🎉 I’m happy to share our latest work just published in Fuel, titled: “Prediction of flammable range of benzene/N₂/O₂/H₂O mixtures using detailed kinetics”
The study presents a comprehensive kinetic modeling approach for predicting the flammable limits (LFL and UFL) of benzene mixtures, with particular attention to the effects of inert gas dilution (Nâ‚‚, Hâ‚‚O), pressure, and temperature.
A freely-propagating flame configuration is used to determine the flammability limits, with radiation effects modeled through the optically thin approximation, and a detailed soot sub-mechanism included for accurate treatment of rich and ultra-rich flames.
We are especially proud that OpenSMOKE++ was used to perform all the kinetic simulations and flammability limit calculations. Thanks to its flexibility and robustness, we were able to integrate a skeletal mechanism with 136 species and nearly 5000 reactions—including a soot sub-model based on the discrete sectional approach—into the flame solver, enabling accurate and efficient predictions even in challenging ultra-rich regimes.
This work not only provides a powerful tool for interpreting benzene flammability data—especially the highly uncertain UFL—but also lays the foundation for extending the same methodology to other fuels, unconventional oxidizers, and diluents.
🔥 Explore the full paper and model here: https://www.sciencedirect.com/science/article/pii/S0016236124011116
Frassoldati, A., Hamadi, A., Stagni, A., Nobili, A., Cuoci, A., Faravelli, T., Comandini, A. and Chaumeix, N., 2024. Prediction of flammable range of benzene/N2/O2/H2O mixtures using detailed kinetics. Fuel, 371, p.131963, DOI: https://doi.org/10.1016/j.fuel.2024.131963
Abstract
This research introduces an innovative approach to predict benzene Lower and Upper Flammability Limits (LFL and UFL). The focus of this study is on predicting the flammable range of benzene/air/steam mixtures utilizing a freely-propagating flame method, incorporating an optically-thin approximation to model soot radiation. The investigation delves into the consequences of dilution by inert gases (N2 and steam), along with the impacts of pressure and initial temperature. Soot is recognized as essential not only for its role in flame chemistry under rich conditions but also for its influence on radiation, thereby affecting the flammable region of hydrocarbons especially at higher temperatures and pressures.
To address the significant formation of soot during benzene combustion near the UFL, the study integrates the kinetic model for benzene combustion with a recently developed soot mechanism based on the discrete sectional method, which has been validated extensively against a large database of sooting flames, encompassing various hydrocarbons, including benzene. To limit the computational effort associated with predicting flammability limits, a skeletal version (with 136 species and 4788 reactions) of the overall kinetic model covering benzene combustion and soot formation is developed and validated in this work.
The kinetic model was first validated against new and existing benzene flame speed data at different pressures and initial temperatures. Then it was used to investigate the flammable range. The model predictions align remarkably well with the available experimental data in the literature for the LFL, for the effect of dilution with inert gases, and with some experimental measurements for the UFL. An extensive review of these experimental data revealed significant uncertainty in characterizing benzene’s UFL experimentally, both in terms of absolute value and effect of initial temperature. The comprehensive model predictions provide valuable insights, enabling differentiation among various UFL datasets for benzene.
