Kai Zhang, Aymeric Lamorlette. An extensive numerical study of the burning dynamics of wildland fuel using proposed configuration space. International Journal of Heat and Mass Transfer, 2020, 160, pp.120174. ⟨10.1016/j.ijheatmasstransfer.2020.120174⟩. ⟨hal-02960139⟩ Plus de détails...
Physics-based flame models capable of predicting small-scale fire behaviors reduce computational power needed for predicting fires of large- and giga-scale. However, classical model correlations are often developed for 'free fires' without considering vegetation around. These models may result in inaccurate fire modeling due to wrong 'prior' flame shape estimated from theta similar to wind speed. To overcome this defect, three-dimensional small-scale fires with fireline intensity of 100 KW/m are numerically simulated using large eddy simulation. Fire behaviors such as flame tilt angle and heat transfer mechanisms are extensively studied using a newly proposed configuration space {N-C, CdLAI}. The former one represents the ratio between fire to wind power, and the latter one considering the vegetation effect is for the first time introduced in flame models. Using the configuration space, two model correlations for flame tilt angle and radiative heat power reaching the unburnt fuels are proposed. The flame tilt angle theta is directly related to CdLAI (C-d alpha(s)sigma H-s(F)/2), while inversely related to N-C (2gI/ rho 0C(p,0)T(0)U(0)(3)), in contrast to the model proposed for radiative heat power. Comparisons with several classical models evidenced the capability of new flame models in predicting both free and non-free fires. The limits of the validity of the newly proposed models are also discussed.
Kai Zhang, Aymeric Lamorlette. An extensive numerical study of the burning dynamics of wildland fuel using proposed configuration space. International Journal of Heat and Mass Transfer, 2020, 160, pp.120174. ⟨10.1016/j.ijheatmasstransfer.2020.120174⟩. ⟨hal-02960139⟩
Journal: International Journal of Heat and Mass Transfer
Kai Zhang, Salman Verma, Arnaud Trouvé, Aymeric Lamorlette. A study of the canopy effect on fire regime transition using an objectively defined Byram convective number. Fire Safety Journal, Elsevier, 2020, 112, pp.102950. ⟨10.1016/j.firesaf.2020.102950⟩. ⟨hal-02469260⟩ Plus de détails...
Kai Zhang, Salman Verma, Arnaud Trouvé, Aymeric Lamorlette. A study of the canopy effect on fire regime transition using an objectively defined Byram convective number. Fire Safety Journal, Elsevier, 2020, 112, pp.102950. ⟨10.1016/j.firesaf.2020.102950⟩. ⟨hal-02469260⟩
Kai Zhang, Aymeric Lamorlette. An extensive numerical study of the burning dynamics of wildland fuel using proposed configuration space. International Journal of Heat and Mass Transfer, 2020, 160, pp.120174. ⟨10.1016/j.ijheatmasstransfer.2020.120174⟩. ⟨hal-03232086⟩ Plus de détails...
Physics-based flame models capable of predicting small-scale fire behaviors reduce computational power needed for predicting fires of large- and giga-scale. However, classical model correlations are often developed for 'free fires' without considering vegetation around. These models may result in inaccurate fire modeling due to wrong 'prior' flame shape estimated from theta similar to wind speed. To overcome this defect, three-dimensional small-scale fires with fireline intensity of 100 KW/m are numerically simulated using large eddy simulation. Fire behaviors such as flame tilt angle and heat transfer mechanisms are extensively studied using a newly proposed configuration space {N-C, CdLAI}. The former one represents the ratio between fire to wind power, and the latter one considering the vegetation effect is for the first time introduced in flame models. Using the configuration space, two model correlations for flame tilt angle and radiative heat power reaching the unburnt fuels are proposed. The flame tilt angle theta is directly related to CdLAI (C-d alpha(s)sigma H-s(F)/2), while inversely related to N-C (2gI/ rho 0C(p,0)T(0)U(0)(3)), in contrast to the model proposed for radiative heat power. Comparisons with several classical models evidenced the capability of new flame models in predicting both free and non-free fires. The limits of the validity of the newly proposed models are also discussed.
Kai Zhang, Aymeric Lamorlette. An extensive numerical study of the burning dynamics of wildland fuel using proposed configuration space. International Journal of Heat and Mass Transfer, 2020, 160, pp.120174. ⟨10.1016/j.ijheatmasstransfer.2020.120174⟩. ⟨hal-03232086⟩
Journal: International Journal of Heat and Mass Transfer
T. Dupuy, T. Prusek, F. Oukacine, M. Lacroix, A. Kaiss, et al.. Fractal description of fouling deposits in boiling heat transfer modelling. International Journal of Heat and Mass Transfer, Elsevier, 2019, 145, pp.118722. ⟨10.1016/j.ijheatmasstransfer.2019.118722⟩. ⟨hal-02467974⟩ Plus de détails...
A novel methodology is developed for predicting the thermal impact of fouling in Steam Generators (SG). The originality of this methodology is to resort to fractal and statistical theories to depict the porous structure of the deposits. The proposed Statistical Fractal methodology (SF) accounts for the heat transfer driven by the liquid-vapor phase change inside the deposits. It simulates the complex intricate networks of sinuous open pores of different scales, with liquid inflows (capillaries) and vapor outflows (steam-chimneys). The multi-layered representation of fouling deposits allows to mimic aging mechanisms such as densification which occur during SG operation. The SF predictions are consistent with experimental data. The deposit thickness and the profile of porosity are found to be the most influential fouling properties on the heat exchange. The methodology is capable to simulate the experimentally observed heat transfer enhancement for thin and porous deposit as well as the heat exchange decline for thick and dense deposit.
T. Dupuy, T. Prusek, F. Oukacine, M. Lacroix, A. Kaiss, et al.. Fractal description of fouling deposits in boiling heat transfer modelling. International Journal of Heat and Mass Transfer, Elsevier, 2019, 145, pp.118722. ⟨10.1016/j.ijheatmasstransfer.2019.118722⟩. ⟨hal-02467974⟩
Journal: International Journal of Heat and Mass Transfer
Eric Serre, Sandrine Hugues, Emilia Crespo del Arco, Anthony Randriamampianina, Patrick Bontoux. Axisymmetric and three-dimensional instabilities in an Ekman boundary layer flow. International Journal of Heat and Fluid Flow, 2001, 22 (1), pp.82-93. ⟨hal-01023080⟩ Plus de détails...
Eric Serre, Sandrine Hugues, Emilia Crespo del Arco, Anthony Randriamampianina, Patrick Bontoux. Axisymmetric and three-dimensional instabilities in an Ekman boundary layer flow. International Journal of Heat and Fluid Flow, 2001, 22 (1), pp.82-93. ⟨hal-01023080⟩
Journal: International Journal of Heat and Fluid Flow
