Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such lar...Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such large spaces.The turbulent Schmidt number(Sc_(t))concept has typically been used in this regard,and most studies have adopted a default value.We studied the concentration distribution for sulfur hexafluoride(SF_(6))assuming different emission rates and considering the effect of Sc_(t).Then we examined the same problem for a light gas by assuming hydrogen gas(H_(2))as the contaminant.When SF_(6) was considered as the contaminant gas,a variation in the emission rate completely changed the concentration distribution.When the emission rate was low,the gravitational effect did not take place.For both low and high emission rates,an increase in S_(ct) accelerated the transport rate of SF_(6).In contrast,for H_(2) as the contaminant gas,a larger S_(ct) could induce a decrease in the H_(2) transport rate.展开更多
This paper presents a theoretical analysis of a pulsed bicomponent contaminant emission into a flee-surface wetland flow. The basic equations are for the bicomponent contaminant transport in the wetland flow under the...This paper presents a theoretical analysis of a pulsed bicomponent contaminant emission into a flee-surface wetland flow. The basic equations are for the bicomponent contaminant transport in the wetland flow under the combined action of advection, mass dispersion, and ecological reaction at the phase averaged scale. The effect of the ecological reaction is separated from the hydrodynamic effect via a set of widely used transforms. The analytical solution for the evolution of the depth-averaged concentration is rigorously derived, with a limiting case covering the known solution for the single component contaminant transport. It is found that the depth-averaged species concentration of the bicomponent contaminant can approach an equilibrium state determined by the distribution coefficient.展开更多
基金funded by the National Natural Science Foundation of China and the Machinery Industry Innovation Platform Construction Project of China Machinery Industry Federation,Grant Numbers 52378103 and 2019SA-10-07.
文摘Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such large spaces.The turbulent Schmidt number(Sc_(t))concept has typically been used in this regard,and most studies have adopted a default value.We studied the concentration distribution for sulfur hexafluoride(SF_(6))assuming different emission rates and considering the effect of Sc_(t).Then we examined the same problem for a light gas by assuming hydrogen gas(H_(2))as the contaminant.When SF_(6) was considered as the contaminant gas,a variation in the emission rate completely changed the concentration distribution.When the emission rate was low,the gravitational effect did not take place.For both low and high emission rates,an increase in S_(ct) accelerated the transport rate of SF_(6).In contrast,for H_(2) as the contaminant gas,a larger S_(ct) could induce a decrease in the H_(2) transport rate.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10972009,50939001and41271543)supported by the Special Foundation of China Institute of Water Resources and Hydropower Research(Contract No.SJ1239)
文摘This paper presents a theoretical analysis of a pulsed bicomponent contaminant emission into a flee-surface wetland flow. The basic equations are for the bicomponent contaminant transport in the wetland flow under the combined action of advection, mass dispersion, and ecological reaction at the phase averaged scale. The effect of the ecological reaction is separated from the hydrodynamic effect via a set of widely used transforms. The analytical solution for the evolution of the depth-averaged concentration is rigorously derived, with a limiting case covering the known solution for the single component contaminant transport. It is found that the depth-averaged species concentration of the bicomponent contaminant can approach an equilibrium state determined by the distribution coefficient.
