Aerodynamic design of 50 per cent reaction steam turbines

1999 ◽  
Vol 213 (1) ◽  
pp. 1-25 ◽  
Author(s):  
S Havakechian ◽  
R Greim
Keyword(s):  
High Efficiency ◽  
Performance Enhancement ◽  
Three Dimensional ◽  
Deep Understanding ◽  
Design Tools ◽  
Steam Turbines ◽  
Aerodynamic Design ◽  
Aerodynamic Properties ◽  
Flow Phenomena

On the basis of their inherent favourable aerodynamic properties coupled with past progress, 50 per cent reaction stages already achieve a high efficiency level. Developments aimed at further performance enhancement entail employment of advanced design features that require a deep understanding of the flow phenomena involved and their interactions. In addition, substantial on-going efforts are needed to improve the quality of the design tools. This paper focuses on the key design issues, including advanced quasi-three-dimensional and three-dimensional design aspects. It further describes developments by the authors' company during the last decade for the design of modern reaction blading and establishment of state-of-the-art design tools.

scholarly journals Flow-Induced Vibration on the Control Valve with a Different Concave Plug Shape Using FSI Simulation

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Akram Zeid ◽  
Mohamed Shouman
Keyword(s):  
High Efficiency ◽  
Complex Structure ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
Control Valve ◽  
Low Noise ◽  
Flow Induced Vibration ◽  
Nonlinear Characteristics ◽  
Flow Phenomena

Control valves have always been recognised as being among the most crucial control equipment, commonly utilised in versatile engineering applications. Hence, the need has arisen to identify the flow characteristics inside the valve, together with the incurred vibration induced as a result of the flow passing through the valve. Thanks to the tangible and fast progress made in the field of the flow simulation and numerical techniques, it has become possible to better observe the behavior of the flow passing inside a valve with view to examining its performance. Hence, the paper at hand is mainly concerned with introducing the modeling and simulation of a control valve. On the contrary, the flow system in a control valve is marked by a complex structure and nonlinear characteristics. The reasons for those qualities could be attributed to its construction as well as the fluid flow phenomena associated with it. It is especially for the sake of investigating and observing the flow characteristics, pertaining to a control valve equipped with different concave plug shapes and different openings, that the three-dimensional FSI simulation is conducted. In addition, it would be possible to make use of the obtained results relating to the three-dimensional analysis to achieve low noise and high efficiency improvement. Furthermore, all results will be validated on experimental grounds.

Numerical Investigation of Three-Dimensional Wet Steam Flows in an Exhaust Diffuser With Non-Uniform Inlet Flows From the Turbine Stages in a Steam Turbine

2012 ◽  
Author(s):  
Tadashi Tanuma ◽  
Yasuhiro Sasao ◽  
Satoru Yamamoto ◽  
Yoshiki Niizeki ◽  
Naoki Shibukawa ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Numerical Investigation ◽  
Evaluation Method ◽  
High Efficiency ◽  
Mechanical Design ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Steam Turbines ◽  
Wet Steam ◽  
Low Pressure Turbine

The purpose of this paper is to present a numerical evaluation method for the aerodynamic design and development of high-efficiency exhaust diffusers in steam turbines, as well as to present the comparison between the numerical results and measured data in an actual real scale development steam turbine. This paper presents numerical investigation of three-dimensional wet steam flows in a down-flow-type exhaust diffuser that has non-uniform inlet flows from a typical last turbine stage. This stage has long transonic blades designed using recent aerodynamic and mechanical design technologies, including superimposed leakages and blade wakes from several upstream low pressure turbine stages. The present numerical flow analysis showed detail three-dimensional flow structures considering circumferential flow distributions caused by the down-flow exhaust hood geometry and the swirl velocity component from the last stage blades, including flow separations in the exhaust diffuser. The results were compared with experimental data measured in an actual development steam turbine. Consequently, the proposed aerodynamic evaluation method was proved to be sufficiently accurate for steam turbine exhaust diffuser aerodynamic designs.

3-D FEM Simulation of Laser Peening Straightening for Shaft Straightness

2018 ◽  
Vol 765 ◽  
pp. 243-248
Author(s):  
Bo Yong Su ◽  
Yong Kang Zhang ◽  
Gui Fang Sun ◽  
Pei Xu ◽  
Ran Zhu ◽  
...  
Keyword(s):  
Pulse Duration ◽  
High Efficiency ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Finite Model ◽  
Laser Peening ◽  
Mechanical Method ◽  
Important Indicator ◽  
Shaft Surface

The straightness is an important indicator in measuring the quality of shaft parts. Laser peening straightening (LPS) is a new mechanical method to straight the shaft through inducing residual compressive stress into the shaft surface. Compared with the traditional method, the process of laser peening correction is high efficiency and can be controlled precisely. In the present work, the mechanism of laser peening straightening for shaft straightness is revealed and a three-dimensional finite model is developed to investigate the effects of laser parameters for shaft straightness correction. The results show that the peak pressure and pulse duration should be more than 4 GPa and 8 ns when laser peening straightening is used to correct the shaft straightness. The straightening amount increases with laser power density, laser pulse duration, multiple laser peening. The maximum correction amount for shaft straightness with LPS is no more than 0.01mm.

Performance of Axial-Flow Turbines

1948 ◽  
Vol 159 (1) ◽  
pp. 230-244 ◽  
Author(s):  
D. G. Ainley
Keyword(s):  
Gas Turbine ◽  
Experimental Work ◽  
Gas Flow ◽  
High Efficiency ◽  
Gas Turbine Engine ◽  
Steam Turbines ◽  
Aerodynamic Design ◽  
Turbine Engine ◽  
Turbine Performance ◽  
Economic Operation

The advent of the gas-turbine engine, with its absolute dependence on high component efficiencies for reasonable economic operation, and the necessity for new materials which will withstand high stresses at much greater temperatures than encountered on steam turbines, has led engineers to review the design of turbines closely both from an aerodynamic and a mechanical standpoint: there is still a great deal to be learnt. Reeman† has outlined the present mathematical approach to the design of turbines and surveyed very comprehensively the mechanical problems that are involved. This paper is intended to indicate the manner in which the aerodynamic design of a turbine has developed from that of its steam predecessor and, in particular, surveys some recent experimental work relating to turbine performance. The general aims of the experimental work are to explore the gas-flow processes within a turbine stage, to determine the associate aerodynamic efficiencies, and to gain some understanding of the limitations imposed upon the aerodynamic design of a stage by the necessity for the high efficiency which is required for economic operation of a gas-turbine engine. The data that have so far come to light, though incomplete, illustrate the general overall characteristics of high- and low-reaction turbines, and also the effect that high Mach number or low Reynolds number may have on turbine performance. To conclude the paper, a brief description of the technique adopted for adequate full-scale testing of turbines is presented. This covers the essential points of, power absorption, instrumentation, and safety precaution. The effects of errors in measurements are also discussed.

scholarly journals An Efficient Mesh Generation Method for Fractured Network System Based on Dynamic Grid Deformation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shuli Sun ◽  
Jie Sui ◽  
Bin Chen ◽  
Mingwu Yuan
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Network System ◽  
Computational Domain ◽  
Topological Transformation ◽  
Grid Deformation ◽  
Insertion Algorithm ◽  
Fractured Network ◽  
Deformation Approach

Meshing quality of the discrete model influences the accuracy, convergence, and efficiency of the solution for fractured network system in geological problem. However, modeling and meshing of such a fractured network system are usually tedious and difficult due to geometric complexity of the computational domain induced by existence and extension of fractures. The traditional meshing method to deal with fractures usually involves boundary recovery operation based on topological transformation, which relies on many complicated techniques and skills. This paper presents an alternative and efficient approach for meshing fractured network system. The method firstly presets points on fractures and then performs Delaunay triangulation to obtain preliminary mesh by point-by-point centroid insertion algorithm. Then the fractures are exactly recovered by local correction with revised dynamic grid deformation approach. Smoothing algorithm is finally applied to improve the quality of mesh. The proposed approach is efficient, easy to implement, and applicable to the cases of initial existing fractures and extension of fractures. The method is successfully applied to modeling of two- and three-dimensional discrete fractured network (DFN) system in geological problems to demonstrate its effectiveness and high efficiency.

Numerical Investigation of Self-Driven Fan Performance With Tip-Jet

2017 ◽  
Author(s):  
Lei Li ◽  
GuoPing Huang ◽  
Jie Chen ◽  
JinChun Wang
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Suction Surface ◽  
Navier Stokes Equations ◽  
Momentum Coefficient ◽  
Aerodynamic Properties ◽  
Flow Phenomena ◽  
Cfd Method

Tip-jet rotor system has unique potential value in the area of vertical take-off and landing (VTOL) or short take-off and landing (STOL) concept aircraft. The main objective of the current work is to investigate the aerodynamic properties of a self-driven fan with tip-jet (SDF_TJ) in hover by numerical experiments. In order to obtain the detailed flow phenomena of SDF_TJ, CFD method is performed, which is conducted by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. For the purpose of investigation, the analysis of SDF_TJ performances with different nozzle configurations have been carried out. Current results indicate the conformal tip-jet not only provide the reaction torque, but also augment the fan lift via entraining the main flow above the suction surface of blade. The rotation speed of fan is mainly determined by bleed air parameters and nozzle area, so as to torque self-balance. The total torque produced by jets contains rotor required torque and penalty torque induced by Coriolis force. The blade lift coefficient and the ratio with jet momentum coefficient are influenced by the distance from the nozzle downstream edge to blade trailing. As the lift of SDF_TJ is larger than the thrust generated by jets alone, which could benefit the take-off and landing capability of VTOL concept aircraft.

Aerodynamic Design and Prototype Testing of a New Line of High Efficiency, High Pressure, 50% Reaction Steam Turbines

2007 ◽  
Author(s):  
Joseph A. Cotroneo ◽  
Tara A. Cole ◽  
Douglas C. Hofer
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Volume Flow ◽  
Steam Turbines ◽  
Aerodynamic Design ◽  
Flow Paths ◽  
Low Volume

The aerodynamic design and prototype performance testing of a new line of high efficiency, high pressure (HP), 50% reaction steam turbines is described in some detail. Three designs were carried out that can be used in a repeating stage fashion to form high efficiency steam paths. The designs were performed employing a blade master concept. The masters can be aerodynamically scaled and cut to cover a wide range of applications while maintaining vector diagram integrity. Three equivalent prototype flow paths, one each for Gen 0, 1 and 2, masters were designed and tested in a Steam Turbine Test Vehicle (STTV). These prototype designs are representative of high pressure steam turbines for combined cycle power plants. Design of experiments is used to optimize the flow path, stage counts and diameters for production designs taking into account multidisciplinary design constraints. Four such Gen 1 steam path designs have been executed to date as part of a structured series of combined cycle power plants. [1-5] There are two A14 HEAT* (High Efficiency Advanced Technology) steam turbine HP flow paths for GE’s 107FA combined cycle power plants and two A15 HEAT HP flow paths for the 109FB. The larger of the A14 HEAT steam turbine HP’s has recently been performance tested at a customer site demonstrating world class efficiency levels of over 90% for this low volume flow combined cycle turbine [1]. HP volume flows are likely to drop even lower in the future with the need to go to higher steam inlet pressure for combined cycle efficiency improvements so steam path designs with high efficiency at low volume flow will be increasingly important.

Scanning Electron Microscopy in Hybrid Microelectronics

1976 ◽  
Vol 34 ◽  
pp. 456-457
Author(s):  
S. Khadpe ◽  
R. Faryniak
Keyword(s):  
Integrated Circuits ◽  
Thick Film ◽  
Integrated Circuit ◽  
Failure Modes ◽  
Three Dimensional ◽  
Circuit Components ◽  
Hybrid Microcircuit ◽  
Electrical Connections ◽  
Scanning Electron

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

Sign in / Sign up

Export Citation Format

Share Document