Direct numerical simulations of gas-solid flow with random arrangements of particles : assessment of drag forces in 2D flow
Zaynetdinov, Konstantin (2020)
Diplomityö
2020
School of Energy Systems, Energiatekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2020120899848
https://urn.fi/URN:NBN:fi-fe2020120899848
Tiivistelmä
Many processes in engineering are based on gas-solid flows. The momentum exchange between the gas and the solid phases is described by drag models, which play an essential role in modelling of gas-solid flows. Many drag models can be found in literature, however, there is no consensus among the researches on which model gives the most accurate prediction to the drag force.
In this Master’s thesis, direct numerical simulations of gas flow past random configurations of static monodisperse particles are performed. Five different arrangements of particles are generated for each of 48 combinations of the particle diameter, the solid volume fraction and the superficial velocity of the gas phase. Then the flow is simulated in Ansys FLUENT for each case, and the drag force exerted on particles is calculated, as well as the interphase momentum exchange coefficient and the normalized drag force.
The results of the simulations showed that there is a significant deviation between the values of the drag force obtained for the same set of parameters but different arrangements of particles, which is explained by the channelling effect. The comparison of 13 drag models with the simulation data showed that the Huilin-Gidaspow model and the Beetstra et al. model have an average deviation of 14.9% and 19.5%, respectively. This deviation is smaller than that of other drag models but still large enough to conclude that further research is required in this field to derive a new, more accurate correlation.
In this Master’s thesis, direct numerical simulations of gas flow past random configurations of static monodisperse particles are performed. Five different arrangements of particles are generated for each of 48 combinations of the particle diameter, the solid volume fraction and the superficial velocity of the gas phase. Then the flow is simulated in Ansys FLUENT for each case, and the drag force exerted on particles is calculated, as well as the interphase momentum exchange coefficient and the normalized drag force.
The results of the simulations showed that there is a significant deviation between the values of the drag force obtained for the same set of parameters but different arrangements of particles, which is explained by the channelling effect. The comparison of 13 drag models with the simulation data showed that the Huilin-Gidaspow model and the Beetstra et al. model have an average deviation of 14.9% and 19.5%, respectively. This deviation is smaller than that of other drag models but still large enough to conclude that further research is required in this field to derive a new, more accurate correlation.