Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×5.2m rectangular circulating fluidized bed riser.Using heated tracer injection,the lateral solid dispersion was determ...Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×5.2m rectangular circulating fluidized bed riser.Using heated tracer injection,the lateral solid dispersion was determined by measuring the temperature response at different lateral positions. Furthermore, a one-dimensional dispersion model,which describes the solid mixing in the dense zone,is presented.The experimental results were used to determine the lateral particle dispersion coefficient under various operating conditions. A correlation of dispersion coefficient with bed height, gas velocity,and particle size is also proposed.展开更多
The dispersion characteristics of fuel particles in the dense phase zone in circulating fluidized bed(CFB)boilers have an important influence on bed temperature distribution and pollutant emissions.However,previous re...The dispersion characteristics of fuel particles in the dense phase zone in circulating fluidized bed(CFB)boilers have an important influence on bed temperature distribution and pollutant emissions.However,previous research in literature was mostly on small-scale apparatus,whose results could not be applied directly to large-scale CFB with multiple dispersion sources.To help solve this problem,we proposed a novel method to estimate the lateral dispersion coefficient(Dx)of fuel particles under partial coal cut-off condition in a 35o MW supercritical CFB boiler based on combustion and dispersion models.Meanwhile,we carried out experiments to obtain the Dx in the range of 0.1218-0.1406 m2/s.Numerical simulations were performed and the influence of operating conditions and furnace structure on fuel dispersion characteristics was investigated,the simulation value of Dx was validated against experimental data.Results revealed that the distribution of bed temperature caused by the fuel dispersion was mainly formed by char combustion.Because of the presence of intermediate water-cooled partition wall,the mixing and dispersion of fuel and bed material particles between the left and right sides of the furnace were hindered,increasing the non-uniformity of the bed temperature near furnace front wall.展开更多
Based on the orthotropic elastic theory of rock masses, the X-ray method was used to measure the distribution of macro-residual strain energy density along a depth profile,using core samples taken from 47 large-apertu...Based on the orthotropic elastic theory of rock masses, the X-ray method was used to measure the distribution of macro-residual strain energy density along a depth profile,using core samples taken from 47 large-aperture deep boreholes in four regions of Southwest China： the Longmenshan, Anninghe, Honghe, and Xianshuihe fault zones.Then, the vertical gradients of the macro-residual strain energy density and the macroresidual strain energy contained in high-energy cuboid block segments along each fault zone were determined. The results demonstrate that the macro-residual strain energy stored at shallow levels in the rock mass in these fault zones may be partly responsible for generating many large earthquakes and may explain why the large earthquakes in this region are typically shallow.展开更多
文摘Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×5.2m rectangular circulating fluidized bed riser.Using heated tracer injection,the lateral solid dispersion was determined by measuring the temperature response at different lateral positions. Furthermore, a one-dimensional dispersion model,which describes the solid mixing in the dense zone,is presented.The experimental results were used to determine the lateral particle dispersion coefficient under various operating conditions. A correlation of dispersion coefficient with bed height, gas velocity,and particle size is also proposed.
基金supported by the National Natural Science Foundation of China(grant No.52176101).
文摘The dispersion characteristics of fuel particles in the dense phase zone in circulating fluidized bed(CFB)boilers have an important influence on bed temperature distribution and pollutant emissions.However,previous research in literature was mostly on small-scale apparatus,whose results could not be applied directly to large-scale CFB with multiple dispersion sources.To help solve this problem,we proposed a novel method to estimate the lateral dispersion coefficient(Dx)of fuel particles under partial coal cut-off condition in a 35o MW supercritical CFB boiler based on combustion and dispersion models.Meanwhile,we carried out experiments to obtain the Dx in the range of 0.1218-0.1406 m2/s.Numerical simulations were performed and the influence of operating conditions and furnace structure on fuel dispersion characteristics was investigated,the simulation value of Dx was validated against experimental data.Results revealed that the distribution of bed temperature caused by the fuel dispersion was mainly formed by char combustion.Because of the presence of intermediate water-cooled partition wall,the mixing and dispersion of fuel and bed material particles between the left and right sides of the furnace were hindered,increasing the non-uniformity of the bed temperature near furnace front wall.
基金supported by the Joint Seismology Science Foundation(85012,850708,863017,88138,91046)Old Professor Science Foundation(201041)
文摘Based on the orthotropic elastic theory of rock masses, the X-ray method was used to measure the distribution of macro-residual strain energy density along a depth profile,using core samples taken from 47 large-aperture deep boreholes in four regions of Southwest China： the Longmenshan, Anninghe, Honghe, and Xianshuihe fault zones.Then, the vertical gradients of the macro-residual strain energy density and the macroresidual strain energy contained in high-energy cuboid block segments along each fault zone were determined. The results demonstrate that the macro-residual strain energy stored at shallow levels in the rock mass in these fault zones may be partly responsible for generating many large earthquakes and may explain why the large earthquakes in this region are typically shallow.
