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Wyszukujesz frazę "Stempka, J." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Impact of subgrid modelling and numerical method on autoignition simulation of two-phase flow
Autorzy:
Stempka, J.
Powiązania:
https://bibliotekanauki.pl/articles/240563.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
discretization schemes
convective term
WENO
TVD
spray combustion
człon konwekcyjny
spalanie
Opis:
The present work focuses on analyses of the autoignition delay time predicted by the large eddy simulation (LES) method by applying different subgrid scales (SGS) models and two different discretization schemes. The analysed flow configuration is a two-phase chemically reacting turbulent flow with monodispersed evaporating fuel droplets. The impact of numerical procedure is investigated in a 3D flow domain with a temporally evolving mixing layer that constituted between the streams of fuel and oxidizer that moved in opposite directions. The upper stream of cold gas carries a dispersed fuel spray (ethanol at 300 K). The lower stream is a hot air at 1000 K. Three commonly used in LES, SGS models are investigated, namely: classical Smagorinsky model, model proposed by Vreman and the σ-model proposed by Nicoud. Additionally, the impact of two discretization schemes, i.e., total variation diminishing (TVD) and weighted essentially nonoscillatory (WENO) is analysed. The analysis shows that SGS model and discretization scheme can play a crucial role in the predictions of the autoignition time. It is observed that for TVD scheme the impact of SGS model is rather small. On the contrary, when the WENO scheme is applied the results are much more dependent on the SGS model.
Źródło:
Archives of Thermodynamics; 2018, 39, 2; 55-72
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of a discretization scheme on an autoignition time in LES of a reacting droplet-laden mixing layer
Autorzy:
Stempka, J.
Kuban, L.
Tyliszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/38621390.pdf
Data publikacji:
2021
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
autoignition process
two-phase flow
mixing layer
Opis:
We analyse an autoignition process in a two-phase flow in a temporally evolving mixing layer formed between streams of a cold liquid fuel (heptane at 300 K) and a hot oxidizer (air at 1000 K) flowing in opposite directions. We focus on the influence of a discretization method on the prediction of the autoignition time and evolution of the flame in its early development phase. We use a high-order code based on the 6th order compact difference method for the Navier–Stokes and continuity equations combined with the 2nd order Total Variation Diminishing (TVD) and 5th order Weighted Essentially Non-Oscillatory (WENO) schemes applied for the discretization of the advection terms in the scalar transport equations. The obtained results show that the autoignition time is more dependent on the discretization method than on the flow initial conditions, i.e., the Reynolds number and the initial turbulence intensity. In terms of mean values, the autoignition occurs approximately 15% earlier when the TVD scheme is used. In this case, the ignition phase characterizes a sharp peak in the temporal evolution of the maximum temperature. The observed differences are attributed to a more dissipative character of the TVD scheme. Its usage leads to a higher mean level of the fuel in the gaseous form and a smoother distribution of species resulting in a lower level of the scalar dissipation rate, which facilitates the autoignition process.
Źródło:
Archives of Mechanics; 2021, 73, 2; 153-174
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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