3D Unsteady Multi-Stage CFD Analysis of Combustor-Turbine Hot Streak Migration

2014 ◽  
Author(s):  
Khosro Mollahosseini ◽  
Fred G. Borns ◽  
Paul T. Couey ◽  
Jean-Charles Bonaccorsi ◽  
Alain Demeulenaere
Keyword(s):  
High Performance ◽  
Fluid Dynamic ◽  
Design History ◽  
Gas Temperature ◽  
Computer Clusters ◽  
Multi Stage ◽  
Nickel Base ◽  
Hot Streak ◽  
Turbine Airfoils ◽  
Cooling Air

With gas temperatures far exceeding the melting point of nickel-base alloys, advanced cooling schemes are essential to meet the desired mission life of turbine airfoils. Naturally, combustion systems produce gas-temperature non-uniformity in the exiting flowfield. Downstream turbine components must be tolerant to the maximum anticipated gas temperatures. On the other hand, excessive use of cooling air reduces engine efficiency and compromises combustor durability. Throughout gas turbine design history it has been the desire of Turbine Aerodynamicists to be able to compute combustor hot streak migration and mixing through multiple turbine airfoil stages. Typically, hot streak migration studies have been performed using (a) mixing-plane models between rotating and stationery domains or (b) unsteady simulations in which the flowpath annulus is represented by a segment containing airfoil counts that are integer multiples in each blade row or (c) Non-Linear Harmonic methods. With the development of highly-parallelized Computational Fluid Dynamic (CFD) codes driving high performance computer clusters simulation of combustor hot streak migration through multiple High Pressure (HP) turbine stages using an unsteady, 360° (full-annulus) model can be achieved. To this end, Honeywell, in collaboration with Numeca Corporation, has performed a study to evaluate the state-of the art for computation of the effect on second-stage HP turbine nozzle metal temperatures of combustor hot streaks migrated through the first-stage of a two-stage HP turbine.

Pilot Plant Study on Microaerobic Self-Granulated Sludge Process (Multi-Stage Reversing Flow Bioreactor: MRB)

1991 ◽  
Vol 23 (4-6) ◽  
pp. 973-980 ◽  
Author(s):  
M. Takahashi ◽  
S. Kyosai
Keyword(s):  
Pilot Plant ◽  
High Performance ◽  
Anaerobic Bacteria ◽  
Domestic Wastewater ◽  
Public Works ◽  
Symbiotic Interaction ◽  
Sulfate Reducing ◽  
Pellet Formation ◽  
Multi Stage ◽  
Domestic Wastewater Treatment

A Multi-stage Reversing flow Bioreactor (MRB) was developed by the Public Works Research Institute in 1986. It utilizes the symbiotic interaction between anaerobic bacteria (sulfate reducing bacteria) and microaerobic bacteria (Beggiatoa=filamentous sulfur oxidizing bacteria) for self-granulated pellet formation. A MRB Pilot plant for domestic wastewater treatment (design capacity was 225 m3/day) was constructed in 1988. After several modifications of the initial design, stable pellet formation and high performance were achieved. This paper describes the results of the pilot plant operation.

Using computer clusters for processing spatial-temporal data streams in data acquisition systems

2018 ◽  
Vol 935 (5) ◽  
pp. 54-63
Author(s):  
A.A. Maiorov ◽  
A.V. Materuhin ◽  
I.N. Kondaurov
Keyword(s):  
Data Acquisition ◽  
Data Streams ◽  
Spatial Data ◽  
High Performance ◽  
Temporal Data ◽  
Cyberphysical Systems ◽  
Software Environment ◽  
Computer Clusters ◽  
Data Acquisition Systems ◽  
Essential Components

Geoinformation technologies are now becoming “end-to-end” technologies of the new digital economy. There is a need for solutions for efficient processing of spatial and spatio-temporal data that could be applied in various sectors of this new economy. Such solutions are necessary, for example, for cyberphysical systems. Essential components of cyberphysical systems are high-performance and easy-scalable data acquisition systems based on smart geosensor networks. This article discusses the problem of choosing a software environment for this kind of systems, provides a review and a comparative analysis of various open source software environments designed for large spatial data and spatial-temporal data streams processing in computer clusters. It is shown that the software framework STARK can be used to process spatial-temporal data streams in spatial-temporal data streams. An extension of the STARK class system based on the type system for spatial-temporal data streams developed by one of the authors of this article is proposed. The models and data representations obtained as a result of the proposed expansion can be used not only for processing spatial-temporal data streams in data acquisition systems based on smart geosensor networks, but also for processing spatial-temporal data streams in various purposes geoinformation systems that use processing data in computer clusters.

scholarly journals Low-Process–Voltage–Temperature-Sensitivity Multi-Stage Timing Monitor for System-on-Chip Applications

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1587
Author(s):  
Duo Sheng ◽  
Hsueh-Ru Lin ◽  
Li Tai
Keyword(s):  
High Performance ◽  
Power Reduction ◽  
System On Chip ◽  
Timing Information ◽  
Multi Stage ◽  
Dynamic Voltage ◽  
And Performance ◽  
On Chip ◽  
Maximum Measurement ◽  
Maximum Measurement Error

High performance and complex system-on-chip (SoC) design require a throughput and stable timing monitor to reduce the impacts of uncertain timing and implement the dynamic voltage and frequency scaling (DVFS) scheme for overall power reduction. This paper presents a multi-stage timing monitor, combining three timing-monitoring stages to achieve a high timing-monitoring resolution and a wide timing-monitoring range simultaneously. Additionally, because the proposed timing monitor has high immunity to the process–voltage–temperature (PVT) variation, it provides a more stable time-monitoring results. The time-monitoring resolution and range of the proposed timing monitor are 47 ps and 2.2 µs, respectively, and the maximum measurement error is 0.06%. Therefore, the proposed multi-stage timing monitor provides not only the timing information of the specified signals to maintain the functionality and performance of the SoC, but also makes the operation of the DVFS scheme more efficient and accurate in SoC design.

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...

scholarly journals Determination of Zero Dimensional, Apparent Devolatilization Kinetics for Biomass Particles at Suspension Firing Conditions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1018
Author(s):  
Anna Espekvist ◽  
Tian Li ◽  
Peter Glarborg ◽  
Terese Løvås ◽  
Peter Arendt Jensen
Keyword(s):  
Aspect Ratio ◽  
Particle Density ◽  
Fluid Dynamic ◽  
Particle Radius ◽  
Biomass Combustion ◽  
Least Squares Regression ◽  
Gas Temperature ◽  
Density Maximum ◽  
Parameter Ranges ◽  
The Impact

As part of the strive for a carbon neutral energy production, biomass combustion has been widely implemented in retrofitted coal burners. Modeling aids substantially in prediction of biomass flame behavior and thus in boiler chamber conditions. In this work, a simple model for devolatilization of biomass at conditions relevant for suspension firing is presented. It employs Arrhenius parameters in a single first order (SFOR) devolatilization reaction, where the effects of kinetics and heat transfer limitations are lumped together. In this way, a biomass particle can be modeled as a zero dimensional, isothermal particle, facilitating computational fluid dynamic calculations of boiler chambers. The zero dimensional model includes the effects of particle aspect ratio, particle density, maximum gas temperature, and particle radius. It is developed using the multivariate data analysis method, partial least squares regression, and is validated against a more rigorous semi-2D devolatilization model. The model has the capability to predict devolatilization time for conditions in the parameter ranges; radius (39–1569 μμm), density (700–1300 kg/m3), gas temperature (1300–1900 K), aspect ratio (1.01–8). Results show that the particle radius and gas phase temperature have a large influence on the devolatilization rate, and the aspect ratio has a comparatively smaller effect, which, however, cannot be neglected. The impact of aspect ratio levels off as it increases. The model is suitable for use as stand alone or as a submodel for biomass particle devolatilization in CFD models.

Continuous adjoint aerodynamic optimization design for multi-stage gas turbine with cooling air

2017 ◽  
Vol 89 (3) ◽  
pp. 444-456
Author(s):  
Lei Chen ◽  
Jiang Chen
Keyword(s):  
Gas Turbine ◽  
Optimization Design ◽  
Adjoint Method ◽  
Air Injection ◽  
Aerodynamic Optimization ◽  
Content Type ◽  
Multi Stage ◽  
Surface Code ◽  
Cooling Air ◽  
Continuous Adjoint

Purpose This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method. Design/methodology/approach Continuous adjoint method is combined with the S2 surface code. Findings The optimization of the stagger angles, stacking lines and the passage can improve the attack angles and restrain the development of the boundary, reducing the secondary flow loss caused by the cooling air injection. Practical implications The aerodynamic performance of the gas turbine can be improved via the optimization of blade and passage based on the adjoint method. Originality/value The results of the first study on the adjoint method applied to the S2 surface through flow calculation including the cooling air effect are presented.

Analysis of the Vortex Series Around Tabs in the Bent Marine Exhaust Ejector

2017 ◽  
Author(s):  
Aoyu Ren ◽  
Hai’ou Sun ◽  
Zhongyi Wang ◽  
Xudong Chen
Keyword(s):  
High Performance ◽  
Streamwise Vortex ◽  
Streamwise Vorticity ◽  
Gas Temperature ◽  
Cross Sectional ◽  
Swirl Angle ◽  
Calculation Results ◽  
Inlet Swirl ◽  
Hybrid Grid ◽  
Tube Exit

In order to facilitate the application of special structural ejectors, which improve the ability of pumping the secondary flow without additional power consumption, reducing the flue gas temperature at the export and enhancing the ship viability under the threat of infrared guided weapons, this paper regardes the 90 ° bend tabs ejector as the research object according to the actual situation of our country’s ships, focuses on the inner effect of the existence of tabs on the flow field in the bent channel, and mainly revealed the transformation of the vortex around the tabs, for providing an explanation to a certain extent about how the tabs affect the macro performance of ejector. With ANSYS software, ring 8 equilateral triangles tabs were designed with 120 ° wall surface mounting angle. With adjusting the blocking ratio of the main outlet area based on the similar zoom, setting inlet swirl angle, and building a hybrid grid to compute, the vortex structure distribution and the development around tabs were observed. The maximum vorticity of vortex at different distances in the mixing tube to the mix tube exit had been calculated to reflect the change of vortex intensity. The final results show that although the streamwise vortices are still located in an axial symmetrical distribution, the swirl angle leads to an uneven distribution of the flow on both sides of a single tab. The inlet swirl angle can make the symmetry of the steamwise vortex vaguer, but the effect of the convection to the vortex is enhanced. The blocking area ratio of the nozzle cross-sectional surface has a large effect on the vorticity of the streamwise vortex. The calculation results show that the larger the blocking area is, the greater the vorticity of streamwise vortex is, which also shows that when the tab shape is fixed, the tab surface area will increase the streamwise vorticity. Through the above research, the shape and the change of the streamwise vortex generated by the tabs in the bent ejector are clearly demonstrated, which can be a reference for the design of high performance bent ejector.

Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine

2000 ◽  
Author(s):  
Daniel J. Dorney ◽  
Douglas L. Sondak
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Single Stage ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Radial Spreading ◽  
Rotor Surface ◽  
Hot Streak ◽  
Turbine Airfoils

Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. In addition, the effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have been quantified. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine geometry operating in high subsonic flow to study the effects of tip clearance on hot streak migration. Baseline simulations were initially performed without hot streaks to compare with the experimental data. Two simulations were then performed with a superimposed combustor hot streak; in the first the tip clearance was set at the experimental value, while in the second the rotor was allowed to scrape along the outer case (i.e., the limit as the tip clearance goes to zero). The predicted results for the baseline simulations show good agreement with the available experimental data. The simulations with the hot streak indicate that the tip clearance increases the radial spreading of the hot fluid, and increases the integrated rotor surface temperature compared to the case without tip clearance.

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