Search

Your search keyword '"Faravelli, Tiziano"' showing total 684 results
Start Over Author "Faravelli, Tiziano"
684 results on '"Faravelli, Tiziano"'

19. Interface-resolved simulation of the evaporation and combustion of a fuel droplet suspended in normal gravity

Author

Saufi, Abd Essamade, Frassoldati, Alessio, Faravelli, Tiziano, and Cuoci, Alberto

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

An interface-resolved simulation of the combustion of a fuel droplet suspended in normal gravity is presented in this work, followed by an extensive analysis on the physical aspects involved. The modeling is based on DropletSMOKE++, a multiphase solver developed for the modeling of droplet vaporization and combustion in convective conditions. A wide range of phenomena can be described by the model, including the interface advection, the phase-change, the combustion chemistry, non-ideal thermodynamics and multicomponent mixtures. To our knowledge, this is the most detailed simulation performed on this configuration, providing a useful theoretical and numerical support for the experimental activity on this field. A recent experimental work is used as a reference, in which a methanol droplet is suspended on a quartz fiber and ignited at different oxygen concentrations. The numerical analysis offers a detailed insight into the physics of the problem and a satisfactory agreement with the experiments in terms of diameter decay, radial temperature profiles and sensitivity to the oxygen concentration. The vaporization rate is affected by the thermal conduction from the fiber, due to the high temperatures involved. Moreover, the fiber perturbs the flame itself, providing quenching at its surface. The combustion physics is compared to the one predicted at zero-gravity, evidencing a lower standoff-ratio, a higher flame temperature and an intense internal circulation. The distribution of the species around the droplet shows (i) a local accumulation of intermediate oxidation products at the fiber surface and (ii) water absorption in the liquid phase, affecting the vaporization rate.

Published
2020
Full Text
View/download PDF

20. DropletSMOKE++: a comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

Author

Saufi, Abd Essamade, Frassoldati, Alessio, Cuoci, Alberto, and Faravelli, Tiziano

Subjects
Computer Science - Computational Engineering, Finance, and Science, Physics - Computational Physics
Abstract

This paper aims at presenting the DropletSMOKE++ solver, a comprehensive multidimensional computational framework for the evaporation of fuel droplets, under the influence of a gravity field and an external fluid flow. The Volume Of Fluid (VOF) methodology is adopted to dynamically track the interface, coupled with the solution of energy and species equations. The evaporation rate is directly evaluated based on the vapor concentration gradient at the phase boundary, with no need of semi-empirical evaporation sub-models. The strong surface tension forces often prevent to model small droplets evaporation, because of the presence of parasitic currents. In this work we by-pass the problem, eliminating surface tension and introducing a centripetal force toward the center of the droplet. This expedient represents a major novelty of this work, which allows to numerically hang a droplet on a fiber in normal gravity conditions without modeling surface tension. Parasitic currents are completely suppressed, allowing to accurately model the evaporation process whatever the droplet size. DropletSMOKE++ shows an excellent agreement with the experimental data in a wide range of operating conditions, for various fuels and initial droplet diameters, both in natural and forced convection. The comparison with the same cases modeled in microgravity conditions highlights the impact of an external fluid flow on the evaporation mechanism, especially at high pressures. Non-ideal thermodynamics for phase-equilibrium is included to correctly capture evaporation rates at high pressures, otherwise not well predicted by an ideal gas assumption. Finally, the presence of flow circulation in the liquid phase is discussed, as well as its influence on the internal temperature field. DropletSMOKE++ will be released as an open-source code, open to contributions from the scientific community.

Published
2020
Full Text
View/download PDF

27. Velocity Spectra and Model Spectrum in Non-Premixed Jet Flames

Author

Shamooni, Ali, Cuoci, Alberto, Faravelli, Tiziano, and Sadiki, Amsini

Subjects
Physics - Fluid Dynamics
Abstract

In this contribution, velocity and its dissipation spectra in turbulent non-premixed jet flames are investigated by using two Direct Numerical Simulation (DNS) databases of temporally evolving jets with different bulk jet Reynolds numbers. In the DNS differential diffusion and flame dynamics effects have been accounted for and the flames experience high levels of extinction followed by re-ignition. It turns out that the spectra extracted from different statistically homogeneous planes across the jets and selected times corresponding to various occurring flame regimes (extinction and re-ignition phases) collapse reasonably when normalized by Favre averaged turbulent quantities. Especially (1) in the inertial range, the $\kappa^{-5/3}$ power law is observed with the constant of proportionality of $C_{K}=2.3$. (2) In the dissipation range $\exp(\beta\kappa)$ scaling exists with $\beta=7.2$ (instead of $\beta=5.2$). (3) The location of the peak of the normalized 1D dissipation spectra is in a lower normalized waver number ($\approx 0.08$) compared to the peak of non-reactive model spectrum ($\approx 0.11$). (4) Finally, an adapted 3D dissipation model spectrum proposed which peaks at a normalized waver number $\approx 0.19$ (instead of $\approx 0.26$).

Published
2019

38. A new detailed kinetic model for surrogate fuels: C3MechV3.3

Author

Dong, Shijun, Wagnon, Scott W., Pratali Maffei, Luna, Kukkadapu, Goutham, Nobili, Andrea, Mao, Qian, Pelucchi, Matteo, Cai, Liming, Zhang, Kuiwen, Raju, Mandhapati, Chatterjee, Tanusree, Pitz, William J., Faravelli, Tiziano, Pitsch, Heinz, Senecal, Peter Kelly, and Curran, Henry J.

Published
2022
Full Text
View/download PDF

48. Contributors

Author

Abdelbaki, Mameri, primary, Amaduzzi, Ruggero, additional, Arghode, Vaibhav Kumar, additional, Ariemma, Giovanni Battista, additional, Azimi, Amirhossein, additional, Bagheri, Ghobad, additional, Bitala, Petr, additional, Cavaliere, Antonio, additional, Chen, Sheng, additional, Chitgarha, Fatemeh, additional, Dally, Bassam B, additional, de Joannon, Mara, additional, Doan, N.A.K., additional, Dostál, Michal, additional, Faravelli, Tiziano, additional, Frassoldati, Alessio, additional, Guo, Junjun, additional, Hosseini, Seyed Ehsan, additional, Hu, Fan, additional, Karyeyen, Serhat, additional, Klečka, Vít, additional, Klimanek, Adam, additional, Kumar, Sudarshan, additional, Li, Pengfei, additional, Liu, Hao, additional, Liu, Zhaohui, additional, Motaalegh Mahalegi, Hamed Karimi, additional, Manna, Maria Virginia, additional, Mardani, Amir, additional, Nevrlý, Václav, additional, Parente, Alessandro, additional, Pelucchi, Matteo, additional, Péquin, Arthur, additional, Ragucci, Raffaele, additional, Rahman, Zia ur, additional, Sabia, Pino, additional, Saha, Manabendra, additional, Sharma, Preetam, additional, Sharma, Saurabh, additional, Sorrentino, Giancarlo, additional, Stagni, Alessandro, additional, Su, Yaxin, additional, Tu, Yaojie, additional, Wan, Jiawei, additional, Wang, Xuebin, additional, Xu, Shunta, additional, Zelinger, Zdeněk, additional, Zhang, Yixiang, additional, and Zhao, Bingtao, additional

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results