Measurements of the Four-Quadrant Characteristics on a Multi-Stage Turbine

1980 ◽  
Vol 102 (2) ◽  
pp. 316-321 ◽  
Author(s):  
K. Bammert ◽  
P. Zehner
Keyword(s):  
Gas Turbines ◽  
Single Stage ◽  
Operation Conditions ◽  
Multi Stage ◽  
Performance Curves ◽  
Stage Performance ◽  
The Individual ◽  
Four Quadrant ◽  
Operating Points ◽  
Energy Plants

With turbines, operation conditions far from the design range are possible. With gas turbines, in nuclear and solar energy plants in the case of a fault, flow in reverse directions may even occur. For extreme operations insufficient knowledge was available, so measurements were carried out at first on a single-stage turbine and then on a seven-stage turbine, with both the mass flow and the rotor speed systematically varied in the positive (normal direction) and negative ranges (four-quadrant characteristics). The measurement on the seven-stage turbine basically tally with the single-stage measurements. Stage performance curves can be approximately calculated also for four quadrants from the cascade characteristics of the middle section. The calculated curves are compared to the results of the single-stage measurements. During operation far from the design point, the individual stages of a multi-stage turbine work at a wide variety of operating points, so the characteristics of such a turbine have to be determined by the superimposition of the corresponding stage performance curves on each other.

Towards Visualisation of Capacity, Bearing Thrust Load and Reaction Variation With Aerofoil Skew in a Gas Turbine

2019 ◽  
Author(s):  
Karthik Srinivasan ◽  
Soumyik K. Bhaumik ◽  
Lakshmanan Valliappan
Keyword(s):  
Gas Turbines ◽  
System Level ◽  
Skew Angle ◽  
Small Deviations ◽  
Pressure Drops ◽  
Performance Targets ◽  
Multi Stage ◽  
The Individual ◽  
The Impact ◽  
Thrust Load

Abstract The requirements in the design of aerofoils for gas turbines are not limited to only meeting the aerothermal performance. A typical scenario for a turbine is to understand the impact of aerofoil skew on capacity, reaction and bearing thrust load. A means to achieve the target capacity could be by skewing the aerofoil. This, however, changes the stage reaction which in turn impacts the bearing thrust load. In the case of a multi stage turbine, the work split between the stages impacts the ratio of pressure drops and hence the contribution of the individual aerofoil rows to the overall capacity and bearing thrust load variation. This paper deals with a generic approach to visualise the variation of capacity and bearing thrust load with aerofoil skew for a stage of interest along with the Constraints that could be potentially imposed on the stage. This methodology provides a useful mapping between parameters which are directly under the aerodynamicist’s control (i.e. aerofoil skew) to module- and system-level behaviours (i.e. capacity, bearing thrust load). It thereby allows informed choices to be made throughout the design process which deliver the turbine aerodynamic performance targets whilst respecting wider system-level constraints. Suitable optimisation within this design space will yield a design that is fundamentally robust to small deviations in skew angle. Additionally, qualitative variation of the gas path static pressure and reaction based on aerofoil skews are explained pictorially to facilitate the understanding.

Stability Analysis of Turbomachinery From the Viewpoint of Seal

1991 ◽  
Author(s):  
T. Iwatsubo ◽  
B. C. Sheng
Keyword(s):  
Stability Analysis ◽  
Working Conditions ◽  
Single Stage ◽  
Fluid Element ◽  
Individual Contribution ◽  
Rotating Fluid ◽  
Dynamic Interactions ◽  
Multi Stage ◽  
The Stability ◽  
The Individual

Abstract The stability of the typical rotating fluid machineries such as the single-stage and multi-stage pumps which consist of impellers, bearings and noncontacting seals is evaluated from the viewpoint of seals. The individual contribution of the impeller, bearing as well as seal to the stability, and the dynamic interactions of these fluid elements are investigated. In the investigation, some types of bearings, and seals such as annular smooth seals, parallel grooved seals and damper seals are compared to seek the better ones for the rotor stability. The effect of working conditions on the stability is also investigated. The results show that the rotor stability is strongly affected by the characteristics of these fluid elements, and the stability can be improved by changing the unstable fluid element.

Conjugate Heat Transfer and Film Cooling of a Multi-Stage Cooling Scheme

2008 ◽  
Author(s):  
M. Ghorab ◽  
S. I. Kim ◽  
I. Hassan
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Density Ratio ◽  
Design Parameters ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Multi Stage ◽  
Internal Gap

Cooling techniques play a key role in improving efficiency and power output of modern gas turbines. The conjugate technique of film and impingement cooling schemes is considered in this study. The Multi-Stage Cooling Scheme (MSCS) involves coolant passing from inside to outside turbine blade through two stages. The first stage; the coolant passes through first hole to internal gap where the impinging jet cools the external layer of the blade. Finally, the coolant passes through the internal gap to the second hole which has specific designed geometry for external film cooling. The effect of design parameters, such as, offset distance between two-stage holes, gap height, and inclination angle of the first hole, on upstream conjugate heat transfer rate and downstream film cooling effectiveness performance are investigated computationally. An Inconel 617 alloy with variable properties is selected for the solid material. The conjugate heat transfer and film cooling characteristics of MSCS are analyzed across blowing ratios of Br = 1 and 2 for density ratio, 2. This study presents upstream wall temperature distributions due to conjugate heat transfer for different gap design parameters. The maximum film cooling effectiveness with upstream conjugate heat transfer is less than adiabatic film cooling effectiveness by 24–34%. However, the full coverage of cooling effectiveness in spanwise direction can be obtained using internal cooling with conjugate heat transfer, whereas adiabatic film cooling effectiveness has narrow distribution.

Improving Efficiency in Robot Assisted Belt Grinding of High Performance Materials

2014 ◽  
Vol 907 ◽  
pp. 139-149 ◽  
Author(s):  
Eckart Uhlmann ◽  
Florian Heitmüller
Keyword(s):  
Gas Turbines ◽  
High Performance ◽  
Scale Effects ◽  
Turbine Blades ◽  
Repair Process ◽  
Industrial Robots ◽  
Robot Assisted ◽  
Belt Grinding ◽  
Economy Of Scale ◽  
The Individual

In gas turbines and turbo jet engines, high performance materials such as nickel-based alloys are widely used for blades and vanes. In the case of repair, finishing of complex turbine blades made of high performance materials is carried out predominantly manually. The repair process is therefore quite time consuming. And the costs of presently available repair strategies, especially for integrated parts, are high, due to the individual process planning and great amount of manually performed work steps. Moreover, there are severe risks of partial damage during manually conducted repair. All that leads to the fact that economy of scale effects remain widely unused for repair tasks, although the piece number of components to be repaired is increasing significantly. In the future, a persistent automation of the repair process chain should be achieved by developing adaptive robot assisted finishing strategies. The goal of this research is to use the automation potential for repair tasks by developing a technology that enables industrial robots to re-contour turbine blades via force controlled belt grinding.

Numerical investigation of non-uniform flow in twin-silo combustors and impact on axial turbine stage performance

2021 ◽  
pp. 095765092199394
Author(s):  
Hafiz M Hassan ◽  
Adeel Javed ◽  
Asif H Khoja ◽  
Majid Ali ◽  
Muhammad B Sajid
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Internal Flow ◽  
Large Temperature ◽  
Clear Understanding ◽  
Gas Temperature ◽  
Turbine Stage ◽  
Flow Angle ◽  
Axial Turbine ◽  
Stage Performance

A clear understanding of the flow characteristics in the older generation of industrial gas turbines operating with silo combustors is important for potential upgrades. Non-uniformities in the form of circumferential and radial variations in internal flow properties can have a significant impact on the gas turbine stage performance and durability. This paper presents a comprehensive study of the underlying internal flow features involved in the advent of non-uniformities from twin-silo combustors and their propagation through a single axial turbine stage of the Siemens v94.2 industrial gas turbine. Results indicate the formation of strong vortical structures alongside large temperature, pressure, velocity, and flow angle deviations that are mostly located in the top and bottom sections of the turbine stage caused by the excessive flow turning in the upstream tandem silo combustors. A favorable validation of the simulated exhaust gas temperature (EGT) profile is also achieved via comparison with the measured data. A drop in isentropic efficiency and power output equivalent to 2.28% points and 2.1 MW, respectively is observed at baseload compared to an ideal straight hot gas path reference case. Furthermore, the analysis of internal flow topography identifies the underperforming turbine blading due to the upstream non-uniformities. The findings not only have implications for the turbine aerothermodynamic design, but also the combustor layout from a repowering perspective.

Compositional Analysis of Organosolv Poplar Lignin by Using High-Performance Liquid Chromatography/High-resolution Multi-stage Tandem Mass Spectrometry

2021 ◽  
Author(s):  
Jifa Zhang ◽  
Yuan Jiang ◽  
Leah F Easterling ◽  
Anton Anster ◽  
Wanru Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Compositional Analysis ◽  
Complex Mixtures ◽  
Tandem Mass ◽  
Multi Stage ◽  
The Individual ◽  
Environmentally Friendly Process

Organosolv treatment is an efficient and environmentally friendly process to degrade lignin into small compounds. The capability of characterizing the individual compounds in the complex mixtures formed upon organosolv treatment...

Comparison of Transient Modeling Techniques for a Micro Turbine Engine

2006 ◽  
Author(s):  
Craig R. Davison ◽  
A. M. Birk
Keyword(s):  
Gas Turbines ◽  
Relative Size ◽  
Rate Of Change ◽  
Single Stage ◽  
Radial Compression ◽  
Shaft Speed ◽  
Transient Effects ◽  
Rates Of Change ◽  
Experimental Apparatus ◽  
Transient Modeling

A large number of papers have been published on transient modeling of large industrial and military gas turbines. Few, however, have examined micro turbines. The decrease in size affects the relative rates of change of shaft speed, gas dynamics and heat soak. This paper compares the modeled transient effects of a micro turbojet engine comprised of a single stage of radial compression and a single stage of axial expansion, with a diameter of 12cm. The model was validated with experimental data. Several forms of the model were produced starting with the shaft and fuel transients. Conservation of mass, and then energy, was subsequently added for the compressor, combustor and turbine, and a large inlet plenum that was part of the experimental apparatus. Heat soak to the engine body was incorporated into both the shaft and energy models. Heat soak was considered in the compressor, combustor and turbine. Since the engine diameter appears in the differential equations to different powers, the relative rates of change vary with diameter. The rate of change of shaft speed is very strongly influenced. The responses of the different transient effects are compared. The relative solution times are also discussed, since the relative size of the required time steps changes when compared to a large engine.

AUTOMATED OPERATIONAL SCHEDULING SYSTEM FOR MULTI-STAGE PRODUCTION: MATHEMATICAL MODEL AND SOFTWARE IMPLEMENTATION

2021 ◽  
Vol 3 (102) ◽  
pp. 18-37
Author(s):  
OXANA S. LOGUNOVA ◽  
MIKHAIL B. ARKULIS
Keyword(s):  
Mathematical Model ◽  
Raw Materials ◽  
Software Implementation ◽  
Scheduling System ◽  
Operation Conditions ◽  
Multi Stage ◽  
Complete Set ◽  
Wip Inventory ◽  
Production Areas ◽  
Strip Production

The purpose of the study is to improve the efficiency of production areas of multi-stage production with the possibility of rational use of equipment capacity and stocks of WIP inventory in the operation conditions of the automated operational scheduling system. Features of the considered problem regarding operative calendar planning are: necessity of processing raw materials at several stages according to the flow chart; an array of the equipment which demands division of work into three periods for each party; availability of planned and unscheduled equipment downtime; necessity to complete set of orders from several suborders; availability of incomplete production in a warehouse; restrictions in order and timing of orders. In the work, the authors construct a mathematical model with the use of multidimensional matroids with structured elements in the construction of free time scale for equipment loading. The research was carried out for a metallurgical plant at the cold strip production site...

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