A New Method for Numerical Prediction of Lean Blowout in Aero-Engine Combustor

2013 ◽  
Author(s):  
Zhibo Zhang ◽  
Hongtao Zheng ◽  
Zhiming Li ◽  
Yajun Li ◽  
Gang Pan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Flow Velocity ◽  
Air Temperature ◽  
New Method ◽  
Lean Blowout ◽  
Aero Engine ◽  
Annular Combustor ◽  
Combustion Flow ◽  
Feature Section

Lean blowout (LBO) is one of the most important parameters on combustor performance. A new method named Feature-Section-criterion (FSC) for predicting LBO of aero-engine annular combustor has been put forward in the present work. A CFD software FLUENT has been used to simulate the combustion flow field of an annular combustor. The prediction of LBO with FSC has been done in this paper and the effects of flow velocity, air temperature and droplet averaged-diameter on the LBO of aero-engine combustor have been discussed by using of FSC. The results show that the predictions of FSC are in agreement with corresponding experimental data. This showing that this method for predicting lean blowout is reliable and can be used for engineering applications.

Feature-Section-Criterion for Predicting Lean Blowout and Comparison Research

2013 ◽  
Author(s):  
Zhibo Zhang ◽  
Hongtao Zheng ◽  
Honglei Yang ◽  
Ren Yang ◽  
Qian Liu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
New Method ◽  
Engineering Applications ◽  
Lean Blowout ◽  
Comparison Research ◽  
Annular Combustor ◽  
Combustion Flow ◽  
Feature Section

Lean blowout (LBO) plays an important role in combustor performance. A new method named Feature-Section-criterion (FSC) for predicting the LBO of annular combustor has been put forward and expounded in this paper. A CFD software FLUENT has been used to simulate the combustion flow field of an annular combustor. The process of blowout and effects of flow split among swirlers and primary holes have been researched by using of FSC. The result shows that the predictions of FSC are in agreement with corresponding experimental data. So this method for predicting lean blowout is reliable and can be used for engineering applications.

Flow Field and Hot Streak Migration Through a High Pressure Cooled Vanes With Representative Lean Burn Combustor Outflow

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Tommaso Bacci ◽  
Tommaso Lenzi ◽  
Alessio Picchi ◽  
Lorenzo Mazzei ◽  
Bruno Facchini
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Flow Field ◽  
Fuel Injection ◽  
Leading Edge ◽  
Flame Stabilization ◽  
Lean Burn ◽  
Aero Engine ◽  
University Of Florence ◽  
Hot Streak

Modern lean burn aero-engine combustors make use of relevant swirl degrees for flame stabilization. Moreover, important temperature distortions are generated, in tangential and radial directions, due to discrete fuel injection and liner cooling flows respectively. At the same time, more efficient devices are employed for liner cooling and a less intense mixing with the mainstream occurs. As a result, aggressive swirl fields, high turbulence intensities, and strong hot streaks are achieved at the turbine inlet. In order to understand combustor-turbine flow field interactions, it is mandatory to collect reliable experimental data at representative flow conditions. While the separated effects of temperature, swirl, and turbulence on the first turbine stage have been widely investigated, reduced experimental data is available when it comes to consider all these factors together.In this perspective, an annular three-sector combustor simulator with fully cooled high pressure vanes has been designed and installed at the THT Lab of University of Florence. The test rig is equipped with three axial swirlers, effusion cooled liners, and six film cooled high pressure vanes passages, for a vortex-to-vane count ratio of 1:2. The relative clocking position between swirlers and vanes has been chosen in order to have the leading edge of the central NGV aligned with the central swirler. In order to generate representative conditions, a heated mainstream passes though the axial swirlers of the combustor simulator, while the effusion cooled liners are fed by air at ambient temperature. The resulting flow field exiting from the combustor simulator and approaching the cooled vane can be considered representative of a modern Lean Burn aero engine combustor with swirl angles above ±50 deg, turbulence intensities up to about 28% and maximum-to-minimum temperature ratio of about 1.25. With the final aim of investigating the hot streaks evolution through the cooled high pressure vane, the mean aerothermal field (temperature, pressure, and velocity fields) has been evaluated by means of a five-hole probe equipped with a thermocouple and traversed upstream and downstream of the NGV cascade.

Experimental Studies of the Primary Zone Flow Field and Combustion Performance of a Triple Swirler Combustor

2005 ◽  
Author(s):  
Yunhui Peng ◽  
Quanhong Xu ◽  
Yuzhen Lin
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Fuel Injector ◽  
Lean Blowout ◽  
Combustion Performance ◽  
Primary Zone ◽  
Image Velocimetry ◽  
Aero Engine ◽  
Exit Temperature ◽  
Promising Solution

Improvement of the lean blowout limit and more uniform combustor exit temperature distribution are particularly desirable for future aero engine. A triple swirler combination plus an airblast fuel injector might be a promising solution. The design with the triple swirler plus the airblast fuel injector including design A and B was presented and investigated in this paper. Single rectangle sector module combustor was used in the experiment for lean blowout (LBO), and three cups rectangle sector combustor was used for pattern factor (PF) experiments. The LBO and PF experiment data were provided. The primary zone flow field was measured by PIV (Particle Image Velocimetry) under atmospheric pressure and temperature. The result showed that the design A was a promising design, and the primary jet played very important role for flow field of primary zone. The insight relation between flow field and combustion performance could be found out from this paper.

Comparative Analysis of Flow Field in Mixed and Non Mixed Gas Electrochemical Machining for Aero-Engine Turbine Blade Cooling Holes

2017 ◽  
Vol 868 ◽  
pp. 166-171
Author(s):  
Zhing Yong Li ◽  
Xiu Ting Wei ◽  
Wen Wen Lu ◽  
Qing Wei Cui
Keyword(s):  
Flow Field ◽  
Flow Velocity ◽  
Turbine Blade ◽  
Electrochemical Machining ◽  
Machining Accuracy ◽  
Mixed Gas ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Vortex Zone ◽  
Aero Engine

By the cooling holes in aero-engine turbine blade as the research object, this study focuses on two kinds of ECM methods, which are mix gas added to the nonlinear electrolyte (NaNO3) and non-mixed gas. Mixed and non-mixed gas ECM experiments of turbine blade cooling holes were carried out respectively. The corresponding two-dimensional CAD model of cooling hole was constructed combined with the experimental data and theoretical analysis. Numerical simulation analysis was carried out of the flow field base on the above models by using the fluid dynamics analysis software FLUENT. The influence flow velocity and flow velocity distribution on the machining accuracy and efficiency of ECM were investigated in detail. The vortex zone distribution of gas-NaNO3 mixed phase flow field and single NaNO3 solution flow field was analyzed qualitatively. The simulation results indicated that the flow velocity in the machining gap with mixed gas was significantly higher than the velocity during ECM process for cooling holes. The electrolytic products and heat were washed away completely, the electrolyte can be updated in time. Fluid vortex zone distribution was improved obviously, the flow field distribution became more uniform after mixed gas in ECM process. The machining accuracy and efficiency for cooling holes making may be improved greatly with gas mixed in electrolyte NaNO3.

Numerical Simulation and Experimental Verification of a Vertical Jet in Swirling Cross-Flow

2012 ◽  
Vol 235 ◽  
pp. 90-95
Author(s):  
Shun Li Kou ◽  
Guo Neng Li
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Flow Velocity ◽  
Velocity Ratio ◽  
Cross Flow ◽  
Tunable Laser ◽  
Simulation Method ◽  
Numerical Results ◽  
Cross Flow Velocity ◽  
Vertical Jet

In order to investigate the bending and mixing characteristics in a vertical jet issuing into a swirling cross-flow, large eddy simulation method was employed to simulate the flow field of a jet in swirling cross-flow. Several jet to cross-flow velocity ratios (r=15, 30, 60) were investigated. The numerical results were compared to the experimental data measured from a phase tunable laser and CCD system. The Reynolds number Re based on the characteristic length of the cross-flow tunnel and the jet velocity lies between 22,537 and 90,146. Numerical results showed that the penetration depth of the vertical jet maintains nearly unchanged when the jet to cross-flow velocity ratio is large enough (r>30), which agreed well with the experimental data and was different from the flow field of jet in straight cross-flow. On the other hand, the case of r=60 obtained largest spread width, and the spread width maintains relatively large in a large penetration zone, which is consist with the experimental finding.

Spatial structural characteristics of a combustion flow field in an ethylene-fueled supersonic combustor with a rear-wall-expansion cavity

2020 ◽  
Vol 34 (18) ◽  
pp. 2050208
Author(s):  
Guang-Xin Li ◽  
Ming-Bo Sun ◽  
Yi-Xin Yang ◽  
Tai-Yu Wang ◽  
Yuan Liu
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Heat Release ◽  
Shear Layer ◽  
Structural Characteristics ◽  
Wall Region ◽  
Rear Wall ◽  
Reaction Heat ◽  
Combustion Heat ◽  
Combustion Flow

A hybrid large eddy simulation (LES)/assumed subgrid probability density function (PDF) closure model was employed to investigate the structural characteristics of the combustion flow field in an ethylene-fueled supersonic combustor with a rear-wall-expansion cavity. The wall pressure distribution from numerical simulation was compared with experimental data, and the numerical results are in good agreement with the experimental data. The spatial distribution characteristics of combustion heat release in the flow field are obtained from the simulation results. The reaction heat release zone is mainly distributed in the cavity. The cavity shear layer forms a concentrated reaction zone that produces a large amount of chemical heat release, thus further maintaining local stable combustion and forming a flame base. The front part of the cavity shear layer has the highest temperature in the whole flow field. There is still excess fuel reaching the cavity rear wall and producing a certain intensity of reaction. In addition, a dispersed small flame intermittently forms in the downstream near-wall region. The premixed combustion mode dominates the cavity recirculation zone, while the combustion in the downstream region evidently shows a non-premixed mode.

Flow Field and Hot Streak Migration Through High Pressure Cooled Vanes With Representative Lean Burn Combustor Outflow

2018 ◽  
Author(s):  
T. Bacci ◽  
T. Lenzi ◽  
A. Picchi ◽  
L. Mazzei ◽  
B. Facchini
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Flow Field ◽  
Fuel Injection ◽  
Leading Edge ◽  
Flame Stabilization ◽  
Lean Burn ◽  
Aero Engine ◽  
University Of Florence ◽  
Hot Streak

Modern lean burn aero-engine combustors make use of relevant swirl degrees for flame stabilization. Moreover important temperature distortions are generated, in tangential and radial directions, due to discrete fuel injection and liner cooling flows respectively. At the same time, more efficient devices are employed for liner cooling and a less intense mixing with the mainstream occurs. As a result, aggressive swirl fields, high turbulence intensities and strong hot streaks are achieved at the turbine inlet. In order to understand combustor-turbine flow field interactions, it is mandatory to collect reliable experimental data at representative flow conditions. While the separated effects of temperature, swirl and turbulence on the first turbine stage have been widely investigated, reduced experimental data is available when it comes to consider all these factors together. In this perspective, an annular three-sector combustor simulator with fully cooled high pressure vanes has been designed and installed at the THT Lab of University of Florence. The test rig is equipped with three axial swirlers, effusion cooled liners and six film cooled high pressure vanes passages, for a vortex-to-vane count ratio of 1:2. The relative clocking position between swirlers and vanes has been chosen in order to have the leading edge of the central NGV aligned with the central swirler. In order to generate representative conditions, a heated mainstream passes though the axial swirlers of the combustor simulator, while the effusion cooled liners are fed by air at ambient temperature. The resulting flow field exiting from the combustor simulator and approaching the cooled vane can be considered representative of a modern Lean Burn aero engine combustor with swirl angles above ±50°, turbulence intensities up to about 28% and maximum-to-minimum temperature ratio of about 1.25. With the final aim of investigating the hot streaks evolution through the cooled high pressure vane, the mean aerothermal field (temperature, pressure and velocity fields) has been evaluated by means of a five hole probe equipped with a thermocouple and traversed upstream and downstream of the NGV cascade.

Numerical Study of a Dump Diffuser Flow Field in a Short Annular Combustor

1985 ◽  
Author(s):  
Hu Zhiben ◽  
Hua Guangshi
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Computer Program ◽  
Steady Flow ◽  
Numerical Study ◽  
Two Dimensional ◽  
Calculation Domain ◽  
Diffuser Flow ◽  
Annular Combustor ◽  
Relaxation Factors

A computer program for solving the two-dimensional steady flow field of the dump diffuser is made based on the streamtube method and SIMPLE (Semi–Implicit Method for Pressure linked Equations) algorithm. Some concrete measures or improvements are developed to treat the irregularly shaped calculation domain, the inlet distribution of k and ε to use the variable relaxation factors. The flow field in a short dump diffuser model with pre–diffuser and blind flame tube is calculated with the program. The calculated results agree well with the experimental data.

Analysis of Gas Entrainment Phenomenon From Free Liquid Surface for a Sodium-Cooled Fast Reactor Design: Validation of Velocity Profile and Strouhal Number in a Flow Field

2020 ◽  
Author(s):  
Mao Uchida ◽  
Moe Hirakawa ◽  
Aaru Sano ◽  
Keisuke Inoue ◽  
Takaaki Sakai ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Flow Velocity ◽  
Liquid Surface ◽  
Velocity Profiles ◽  
Reactor Vessel ◽  
Flow Channel ◽  
Wake Flow ◽  
Gas Entrainment ◽  
Piv Method

Abstract Gas entrainment (GE) from cover gas, which is an inert gas to cover sodium coolant in a reactor vessel, is one of key issue for Sodium-cooled fast reactors (SFRs) design to prevent unexpected effects to core reactivity. In this research series, evaluation method has been investigated for surface dimple depth growth of unstable drifting vortex dimples on the liquid surface in the reactor vessel. By using a computational fluid dynamics (CFD) code, analyses have been conducted to estimate the drifting vortex on water experiments in a circulating water tunnel. The unstable drifting flow vortexes on the water surface were generated as wake vortexes behind a plate obstacle. Downward flow velocity was induced by bottom slit flow pass along the flow channel. In the previous study, the onset conditions of the gas entrainment were evaluated based on existing non-dimensional numbers method by using the STREAM-VIEWER code. However, the CFD predication accuracy of the detail flow field itself was not clear especially for vortex frequency in the wake flow and detail velocity profiles in the flow channel. In this study, to clarify the accuracy of CFD analysis, Strouhal numbers of vortex frequency and detail flow velocity profiles were compared with experimental data which were measured by Particle Image Velocimetry (PIV) method. As the results, the Strouhal numbers of the vortex frequency behind the plate obstacle reasonably agreed with experimental data. Prediction accuracy for the velocity profiles in the flow channel were also confirmed by comparisons with measured data by the PIV method.

scholarly journals Spectroscopic Techniques versus Pitot Tube for the Measurement of Flow Velocity in Narrow Ducts

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7349
Author(s):  
Francesco D’Amato ◽  
Silvia Viciani ◽  
Alessio Montori ◽  
Marco Barucci ◽  
Carmen Morreale ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Velocity ◽  
Pitot Tube ◽  
Optical Measurements ◽  
Trace Gas ◽  
Dual Function ◽  
Spectroscopic Techniques ◽  
Gas Composition ◽  
Flow Conditions ◽  
Theoretical Simulation

In order to assess the limits and applicability of Pitot tubes for the measurement of flow velocity in narrow ducts, e.g., biomass burning plants, an optical, dual function device was implemented. This sensor, based on spectroscopic techniques, targets a trace gas, injected inside the stack either in bursts, or continuously, so performing transit time or dilution measurements. A comparison of the two optical techniques with respect to Pitot readings was carried out in different flow conditions (speed, temperature, gas composition). The results of the two optical measurements are in agreement with each other and fit quite well the theoretical simulation of the flow field, while the results of the Pitot measurements show a remarkable dependence on position and inclination of the Pitot tube with respect to the duct axis. The implications for the metrology of small combustors’ emissions are outlined.

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