scholarly journals Gas Turbines: Internal Flow Systems Modeling B. K. Sultanian, Cambridge University Press, University Printing House, Shaftesbury Road, Cambridge CB2 8BS, UK. 2018. xviii; 356pp. Illustrated £74.99. ISBN 978-1-107-17009-4.

2019 ◽  
Vol 123 (1266) ◽  
pp. 1302-1302
Author(s):  
Adrian Spencer
Keyword(s):  
Gas Turbines ◽  
Internal Flow ◽  
Systems Modeling ◽  
Cambridge University ◽  
Flow Systems ◽  
Printing House

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.

Secondary Flow Loss Reduction Method by Use of Endwall Contouring in Gas Turbine Cascade Using Optimization Method

2021 ◽  
Author(s):  
Kazuki Yamamoto ◽  
Ryota Uehara ◽  
Shohei Mizuguchi ◽  
Masahiro Miyabe
Keyword(s):  
Boundary Layer ◽  
Secondary Flow ◽  
Gas Turbines ◽  
Cross Flow ◽  
Internal Flow ◽  
Optimization Method ◽  
Loss Reduction ◽  
Turbine Cascade ◽  
Flow Loss ◽  
Endwall Contouring

Abstract High efficiency is strongly demanded for gas turbines to reduce CO2 emissions. In order to improve the efficiency of gas turbines, the turbine inlet temperature is being raised higher. In that case, the turbine blade loading is higher and secondary flow loss becomes a major source of aerodynamic losses due to the interaction between the horseshoe vortex and the strong endwall cross flow. One of the authors have optimized a boundary layer fence which is a partial vane to prevent cross-flow from pressure-side to suction-side between blade to blade. However, it was also found that installing the fence leads to increase another loss due to tip vortex, wake and viscosity. Therefore, in this paper, we focused on the endwall contouring and the positive effect findings from the boundary layer fence were used to study its optimal shape. Firstly, the relationship between the location of the endwall contouring and the internal flow within the turbine cascade was investigated. Two patterns of contouring were made, one is only convex and another is just concave, and the secondary flow behavior of the turbine cascade was investigated respectively. Secondly, the shape was designed and the loss reduction effect was investigated by using optimization method. The optimized shape was manufactured by 3D-printer and experiment was conducted using cascade wind tunnel. The total pressure distributions were measured and compared with CFD results. Furthermore, flow near the endwall and the internal flow of the turbine cascade was experimentally visualized. The internal flow in the case of a flat wall (without contouring), with a fence, and with optimized endwall contouring were compared by experiment and CFD to extract the each feature.

An Analysis Methodology for Internal Swirling Flow Systems With a Rotating Wall

1991 ◽  
Vol 113 (1) ◽  
pp. 83-90 ◽  
Author(s):  
M. Williams ◽  
W. C. Chen ◽  
G. Bache´ ◽  
A. Eastland
Keyword(s):  
Reynolds Number ◽  
Turbulence Model ◽  
Gas Turbines ◽  
High Reynolds Number ◽  
Rotating Disk ◽  
Rotating Wall ◽  
Analysis Methodology ◽  
Flow Systems ◽  
Flow Through ◽  
High Reynolds

This paper presents an analysis methodology for the calculation of the flow through internal flow components with a rotating wall such as annular seals, impeller cavities, and enclosed rotating disks. These flow systems are standard components in gas turbines and cryogenic engines and are characterized by subsonic viscous flow and elliptic pressure effects. The Reynolds-averaged Navier-Stokes equations for turbulent flow are used to model swirling axisymmetric flow. Bulk-flow or velocity profile assumptions aren’t required. Turbulence transport is assumed to be governed by the standard two-equation high Reynolds number turbulence model. A low Reynolds number turbulence model is also used for comparison purposes. The high Reynolds number turbulence model is found to be more practical. A novel treatment of the radial/swirl equation source terms is developed and used to provide enhanced convergence. Homogeneous wall roughness effects are accounted for. To verify the analysis methodology, the flow through Yamada seals, an enclosed rotating disk, and a rotating disk in a housing with throughflow are calculated. The calculation results are compared to experimental data. The calculated results show good agreement with the experimental results.

On chemical reactions in internal flow systems

1960 ◽  
Vol 9 (1) ◽  
pp. 157-168 ◽  
Author(s):  
Paul L. Chambré
Keyword(s):  
Chemical Reactions ◽  
Internal Flow ◽  
Flow Systems

Manufacture, Characterization and Stability Limits of an AM Prefilming Air-Blast Atomizer

2019 ◽  
Author(s):  
Andrew P. Crayford ◽  
Franck Lacan ◽  
Jon Runyon ◽  
Philip J. Bowen ◽  
Shrinivas Balwadkar ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Pressure Drop ◽  
Gas Turbines ◽  
Air Flow ◽  
Internal Flow ◽  
Flow Path ◽  
Component Part ◽  
Flame Stability ◽  
Flow Rates ◽  
Fuel Flow

Abstract With the recent advancement of metallic additive manufacturing (AM), it is perceived that future gas turbines will be manufactured with significantly fewer parts, leading to both financial and safety improvements achieved from reductions in weight, assembly processes and failure modes associated with welded parts. In addition the design and manufacture of highly intricate parts such as fuel atomizers become free from the constraints of tooling, facilitating more complex internal flow geometries to be conceived which afford improved atomization, flame stability and hence combustion efficiency. However, it is noted that increased dimensional tolerances and surface roughness resulting from this manufacturing technique can detrimentally impact internal air and fuel flow paths and hence warrant further investigation. In this study a small-scale (200kW) pre-filming airblast atomizer, based on the Parker Hannifin commercial concept, and typical of injectors utilized in RQL aviation combustors, was manufactured by Cardiff School of Engineering’s High Value Manufacturing Laboratories. Direct metal laser sintering, was utilized to produce a fully operational single component part, manufactured in 316-grade stainless steel using a Renishaw AM250 system, providing a part with measured surface roughness (Ra) values of 12–26 μm in agreement with expected values reported in the literature. Operation of the injector as a single fluid atomizer demonstrated that the fuel channel and integrated swirlers were sufficiently accurate and concentric to result in a uniform spray pattern, displaying global liquid sheet structures which were in agreement with those previously reported. However, the effective area of the atomizer’s air-flow path, when evaluated using differential pressure measurements, was shown to be smaller than predicted, resulting in an increased pressure drop. Laser diffraction droplet sizing was utilized to evaluate the global SMD of the prefilming airblast water spray at atmospheric conditions, across a range of air to liquid ratios. SMD’s between 4.2–115μm were measured at corresponding air-flow rates of 3–25 g/s, with droplet sizes observed to decrease exponentially at higher air-flow rates. This data is again in excellent agreement with SMD correlations previously proposed. Flame stability experiments conducted at ambient pressure and elevated air temperature, demonstrated the stability of a conventional (JET A-1) fuel flame across a range of air and fuel flow rates, representative of pressure drops and AFRs in commercial operation. Further post-processing of the internal flow path walls and swirl vanes to reduce surface roughness is anticipated to result in a lower pressure drop across the air-path geometry, highlighting the potential for further improvements in AM injector performance.

Internal flow systems

Thermofluids ◽  
1996 ◽  
pp. 49-53
Author(s):  
Keith Sherwin ◽  
Michael Horsley
Keyword(s):  
Internal Flow ◽  
Flow Systems

Probabilistic Optimization of Two-Phase Flow Using Bayesian Models

2014 ◽  
Author(s):  
Kenji Miki ◽  
Arun Subramaniyan ◽  
Madhusudan Pai ◽  
Preetham Balasubramanyam
Keyword(s):  
Gas Turbines ◽  
Two Phase Flow ◽  
Flow System ◽  
Probabilistic Approach ◽  
Computational Cost ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Flow Configuration ◽  
Flow Systems

Gas-liquid two-phase flows are encountered in a variety of applications such as turbo-machinery flows, gas-turbines, ram-jet and scram-jets, automotive engines and aircraft engines. Designing systems to control such flows is enormously challenging owing to the addition of new non-dimensional groups that characterize the two-phase flow system compared to a single-phase flow. Additionally, two-phase flows can exhibit non-linear hydrodynamic instabilities that determine the overall behavior of the system. In this study, we choose a generic two-phase flow configuration that exhibits known complexities in realistic two-phase flow systems. The goal of the study is to optimize the geometry of the two-phase flow configuration with minimal computational cost. We propose a probabilistic approach to model the stochastic system and optimize the two-phase flow system under uncertain inputs. The potential benefits of the approach are highlighted along with future directions for using probabilistic design techniques to optimize two-phase flow systems.

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