Experimental and numerical investigation of thermo-acoustic instability in a liquid-fuel aero-engine combustor at elevated pressure: Validity of large-eddy simulation of spray combustion

2015 ◽  
Vol 162 (6) ◽  
pp. 2621-2637 ◽  
Author(s):  
Shigeru Tachibana ◽  
Kinya Saito ◽  
Takeshi Yamamoto ◽  
Mitsumasa Makida ◽  
Tomoaki Kitano ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Numerical Investigation ◽  
Liquid Fuel ◽  
Elevated Pressure ◽  
Spray Combustion ◽  
Acoustic Instability ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Aero Engine

scholarly journals Effects of ambient methanol on pollutants formation in dual-fuel spray combustion at varying ambient temperatures: A large-eddy simulation

2020 ◽  
Vol 279 ◽  
pp. 115774 ◽  
Author(s):  
Shijie Xu ◽  
Shenghui Zhong ◽  
Kar Mun Pang ◽  
Senbin Yu ◽  
Mehdi Jangi ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Fuel Spray ◽  
Spray Combustion ◽  
Dual Fuel ◽  
Ambient Temperatures ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulation Study of Flow Dynamics in a Multiswirler Model Combustor at Elevated Pressure and High Temperature

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Weijie Liu ◽  
Qian Yang ◽  
Ranran Xue ◽  
Huiru Wang
Keyword(s):  
High Temperature ◽  
Large Eddy Simulation ◽  
Elevated Pressure ◽  
Dominant Frequency ◽  
Flow Dynamics ◽  
Main Stage ◽  
Eddy Simulation ◽  
Precessing Vortex Core ◽  
Flow Interaction ◽  
Large Eddy

Large eddy simulation (LES) of nonreacting turbulent flow in a multiswirler model combustor is carried out at elevated pressure and high temperature. Flow interaction between the main stage and the pilot stage is discussed based on the time-averaged and instantaneous flowfield. Flow dynamics in the multiswirling flow are analyzed using a phase-averaged method. Proper orthogonal decomposition (POD) is used to extract dominant flow features in the multiswirling flow. Numerical results show that the main stage and the pilot stage flows interact with each other generating a complex flowfield. Flow interaction can be divided into three regions: converging region, merging region, and combined region. A precessing vortex core (PVC) is successfully captured in the pilot stage. PVC rotates with a first dominant frequency of 2756 Hz inducing asymmetric azimuthal flow instabilities in the pilot stage. POD analyses for the velocity fields also show dominant high-frequency modes (mode 1 and mode 2) in the pilot stage. However, the dominant energetic flow is damped rapidly downstream of the pilot stage such that it has a little effect on the main stage flow.

Numerical Investigation of 3-D Supersonic Jet Flows Using Large-Eddy Simulation

2012 ◽  
Vol 11 (7-8) ◽  
pp. 783-812 ◽  
Author(s):  
S.-C. Lo ◽  
K. M. Aikens ◽  
G. A. Blaisdell ◽  
A. S. Lyrintzis
Keyword(s):  
Large Eddy Simulation ◽  
Numerical Investigation ◽  
Supersonic Jet ◽  
Jet Flows ◽  
Eddy Simulation ◽  
Large Eddy

Simulating Flame Lift-Off Characteristics of Diesel and Biodiesel Fuels Using Detailed Chemical-Kinetic Mechanisms and Large Eddy Simulation Turbulence Model

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Sibendu Som ◽  
Douglas E. Longman ◽  
Zhaoyu Luo ◽  
Max Plomer ◽  
Tianfeng Lu ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Chemical Kinetic ◽  
Spray Combustion ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Kinetic Mechanisms ◽  
Lift Off ◽  
Biodiesel Fuels

Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well as Reynolds-averaged Navier–Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the renormalization group (RNG) k-ε (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 μm and 125 μm were obtained for the RANS and LES cases, respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-ε model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl nine-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.

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