The Role of Ti in the Preparation of SiC/7075 Aluminum Matrix Composite

Zhang, Wen-da; Chen, Chengcheng; Xu, Hong; Che, Luchang; Guo, Cheng; Du, Zhenmin

doi:10.1007/s11595-020-2256-y

Cited by 8 publications

(9 citation statements)

References 19 publications

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“…Small oil droplets of diameter 1-3 µm are, in this case, seeded in the flow. The PIV system consists of 2×400 mJ Nd:YAG laser doubled at 532 nm operated at 10 Hz and a 2048×2048 px 2 CCD camera (Dantec Dynamics, FlowSense EO 4M). Two different optical setups are used for longitudinal and transverse measurements, with a time delay between the two laser pulses ∆t =10 µs and a pixel pitch of 27.9 px/mm in the first case and ∆t =25 µs with a pixel pitch of 40.1 px/mm in the second one.…”

Section: Methodsmentioning

confidence: 99%

“…The frequency response of premixed swirling flames submitted to flow rate modulations is a topic of high scientific and technical interest due to the problems raised by combustion instabilities in gas turbines [1][2][3]. This response is often characterized by a Flame Transfer Function (FTF) or more recently by a Flame Describing Function (FDF) when the level of flow disturbances is considered [4].…”

Section: Introductionmentioning

confidence: 99%

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Impact of swirl and bluff-body on the transfer function of premixed flames

Gatti

Gaudron

Mirat

et al. 2019

Proceedings of the Combustion Institute

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The frequency response of three lean methane/air flames submitted to flowrate perturbations is analyzed for flames featuring the same equivalence ratio and thermal power, but a different stabilization mechanism. The first flame is stabilized by a central bluff body without swirl, the second one by the same bluff body with the addition of swirl and the last one only by swirl without central insert. In the two last cases, the swirl level is roughly the same. These three flames feature different shapes and heat release distributions, but their Flame Transfer Function (FTF) feature about the same phase lag at low frequencies. The gain of the FTF also shows the same behavior for the flame stabilized by the central insert without swirl and the one fully aerodynamically stabilized by swirl. Shedding of vortical structures from the injector nozzle that grow and rollup the flame tip controls the FTF of these flames. The flame stabilized by the swirler-plus-bluff-body system features a peculiar response with a large drop of the FTF gain around a frequency at which large swirl number oscillations are observed. Velocity measurements in cold flow conditions reveal a strong reduction of the size of the vortical structures shed from the injector lip at this frequency. The flame stabilized aerodynamically only by swirl and the one stabilized by the bluff body without swirl don't exhibit any FTF gain drop at low frequencies. In the former case, large swirl number oscillations are still identified, but large vortical structures shed from the nozzle also persist at the same forcing frequency in the cold flow response. These different flame responses are found to be related to the dynamics of the internal recirculation region, which response strongly differs depending upon the mechanism adopted to stabilize the flame.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of swirl and bluff-body on the transfer function of premixed flames

Gatti

Gaudron

Mirat

et al. 2019

Proceedings of the Combustion Institute

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“…Shape memory polymer (SMP) is a kind of smart material, which can revert to the original shape from the deformed shape with the effect of outside stimulus like light [1], heat [2], electromagnetic field [3], specific ion [4] and so on. Compared with general materials and composite materials [5], SMP has excellent deformation ability, biodegradability, biocompatibility, and well manufacturing performance, so that it has wide application prospect in biomedicine [6] and aerospace [7] and electronic devices [8]. The thermally responsive SMP is one of the research hotspots because it is easy to trigger shape memory process and easy to be controlled of the deformation.…”

Section: Introductionmentioning

confidence: 99%

Constitutive model for epoxy shape memory polymer with regulable phase transition temperature

Zhao

Zheng

Zhou

et al. 2021

International Journal of Smart and Nano Materials

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The epoxy shape memory polymer (SMP) with adjustable phase transition temperature is a kind of high-performance shape memory polymer, which can change its phase transition temperature and improve its mechanical properties through the process of photo curing. An epoxy SMP constitutive model combining phase transition and viscoelasticity is established by discretizing the epoxy SMP into several glass phase units and rubbery phase units in this paper. The model includes the viscoelastic constitutive equations of glass phase units and rubber phase units, the parameter expression during shape memory process, and material parameter equation during photocuring process. And the stress relaxation behavior of epoxy SMP at different temperatures and the change of material parameters during the photo-curing process are simulated numerically, and the simulation results perform consistency with the experimental data. The model can not only relate shape memory effect and phase transformation in physics but also better characterize the viscoelastic properties of SMP and predict the shape memory response of SMP.

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“…Lean premixed combustion has the potential to achieve the emission limits dictated by stringent legislations, making this strategy desirable for many practical applications [1], e.g. gas turbines or lean burn gas engines.…”

Section: Introductionmentioning

confidence: 99%

“…gas turbines or lean burn gas engines. However, while lean mixtures ensure low emission levels, they are susceptible to low Damköhler number phenomena such as local or global extinction [1][2][3]. The stabilization and blow-off mechanisms of such flames are dictated by complex multi-scale interactions between turbulence and chemical kinetics that influence the flame inner structure depending on the aerothermo-chemical properties of the flow.…”

Section: Introductionmentioning

confidence: 99%

A LES-CMC formulation for premixed flames including differential diffusion

Farrace

Chung

Bolla

et al. 2018

Combustion Theory and Modelling

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A finite volume Large Eddy Simulation-Conditional Moment Closure (LES-CMC) numerical framework for premixed combustion developed in a previous study [Farrace et al., Proc. Combust. Inst. 36 (2017)], has been extended to account for differential diffusion. The non-unity Lewis number CMC transport equation has an additional convective term in sample space proportional to the conditional diffusion of the progress variable, that in turn accounts for diffusion normal to the flame front and curvature-induced effects. Planar laminar simulations are first performed using a spatiallyhomogeneous non-unity Lewis number CMC formulation and validated against physical-space fully-resolved reference solutions. The same CMC formulation is subsequently used to numerically investigate the effects of curvature for laminar flames having different effective Lewis numbers: a lean methane-air flame with Le eff = 0.99 and a lean hydrogen-air flame with Le eff = 0.33. Results suggest that curvature does not affect the conditional heat release if the effective Lewis number tends to unity, so that curvature-induced transport may be neglected. Finally, the effect of turbulence on the flame structure is qualitatively analysed using LES-CMC simulations with and without differential diffusion for a turbulent premixed bluff body methane-air flame exhibiting local extinction behaviour. Overall, both the unity and the non-unity computations predict the characteristic "M-shaped" flame observed experimentally, although some minor differences are identified. The findings suggest that for the high Karlovitz number (from 1 to 10) flame considered, turbulent mixing within the flame weakens the differential transport contribution by reducing the conditional scalar dissipation rate and accordingly the conditional diffusion of the progress variable.

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The Role of Ti in the Preparation of SiC/7075 Aluminum Matrix Composite

Cited by 8 publications

References 19 publications

Impact of swirl and bluff-body on the transfer function of premixed flames

Impact of swirl and bluff-body on the transfer function of premixed flames

Constitutive model for epoxy shape memory polymer with regulable phase transition temperature

A LES-CMC formulation for premixed flames including differential diffusion

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