Simulation of a Single-Element Lean-Direct Injection Combustor Using a Polyhedral Mesh Derived from Hanging-Node Elements

Wey, Changlie; Liu, Nan-Suey

doi:10.2514/6.2013-739

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…Figure 1 shows the computational domain representing the region of interest, including the helical vanes and the combustion chamber. Best practices (Ajmani et al, 2013a(Ajmani et al, , 2013b(Ajmani et al, , 2013cWey and Liu, 2013) in terms of meshing and modeling guidelines for the single helical swirler were created. LES requires both time step and mesh sizes sufficiently refined to capture the energy-containing eddies.…”

Section: Computational Domain and Mesh Requirements For Large Eddy Si...mentioning

confidence: 99%

LES predictions of confinement effect on swirling flow generated by single helical axial swirler

Rajesh

Sivakumar

2022

AEAT

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Purpose For higher swirling flows (swirl > 0.5), flow confinement significantly impacts fluid flow, flame stability, flame length and heat transfer, especially when the confinement ratio is less than 9. Past numerical studies on helical axial swirler type systems are limited to non-reacting or reacting flows type Reynolds averaged Navier Stokes closure models, mostly are non-parametric studies. Effects of parametric studies like swirl angle and confinement on the unsteady flow field, either numerical or experimental, are very minimal. The purpose of this paper is to document modeling practices for a large eddy simulation (LES) type grid, predict the confinement effects of a single swirler lean direct injection (LDI) system and validate with literature data. Design/methodology/approach The first part of the paper discusses the approach followed for numerical modelling of LES with the minimum number of cells required across critical sections to capture the spectrum of turbulent energy with good accuracy. The numerical model includes all flow developing sections of the LDI swirler, right from the axial setting chamber to the exit of the flame tube, and its length is effectively modelled to match the experimental data. The computational model predicts unsteady features like vortex breakdown bubble, represented by a strong recirculation zone anchored downstream of the fuel nozzle. It is interesting to note that the LES is effective in predicting the secondary recirculation zones in the divergent section as well as at the corners of the tube wall. Findings The predictions of a single helical axial swirler with a vane tip angle of 60°, with a duct size of 2 × 2 square inches, are compared with the experimental data at several axial locations as well as with centerline data. Both mean and unsteady turbulent quantities obtained through the numerical simulations are validated with the experimental data (Cai et al., 2005). The methodology is extended to the confinements effect on mean flow characteristics. The time scale and length scale are useful parameters to get the desired results. The results show that with an increase in the confinement ratio, the recirculation length increases proportionally. A sample of three cases has been documented in this paper. Originality/value The novelty of the paper is the modelling practices (grid/unsteady models) for a parametric study of LDI are established, and the mean confinement effects are validated with experimental data. The spectrum of turbulent energies is well captured by LES, and trends are aligned with experimental data. The methodology can be extended to reacting flows also to study the effect of swirl angle, fuel injection on aerodynamics, droplet characteristics and emissions.

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Section: Computational Domain and Mesh Requirements For Large Eddy Si...mentioning

confidence: 99%

LES predictions of confinement effect on swirling flow generated by single helical axial swirler

Rajesh

Sivakumar

2022

AEAT

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Updates to Simulation of a Single-Element Lean-Direct Injection Combustor Using a Polyhedral Mesh Derived from Hanging-Node Elements

Wey

Liu

2014

52nd Aerospace Sciences Meeting

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Updates to Simulation of a Single-Element Lean-Direct Injection Combustor Using Arbitrary Polyhedral Meshes

Wey

Liu

2015

53rd AIAA Aerospace Sciences Meeting

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Simulation of a Single-Element Lean-Direct Injection Combustor Using a Polyhedral Mesh Derived from Hanging-Node Elements

Abstract: This paper summarizes the procedures of generating a polyhedral mesh derived from hanging-node elements as well as presents sample results from its application to the numerical solution of a singleelement LDI combustor using an open-source version of NCC.

Cited by 4 publications

References 2 publications

LES predictions of confinement effect on swirling flow generated by single helical axial swirler

LES predictions of confinement effect on swirling flow generated by single helical axial swirler

Updates to Simulation of a Single-Element Lean-Direct Injection Combustor Using a Polyhedral Mesh Derived from Hanging-Node Elements

Updates to Simulation of a Single-Element Lean-Direct Injection Combustor Using Arbitrary Polyhedral Meshes

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