the thermo-mechanical behavior of parts. Therefore, it is necessary to validate the path generation considering the thermal behavior induced by this process to improve the quality of parts. Design/methodology/approach The proposed model, based on the effect of successive thermal flashes along the scanning path, is calibrated and validated by comparison with thermal results obtained by FEM software and experimental measurements. A numerical investigation is performed to compare different scanning path strategies on the Ti6Al4V material with different stimulation parameters. Findings The simulation results confirm the effectiveness of the approach to simulate the thermal field to validate the scanning strategy. It suggests a change in the scale of simulation thanks to high-performance computing resources. Originality/value The flash-based approach is designed to ensure the quality of the simulated thermal field while minimizing the computational cost.

ALSTOM-CPS San Antonio Retrofit of JK Spruce Unit 1 HP-IP Turbine: An Example of an Advanced Steam Turbine Upgrade for Improved Performance by a Non-OEM Supplier

2005 ◽  
Author(s):  
Simon Hogg ◽  
Donald Stephen
Keyword(s):  
Performance Improvement ◽  
High Performance ◽  
Three Dimensional ◽  
Prediction Method ◽  
Variation Method ◽  
Performance Guarantees ◽  
Steam Admission ◽  
Drop Tests ◽  
Improved Performance ◽  
Over Time

This paper describes in detail ALSTOM’s steam path upgrade of JK Spruce Unit 1 GE ‘G2’ HP-IP turbine cylinder. The retrofit features high performance impulse technology three dimensional blade designs for short height turbine stages. Performance improvement was achieved through improved aerodynamic design and increased stage count in the HP expansion (the number of stages in the IP remained unchanged in order to maintain the steam conditions in an extraction part-way down the steam path). The unit was also converted from partial arc to full arc steam admission during the retrofit which resulted in additional performance improvement at full load conditions. Performance guarantees for the retrofit were given in the form of absolute values for HP and IP cylinder adiabatic efficiency and a guarantee on absolute post-retrofit output power. The guarantee levels were based on in-house performance prediction method for turbine cylinders employing the Company’s low reaction technology blading. The code is based on the method first described by Craig and Cox [1], which has been continuously updated and developed to correctly account for advances in the company’s steam path technology over time. The guarantee for the HP cylinder efficiency (excluding the effect of inlet valve pressure drop) was 93.0%, the IP cylinder was guaranteed to achieve an efficiency of 92.8% excluding valves. The retrofit performance achieved was verified by enthalpy drop tests on the HP and IP expansions and the guaranteed performance levels were achieved in both cases. The centre-gland leakage was also measured as part of the performance guarantee testing. A novel method using the centre-gland blowdown pipe was employed, as an alternative to the temperature variation method. This alternative approach is described in the paper. The retrofit has now been in operation for a period of approximately two years and following the initial guarantee testing, additional performance tests have taken place at various points during this period. The data allows any degradation in the performance of the retrofit cylinder over time to be assessed. This is also discussed in the paper.

Radial Inflow Into the Downstream Cavity of a Compressor Stator Well

2000 ◽  
Author(s):  
R. M. Scott ◽  
P. R. N. Childs ◽  
N. J. Hills ◽  
J. A. Millward
Keyword(s):  
Pressure Gradient ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Labyrinth Seal ◽  
Cfd Models ◽  
Wide Range ◽  
Blade Row ◽  
Axial Turbines ◽  
Radial Outflow

The subject of the interaction between the mainstream annulus flow and seal flows is now receiving increased attention as a result of concerted attempts to further improve compressor performance. In an axial compressor the use of a shroud on a stator blade row necessitates a trench and results in two such regions of interaction at the upstream and downstream stator well cavities with flow limited by a labyrinth seal. The upstream stator well cavity, with its superposed radial outflow, has received some attention and possess similarities with the cavity downstream of nozzle guide vanes in axial turbines, which have received considerable interest. The downstream compressor stator well cavity has, however, been less extensively studied. Here the flow is dominated by inflow into the cavity. This inflow is driven by the pressure gradient across the blade row and hence the pressure gradient between the upstream and downstream cavities. This paper presents preliminary pressure measurements from a high-speed two-stage research compressor. The experimental results are compared with two and three-dimensional CFD models. In order to gain confidence with CFD for compressor stator wells, the case of inflow into a rotor-stator disc wheelspace has been revisited; validating a commercial code, Fluent, for a wide range of flow conditions. This code has then been used to predict the detailed flow structure for the conditions in the experimental research compressor.

Unsteady Transport Mechanisms in an Axial Turbine

2000 ◽  
Vol 122 (4) ◽  
pp. 604-612 ◽  
Author(s):  
Claudia Casciaro ◽  
Martin Treiber ◽  
Michael Sell
Keyword(s):  
Fluid Transport ◽  
Three Dimensional ◽  
Leading Edge ◽  
Dimensional Case ◽  
Navier Stokes ◽  
Mixing Processes ◽  
Commercial Code ◽  
Wake Interaction ◽  
Blade Row ◽  
Axial Turbines

A numerical analysis using a commercial unsteady Navier–Stokes solver has been performed on a pin/blade configuration, in order to assess the efficacy of a commercial code in calculating time-periodic interactions and to gain a better understanding of the unsteady flow physics in axial turbines. Two cases have been investigated, with the pin positioned at 25 and 50 percent of true chord ahead of the leading edge. Both configurations have been computed both two and three dimensionally. The two-dimensional case was used to examine the influence of numerical parameters, such as mesh, time, and space discretization. The three-dimensional case allowed insight into the complete flow field including the wake influence on the secondary flow and mixing processes of the blade row. The basic mechanisms of the wake–blade interaction proved, as expected, to be the same for both pin positions. Yet, as the closest pin wake interaction with the blade field was much stronger, its features have helped to identify the respective roles of wake fluid transport and blade potential field for both cases. The latter effect, noticeably strong with the thick leading edge blade form presented in this study, has often been neglected, and this study helps shed new light on this phenomenon. The code used had been validated in previous work for pin-free steady flow within the same blade row and the new time-dependent case has served to confirm the code range and limitations. [S0889-504X(00)02104-8]

Real-Time Full Motion Stereo Microscopy Over Internet

1999 ◽  
Vol 5 (S2) ◽  
pp. 368-369
Author(s):  
Gary N. Case ◽  
Mladen A. Vouk ◽  
John M. Mackenzie
Keyword(s):  
Quality Of Service ◽  
Real World ◽  
High Performance ◽  
Video Transmission ◽  
Three Dimensional ◽  
High Definition ◽  
The Real ◽  
Remote Imaging ◽  
Full Screen

One of the problems with remote imaging which purports to represent the real world (Tele-presence) is that the images are two-dimensional and the “real” world is three dimensional. When viewing many objects, the lack of depth perceptiorican be a serious deficiency. For example, one would want a micro-surgeon to have a good idea how deep to cut into tissue during a tele-presence operation. There is a wealth of three dimensional information in light, SEM, AFM, confocal, and computer reconstructed or simulated objects. To transfer that information faithfully over the networks using broadcast quality high definition video transmission technologies such as MPEG2 may require as much as 20 Mbps per channel. Furthermore, stereo imaging is particularly sensitive to any phase delays and jitter between the two eye channels. Control of these parameters requires advance quality of service features that current internet does not provide, but that may be available on high-performance intranets. All this may present a problem for routine use of the stereo facility .The next generation of Internet, however, will be able to routinely provision much higher bandwidth and other quality of service, in general through protocols that will allow for not only full screen full resolution television but also the use of two channels (left and right) that can stay in fairly close synchrony.

Applications of Scanning Microscopy in Biomedical Research

1968 ◽  
Vol 26 ◽  
pp. 354-355
Author(s):  
T. L. Hayes
Keyword(s):  
Information Content ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Dental Enamel ◽  
Resolving Power ◽  
Whole Mount ◽  
Two Parameters ◽  
Content Information ◽  
Sectioned Tissue

Biomedical applications of the scanning electron microscope (SEM) have increased in number quite rapidly over the last several years. Studies have been made of cells, whole mount tissue, sectioned tissue, particles, human chromosomes, microorganisms, dental enamel and skeletal material. Many of the advantages of using this instrument for such investigations come from its ability to produce images that are high in information content. Information about the chemical make-up of the specimen, its electrical properties and its three dimensional architecture all may be represented in such images. Since the biological system is distinctive in its chemistry and often spatially scaled to the resolving power of the SEM, these images are particularly useful in biomedical research.In any form of microscopy there are two parameters that together determine the usefulness of the image. One parameter is the size of the volume being studied or resolving power of the instrument and the other is the amount of information about this volume that is displayed in the image. Both parameters are important in describing the performance of a microscope. The light microscope image, for example, is rich in information content (chemical, spatial, living specimen, etc.) but is very limited in resolving power.

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