Multiobjective Optimization for Duct and Strut Design of an Annular Exhaust Diffuser

2012 ◽  
Author(s):  
Philipp Schaefer ◽  
Willy H. Hofmann ◽  
Peter-Anton Gieß
Keyword(s):  
Experimental Data ◽  
Multiobjective Optimization ◽  
Evolutionary Strategies ◽  
Test Model ◽  
Heavy Duty ◽  
Aerodynamic Optimization ◽  
Inlet Conditions ◽  
Heavy Duty Gas Turbine ◽  
Set Up ◽  
The Impact

This paper describes the aerodynamic optimization of a typical exhaust diffuser for a heavy duty gas turbine. The objective is to maximize diffuser performance and, in this way, pressure recovery by optimizing the geometry for two given inlet conditions. To validate and adjust the numerical set-up, experimental data from measurements on the test model is used. The numerical results obtained by using TRACE compares with the experimental results. An optimization process is applied using the framework AutoOpti developed by DLR, which combines evolutionary strategies with surrogate models in order to select optimal geometric parameters. Finally, the differences between the baseline and several optimized designs are discussed and the impact of different parameters on diffuser performance is demonstrated.

Impact of Different Film-Cooling Modes at Trailing Edge on the Aerodynamic Performance of Heavy Duty Gas Turbine Cascade

2011 ◽  
Vol 84-85 ◽  
pp. 259-263
Author(s):  
Xun Liu ◽  
Song Tao Wang ◽  
Xun Zhou ◽  
Guo Tai Feng
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Large Mass ◽  
Turbine Cascade ◽  
Heavy Duty ◽  
Trailing Edge ◽  
Central Difference ◽  
Adiabatic Effectiveness ◽  
Heavy Duty Gas Turbine ◽  
The Impact

In this paper, the trailing edge film cooling flow field of a heavy duty gas turbine cascade has been studied by central difference scheme and multi-block grid technique. The research is based on the three-dimensional N-S equation solver. By way of analysis of the temperature field, the distribution of profile pressure, and the distribution of film-cooling adiabatic effectiveness in the region of trailing edge with different cool air injection mass and different angles, it is found that the impact on the film-cooling adiabatic effectiveness is slightly by changing the injection mass. The distribution of profile pressure dropped intensely at the pressure side near the injection holes line with the large mass cooling air. The cooling effect is good in the region of trailing edge while the injection air is along the direction of stream.

Experimental and Simulation of a Cam and Translated Roller Follower Over a Range of Speeds

2016 ◽  
Author(s):  
Louay S. Yousuf ◽  
Dan B. Marghitu
Keyword(s):  
Experimental Data ◽  
Lyapunov Exponent ◽  
High Resolution ◽  
Lyapunov Exponents ◽  
Planar Motion ◽  
Largest Lyapunov Exponents ◽  
Set Up ◽  
The Impact ◽  
Impact With Friction

In this study a cam and follower mechanism is analyzed. There is a clearance between the follower and the guide. The mechanism is analyzed using SolidWorks simulations taking into account the impact and the friction between the roller follower and the guide. Four different follower guide’s clearances have been used in the simulations like 0.5, 1, 1.5, and 2 mm. An experimental set up is developed to capture the general planar motion of the cam and follower. The measures of the cam and the follower positions are obtained through high-resolution optical encoders (markers). The effect of follower guide’s clearance is investigated for different cam rotational speeds such as 100, 200, 300, 400, 500, 600, 700 and 800 R.P.M. Impact with friction is considered in our study to calculate the Lyapunov exponent. The largest Lyapunov exponents for the simulated and experimental data are analyzed and selected.

Design Improvement Survey for NOx Emissions Reduction of a Heavy-Duty Gas Turbine Partially Premixed Fuel Nozzle Operating With Natural Gas: Experimental Campaign

2015 ◽  
Author(s):  
Matteo Cerutti ◽  
Roberto Modi ◽  
Danielle Kalitan ◽  
Kapil K. Singh
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Gas Turbine ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Fuel Nozzle ◽  
Partially Premixed ◽  
Heavy Duty Gas Turbine ◽  
The Impact

As government regulations become increasingly strict with regards to combustion pollutant emissions, new gas turbine combustor designs must produce lower NOx while also maintaining acceptable combustor operability. The design and implementation of an efficient fuel/air premixer is paramount to achieving low emissions. Options for improving the design of a natural gas fired heavy-duty gas turbine partially premixed fuel nozzle have been considered in the current study. In particular, the study focused on fuel injection and pilot/main interaction at high pressure and high inlet temperature. NOx emissions results have been reported and analyzed for a baseline nozzle first. Available experience is shared in this paper in the form of a NOx correlative model, giving evidence of the consistency of current results with past campaigns. Subsequently, new fuel nozzle premixer designs have been investigated and compared, mainly in terms of NOx emissions performance. The operating range of investigation has been preliminarily checked by means of a flame stability assessment. Adequate margin to lean blow out and thermo-acoustic instabilities onset has been found while also maintaining acceptable CO emissions. NOx emission data were collected over a variety of fuel/air ratios and pilot/main splits for all the fuel nozzle configurations. Results clearly indicated the most effective design option in reducing NOx. In addition, the impact of each design modification has been quantified and the baseline correlative NOx emissions model calibrated to describe the new fuel nozzles behavior. Effect of inlet air pressure has been evaluated and included in the models, allowing the extensive use of less costly reduced pressure test campaigns hereafter. Although the observed effect of combustor pressure drop on NOx is not dominant for this particular fuel nozzle, sensitivity has been performed to consolidate gathered experience and to make the model able to evaluate even small design changes affecting pressure drop.

CFD Studies on a Large Diameter Jet Impingement Flow

2004 ◽  
Author(s):  
Zhiguo Zhang ◽  
Mounir Ibrahim
Keyword(s):  
Experimental Data ◽  
Computational Study ◽  
Large Diameter ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Reynolds Numbers ◽  
University Of Minnesota ◽  
Inlet Conditions ◽  
The University ◽  
The Impact

This paper presents computational study for a large diameter (216 mm) and small space ratios (S/D = 0.25 and 0.5) jet impingement flow. CFD-ACE code was used as the computational tools; the code was first validated by comparing its predictions with both CFD and experimental data from the literature. Then, the study was performed for two different Reynolds numbers: 7600, 17700 and two different space ratios: 0.25 and 0.5. Also two different turbulence models were utilized in this study: low Reynolds number turbulent k-ε and k-ω. The CFD results were compared with flow visualization results conducted at the University of Minnesota for the same configurations. The impact of choosing different inlet conditions on the CFD flow field was examined. The k-ε model showed greater sensitivity to the selection of the inlet conditions. Moreover, the k-ω model showed much better agreement with the experimental data than the k-ε model.

Experimental Study on the Atomization Behavior of Fuel Nozzle of Low Pollution

2011 ◽  
Vol 66-68 ◽  
pp. 307-310
Author(s):  
Xu Li ◽  
Kai Liu
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Combustion Efficiency ◽  
Outlet Temperature ◽  
Design Development ◽  
Heavy Duty ◽  
Group Design ◽  
Fuel Nozzle ◽  
Heavy Duty Gas Turbine ◽  
Reliable Basis

Experimental investigation results of the fuel nozzle group in a heavy-duty gas turbine are presented. Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and distribution using LDV/PDPA system. These experimental data have provided reliable basis for the nozzle group design, development and operation.

Integrated Experimental and Numerical Approach for Fuel-Air Mixing Prediction in a Heavy-Duty Gas Turbine LP Burner

2000 ◽  
Vol 123 (4) ◽  
pp. 803-809 ◽  
Author(s):  
G. Mori ◽  
S. Razore ◽  
M. Ubaldi ◽  
P. Zunino
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Numerical Procedure ◽  
Turbulence Models ◽  
Mie Scattering ◽  
Optical Measurements ◽  
Heavy Duty ◽  
Experimental Apparatus ◽  
Air Mixing ◽  
Heavy Duty Gas Turbine

An integrated experimental-numerical procedure has been developed for fuel-air mixing prediction in a heavy-duty gas turbine burner. Optical measurements of the degree of mixing have been performed in a full-scale test rig operating with cold flow. Experimental data have been utilized to validate a CFD RANS numerical model. In fact, it is recognized that the turbulence behavior of jets in swirling air-flow stream is not accurately described by standard k-ε turbulence models; therefore advanced turbulence models have been assessed by means of experimental data. The degree of mixing between simulated fuel and air streams has been evaluated at the burner exit section by means of a planar Mie scattering technique. The experimental apparatus consists of a pulsed Nd:YAG laser and a high resolution CCD video camera connected to a frame grabber. The acquired instantaneous images have been processed through specific procedures that also take into account the laser beam spatial nonuniformity. A second-order discretization scheme with a RSM turbulence model gives the best accordance with the experimental data. Such CFD model will be part of a more general method addressed to numerical prediction of turbulent combustion flames in LP technology.

Effect of Natural Gas Composition on Low NOx Burners Operation in Heavy Duty Gas Turbine

2019 ◽  
Author(s):  
Serena Romano ◽  
Matteo Cerutti ◽  
Giovanni Riccio ◽  
Antonio Andreini ◽  
Christian Romano
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Fuel Composition ◽  
Gas Composition ◽  
Heavy Duty ◽  
Wide Range ◽  
Annular Combustor ◽  
Heavy Duty Gas Turbine ◽  
The Impact

Abstract Development of lean-premixed combustion technology with low emissions and stable operation in an increasingly wide range of operating conditions requires a deep understanding of the mechanisms that affect the combustion performance or even the operability of the entire gas turbine. Due to the relative wide range of natural gas composition supplies and the increased demand from Oil&Gas customers to burn unprocessed gas as well as LNG with notable higher hydrocarbons (C2+) content; the impact on gas turbine operability and combustion related aspects has been matter of several studies. In this paper, results of experimental test campaign of an annular combustor for heavy-duty gas turbine are presented with focus on the effect of fuel composition on both emissions and flame stability. Test campaign involved two different facilities, a full annular combustor rig and a full-scale prototype engine fed with different fuel mixtures of natural gas with small to moderate C2H6 content. Emissions trends and blowout for several operating conditions and burner configurations have been analyzed. Modifications to the burner geometry and fuel injection optimization have shown to be able to reach a good trade-off while keeping low NOx emissions in stable operating conditions for varying fuel composition.

Impact of the Inflow Conditions on the Heavy-Duty Gas Turbine Exhaust Diffuser Performance

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Vladimir Vassiliev ◽  
Stefan Irmisch ◽  
Samer Abdel-Wahab ◽  
Andrey Granovskiy
Keyword(s):  
Pressure Distribution ◽  
Gas Turbines ◽  
Field Measurements ◽  
Heavy Duty ◽  
Flow Angle ◽  
Heavy Duty Gas Turbine ◽  
Gas Turbine Exhaust ◽  
The Impact ◽  
Inflow Conditions ◽  
Turbine Exhaust

The flow in exhaust diffusers along with the channel geometry strongly depends on the inflow conditions, including Mach number level, total pressure distribution, flow angle, and turbulence. In the first part of this paper, the impact of these parameters is analyzed using computational fluid dynamics, experimental data from the test rig, and field measurements. A widespread opinion is that the optimal condition for the diffuser is an axial uniform inflow. However, it is shown in this paper that nonuniform pressure distribution compared with a uniform one can lead to better diffuser performance and that a moderate residual swirl can improve the performance as well. In the second part of this paper, the minimization of exhaust losses in heavy-duty gas turbines is discussed and illustrated by two practical examples.

scholarly journals Evaluation of JULES-crop performance against site observations of irrigated maize from Mead, Nebraska

2016 ◽  
Author(s):  
Karina Williams ◽  
Jemma Gornall ◽  
Anna Harper ◽  
Andy Wiltshire ◽  
Debbie Hemming ◽  
...  
Keyword(s):  
Input Parameter ◽  
Model Development ◽  
Crop Productivity ◽  
Crop Model ◽  
Test Model ◽  
Area Index ◽  
Crop Varieties ◽  
Weather And Climate ◽  
Set Up ◽  
The Impact

Abstract. The JULES-crop model (Osborne et al., 2015) is a parameterisation of crops within the Joint UK Land Environment Simulator (JULES), which aims to simulate both the impact of weather and climate on crop productivity and the impact of crop-lands on weather and climate. In this evaluation paper, observations of maize at three FLUXNET sites in Nebraska (US-Ne1, US-Ne2, US-Ne3) are used to test model assumptions and make appropriate input parameter choices. JULES runs are performed for the irrigated sites (US-Ne1 and US-Ne2) both with the crop model switched off (prescribing leaf area index (LAI) and canopy height) and with the crop model switched on. These are compared against GPP and carbon pool FLUXNET observations. We use the results to point to future priorities for model development and describe how our methodology can be adapted to set up model runs for other sites and crop varieties. The implications of our results on the choice of parameters and settings to be used in global runs of JULES-crop are also discussed.

Preliminary Exploration of the Dynamic Model and Experiment on an Impact between a Tennis Ball and Racket

2014 ◽  
Vol 494-495 ◽  
pp. 297-300
Author(s):  
Hui Hui Hong ◽  
Liang Han
Keyword(s):  
Experimental Data ◽  
Dynamic Model ◽  
Sports Injuries ◽  
Test System ◽  
Experimental Results ◽  
Tennis Ball ◽  
Preliminary Results ◽  
Preliminary Study ◽  
Set Up ◽  
The Impact

The research on an impact between a tennis ball and racket is very significant to improve the level of tennis and reduce the sports injuries. A preliminary study on an impact between a tennis ball and racket is carried out in this paper. It is composed of four parts: the reference of the existed dynamic model, the experimental set-up, the test system, the collection and analysis of experimental data. The preliminary experimental results are compared with the dynamic model, and the impact dynamic model can be improved after considering every effect on the impact. The preliminary results show that the model can be used to predict the tennis impact on the racket with different inbound velocity.

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