Applying CAx Technology for the Design of a Gas Turbine Exhaust

Author(s):  
L. Itter ◽  
M. Cagna ◽  
A. Wiedermann ◽  
M. Boehle

Today’s market for gas turbines is getting bigger since there is a huge demand for power generation and mechanical drive applications. To meet the market requirements gas turbine components have to be very efficient to play a leading role. In order to accelerate component improvement the introduction of integrated CAx Technology is a key to achieve a less time-consuming and therefore cheaper design. This paper will describe a procedure which can be used to design an exhaust system for gas turbines with hot-end drive. It shows how to combine various technologies like CAD and CFD and make them work together rapidly. Firstly a 1D design is done and compared with a performance chart of conventional use. Then, a 2D parametric study of a 90 degree bend will be performed by the combination of a CAD-system and a CFD-solver. Thirdly a full 3D-simulation of the entire exhaust will be performed with a calibrated solver. Different complex geometry modifications are applied and their influence on the performance of the exhaust will be discussed.

1990 ◽  
Vol 112 (1) ◽  
pp. 80-85
Author(s):  
F. Fleischer ◽  
C. Koerner ◽  
J. Mann

Following repeated cases of damage caused to exhaust silencers located directly beyond gas turbine diffusers, this paper reports on investigations carried out to determine possible remedies. In all instances, an uneven exhaust gas flow distribution was found. The company’s innovative approach to the problem involved constructing a scale model of a complete gas turbine exhaust system and using it for flow simulation purposes. It was established for the first time that, subject to certain conditions, the results of tests conducted on a model can be applied to the actual turbine exhaust system. It is shown that when an unfavorable duct arrangement might produce an uneven exhaust flow, scale models are useful in the development of suitable flow-distributing devices.


Author(s):  
P. F. Martinuzzi

The combination of a gas turbine with a steam turbine driven by steam produced in a generator heated by the gas-turbine exhaust is studied. The field of application of such a gas-steam power plant is examined, as well as the best operational characteristics of the combination. The special features of closed-cycle gas turbines, particularly of the type used in conjunction with gas-cooled, high-temperature nuclear reactors, are shown to give considerable advantages when combined with a steam turbine.


Author(s):  
Friedrich Fleischer ◽  
Christian Koerner ◽  
Juergen Mann

Following repeated cases of damage caused to exhaust silencers located directly beyond gas turbine diffusers, this paper reports on investigations carried out to determine possible remedies. In all instances, an uneven exhaust gas flow distribution was found to be present. The company’s innovative approach to the problem involved constructing a scale model of a complete gas turbine exhaust system and using it for flow simulation purposes. It was established for the first time that, subject to certain conditions, the results of tests conducted on a model can be applied to the actual turbine exhaust system. It is shown that when an unfavourable duct arrangement might produce an uneven exhaust flow, scale models are useful in the development of suitable flow-distributing devices.


Author(s):  
Jie Gao ◽  
Feng Lin ◽  
Xiying Niu ◽  
Qun Zheng ◽  
Guoqiang Yue ◽  
...  

The marine gas turbine exhaust volute is an important component that connects a power turbine and an exhaust system, and it is of great importance to the overall performance of the gas turbine. Gases exhausted from the power turbine are expanded and deflected 90 degrees in the exhaust volute, and then discharge radially into the exhaust system. The flows in the power turbine and the nonaxisymmetric exhaust volute are closely coupled and inherently unsteady. The flow interactions between the power turbine and the exhaust volute have a significant influence on the shrouded rotor blade aerodynamic forces. However, the interactions have not been taken into account properly in current power turbine design approaches. The present study aims to investigate the flow interactions between the last stage of a shrouded power turbine and the nonaxisymmetric exhaust volute with struts. Special attention is given to the coupled aerodynamics and pressure response studies. This work was carried out using coupled computational fluid dynamics (CFD) simulations with the computational domain including a stator vane, 76 shrouded rotor blades, 9 struts and an exhaust volute. Three-dimensional (3D) unsteady and steady Reynolds-averaged Navier-Stokes (RANS) solutions in conjunction with a Spalart-Allmaras turbulence model are utilized to investigate the aerodynamic characteristics of shrouded rotors and an exhaust volute using a commercial CFD software ANSYS Fluent 14.0. The asymmetric flow fields are analyzed in detail; as are the unsteady pressures on the shrouded rotor blade. In addition, the unsteady total pressures at the volute outlet is also analyzed without consideration of the upstream turbine effects. Results show that the flows in the nonaxisymmetric exhaust volute are inherently unsteady; for the studied turbine-exhaust configuration the nonaxisymmetric back-pressure induced by the downstream volute leads to the local flow varying for each shrouded blade and low frequency fluctuations in the blade force. Detailed results from this investigation are presented and discussed in this paper.


Author(s):  
Wolfgang Kappis ◽  
Stefan Florjancic ◽  
Uwe Ruedel

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.


1974 ◽  
Author(s):  
Marv Weiss

A unique method for silencing heavy-duty gas turbines is described. The Switchback exhaust silencer which utilizes no conventional parallel baffles has at operating conditions measured attenuation values from 20 dB at 63 Hz to 45 dB at higher frequencies. Acoustic testing and analyses at both ambient and operating conditions are discussed.


1998 ◽  
Vol 120 (07) ◽  
pp. 72-73 ◽  
Author(s):  
Michael Valent

This article reviews that twenty-first century passengers on the Royal Caribbean International and Celebrity Cruises are set to make history in style. Up to six of Royal Caribbean’s Voyager- and Millennium-class vessels will be the first cruise ships ever powered by General Electric’s gas turbines. In addition to reducing engine-room noise and vibration and cutting emissions, this propulsion system—a departure from the traditional diesel engine—will make it possible for ships to set sail with a reduced maintenance crew and smaller parts inventory. Royal Caribbean International currently operates a fleet of 12 ships. In the Royal Caribbean application, the GE gas turbine will be used to drive generators that will provide electricity to propeller motors. The steam turbine will recover heat from the gas turbine exhaust for other uses. This combined gas turbine and steam turbine integrated electric drive system represents a departure from diesel engines in more than one respect.


Procedia CIRP ◽  
2019 ◽  
Vol 83 ◽  
pp. 630-635 ◽  
Author(s):  
Fei Zhao ◽  
Liang Chen ◽  
Tangbin Xia ◽  
Zikun Ye ◽  
Yu Zheng

Author(s):  
Lothar Bachmann ◽  
W. Fred Koch

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.


Author(s):  
Fangyuan Zhong ◽  
Yu Dai

On the basis of scale model tests in two different dimensions of marine gas turbine exhaust system with infrared signature suppression device, and in the light of similarity analysis and simplified numerical calculation, this paper discusses the effects of scale factor on the flow (flow resistance), temperature (of air-flow and tube wall), and infrared radiant (of exhaust plumes and exhaust uptake inner wall) fields of the exhaust system, and accordingly estimates the corresponding parameters of real ship exhaust systems as well as presents the magnitude of scale factor impacts and the recommended values for selecting the scale factor.


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