The research on Constructed Soil Rapid Infiltration(CSRI) system is in its infancy at home and abroad.There are several details about the mechanism and application of CSRI system needed to be further studied.A major l...The research on Constructed Soil Rapid Infiltration(CSRI) system is in its infancy at home and abroad.There are several details about the mechanism and application of CSRI system needed to be further studied.A major limitation in the current research is the absence of degradation dynamics of pollutants,and the height of filtration bed in CSRI system currently determined by empirical judgment lacks accuracy and logicality.To solve these two prob-lems,the soil column of CSRI system was utilized to treat domestic wastewater,meanwhile,the NH3-N degradation dynamics were studied according to the Monod equation,the research of Mann A T and the NH3-N degradation law.Then the mathematical model of filtration bed height was built based on NH3-N degradation dynamics equation in the soil column.It has been proven that within a limited range this model can calculate the appropriate height of filtration bed accurately in order to optimize technological parameters of hydraulic load and the concentration of influent NH3-N,improving the effluent quality of CSRI system.展开更多
Characterizing the hydrodynamics of a fluidized bed flotation column is essential for understanding the behavior of this multiphase flow system.Bed pressure fluctuations and phase hold-ups are two of these key charact...Characterizing the hydrodynamics of a fluidized bed flotation column is essential for understanding the behavior of this multiphase flow system.Bed pressure fluctuations and phase hold-ups are two of these key characteristics.Static bed height effects on these two key characteristics were comprehensively studied using experimental and statistical analysis operating for different flow regimes.And three different bed height-to-diameter ratios(H/D=1.0,1.5,and 2.0)were investigated.The time series signals of pressure fluctuation were recorded via a pressure transducer,then analyzed through time and frequency domain methods.Cross-sectional and radial combined gas and solid hold-ups distribution were detected through the electrical resistance tomography under different H/D ratios.Results indicated that the key parameters of bed pressure fluctuation signals and gas-solid hold-up distributions are significantly affected by the change in static bed height,which can be explained by differences in bubble dynamics and particle movement behaviors.展开更多
To study olefin reduction by using an auxiliary reactor for FCC naphtha upgrading, a large-scale cold model of a riser-bed coupled to an upper fluidized bed was established. The effect of static bed height in the uppe...To study olefin reduction by using an auxiliary reactor for FCC naphtha upgrading, a large-scale cold model of a riser-bed coupled to an upper fluidized bed was established. The effect of static bed height in the upper fluidized bed on narticle flow behavior in the lower riser was investigated experimentally. A restriction index of solids holdup was used to evaluate quantitatively the restrictive effect of the upper fluidized bed. Experimental results show that, under the restrictive effect of the upper fluidized bed, the riser could be divided into three regions in the longitudinal direction： accelerating, fully developed and restriction. The axial distribution of solids holdup in the riser is characterized by large solids holdup in the top and bottom sections and small solids holdup in the middle section. Overall solids holdup increased with increasing static bed height in the upper fluidized bed, while particle velocity decreased. Such restrictive effect of the upper fluidized bed could extend from the middle and top sections to the whole riser volume when riser outlet resistance is increased, which increases with increasing static bed height in the upper fluidized bed. The upper bed exerts the strongest restriction on the area close to the riser outlet.展开更多
The impact of temperature and particle size on minimumfluidizing velocity was studied and analyzed in a small pilot scale of bubbling fluidized bed reactor.This study was devoted to providing some data about fluidizat...The impact of temperature and particle size on minimumfluidizing velocity was studied and analyzed in a small pilot scale of bubbling fluidized bed reactor.This study was devoted to providing some data about fluidization to the literature under high temperature conditions.The experiments were carried out to evaluate the minimum fluidizing velocity over a vast range of temperature levels from 20℃ to 850℃ using silica sand with a particle size of 300-425μm,425-500μm,500-600μm,and 600-710μm.Furthermore,the variation in the minimumfluidized voidage was determined experimentally at the same conditions.The experimental data revealed that the Umf directly varied with particle size and inversely with temperature,whileεmf increases slightly with temperature based on the measurements of height at incipient fluidization.However,for all particle sizes used in this test,temperatures above 700℃ has a marginal effect on Umf.The results were compared with many empirical equations,and it was found that the experimental result is still in an acceptable range of empirical equations used.In which,our findings are not well predicted by the widely accepted correlations reported in the literature.Therefore,a new predicted equation has been developed that also accounts for the affecting of mean particle size in addition to other parameters.A good mean relative deviation of 5.473% between the experimental data and the predicted values was estimated from the correlation of the effective dimensionless group.Furthermore,the experimental work revealed that the minimum fluidizing velocity was not affected by the height of the bed even at high temperature.展开更多
The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes...The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.展开更多
Fault-related parameters are critical for studying tectonic evolution, deformation character- istics, active tectonism, and seismic hazards. A new method of calculating reverse-fault- related parameters has been devel...Fault-related parameters are critical for studying tectonic evolution, deformation character- istics, active tectonism, and seismic hazards. A new method of calculating reverse-fault- related parameters has been developed, which uses systematic analysis of the geometrical characteristics of normal and reverse scarps of reverse faults together with measurements of topographic profiles and fault bedding. The results show that the most suitable method of calculating fault parameters heavily relies on the specific type of fault scarp. For a reverse scarp, the size of the vertical displacement （VD） of the fault, the vertical separation （VS） of the hanging wall and the footwall, and the fault scarp height （SH）how the relationship VD ≥VS ≥ SH; conversely, for normal scarps, VD ≤ VS ≤ SH. The theoretical equations were used to study fault deformation in the Southwest Tianshan Mountain foreland basin. The results showed that, for every fault, VD ≥ VS ≥SH, which is consistent with our predicted relationship. This finding demonstrates that this method is suitable to explore structural information of reverse faults. In the study area, the vertical displacement is 1.4 times the horizontal displacement, suggesting that fiexural-slip faults may play an important role in transferring local deformation from horizontal shortening to vertical uplift. Therefore, one of the most important steps in correct calculation of reverse-fault-related parameters is selection of the proper equations by identifying the specific type of fault scarp and the corresponding calculation method.展开更多
【目的】研究Rothermel林火蔓延速率预测模型及另外2种以Rothermel模型为核心的蔓延速率预测模型对南方8种典型森林地表死可燃物的适用性,为林火蔓延速率预测提供理论支撑和指导。【方法】以南方地区8种典型速率地表死可燃物为对象,根...【目的】研究Rothermel林火蔓延速率预测模型及另外2种以Rothermel模型为核心的蔓延速率预测模型对南方8种典型森林地表死可燃物的适用性,为林火蔓延速率预测提供理论支撑和指导。【方法】以南方地区8种典型速率地表死可燃物为对象,根据研究对象的野外实际条件,在东北林业大学帽儿山实验林场风洞实验室内,构建不同可燃物床层含水率、载量及高度的可燃物床层,每种可燃物在平地无风条件下进行36次点烧试验,共288次点烧,记录每种可燃物类型不同配比条件下的蔓延速率。通过直接使用Rothermel模型、重新估计Rothermel模型参数、对Rothermel模型形式改进后自建模型的对比,得到最合适的预测模型。【结果】 1)平地无风条件下,南方8种典型森林地表死可燃物床层最大蔓延速率为0.55 m ·min -1 ,平均蔓延速率由大到小依次为:华山松、云南松、毛竹、柳杉、杉木、马尾松、麻栎及青冈栎。2)直接使用Rothermel模型预测的林火蔓延速率误差较大,平均绝对误差为0.18 m ·min -1 ,平均相对误差为70.0%。3)重新估计参数后的Rothermel模型及自建模型,预测的可燃物蔓延速率精度显著提高,平均绝对误差分别为0.04、0.037 m ·min -1 ,平均相对误差分别<18%、16.45%。4)重新估计参数的Rothermel模型与自建模型的预测误差的差异不显著,其中自建模型的预测值与实测值的 R 2 变化在0.71~0.90,平均为0.80。【结论】对南方8种典型森林的地表死可燃物类型,在平地无风条件下,重新估计参数的Rothermel模型及自建模型的预测精度相近,但自建模型可能更简单易用,可预测平地无风条件下可燃物地表火蔓延速率。展开更多
基金Under the auspices of Foundational Research Fund of Science Application in Sichuan Province (No. 05J029-098)
文摘The research on Constructed Soil Rapid Infiltration(CSRI) system is in its infancy at home and abroad.There are several details about the mechanism and application of CSRI system needed to be further studied.A major limitation in the current research is the absence of degradation dynamics of pollutants,and the height of filtration bed in CSRI system currently determined by empirical judgment lacks accuracy and logicality.To solve these two prob-lems,the soil column of CSRI system was utilized to treat domestic wastewater,meanwhile,the NH3-N degradation dynamics were studied according to the Monod equation,the research of Mann A T and the NH3-N degradation law.Then the mathematical model of filtration bed height was built based on NH3-N degradation dynamics equation in the soil column.It has been proven that within a limited range this model can calculate the appropriate height of filtration bed accurately in order to optimize technological parameters of hydraulic load and the concentration of influent NH3-N,improving the effluent quality of CSRI system.
基金funded by Basic Research Program of Jiangsu(grant Nos.BK20240106 and BK20240014)National Natural Science Foundation of China(grant Nos.52174265,52425407,and 52274278).
文摘Characterizing the hydrodynamics of a fluidized bed flotation column is essential for understanding the behavior of this multiphase flow system.Bed pressure fluctuations and phase hold-ups are two of these key characteristics.Static bed height effects on these two key characteristics were comprehensively studied using experimental and statistical analysis operating for different flow regimes.And three different bed height-to-diameter ratios(H/D=1.0,1.5,and 2.0)were investigated.The time series signals of pressure fluctuation were recorded via a pressure transducer,then analyzed through time and frequency domain methods.Cross-sectional and radial combined gas and solid hold-ups distribution were detected through the electrical resistance tomography under different H/D ratios.Results indicated that the key parameters of bed pressure fluctuation signals and gas-solid hold-up distributions are significantly affected by the change in static bed height,which can be explained by differences in bubble dynamics and particle movement behaviors.
基金supported by the "Major Pro-gram of National Natural Science Foundation of China" (Grant No.20490200)"National Natural Science Funds for Dis-tinguished Young Scholar"(Grant No.20525621)
文摘To study olefin reduction by using an auxiliary reactor for FCC naphtha upgrading, a large-scale cold model of a riser-bed coupled to an upper fluidized bed was established. The effect of static bed height in the upper fluidized bed on narticle flow behavior in the lower riser was investigated experimentally. A restriction index of solids holdup was used to evaluate quantitatively the restrictive effect of the upper fluidized bed. Experimental results show that, under the restrictive effect of the upper fluidized bed, the riser could be divided into three regions in the longitudinal direction： accelerating, fully developed and restriction. The axial distribution of solids holdup in the riser is characterized by large solids holdup in the top and bottom sections and small solids holdup in the middle section. Overall solids holdup increased with increasing static bed height in the upper fluidized bed, while particle velocity decreased. Such restrictive effect of the upper fluidized bed could extend from the middle and top sections to the whole riser volume when riser outlet resistance is increased, which increases with increasing static bed height in the upper fluidized bed. The upper bed exerts the strongest restriction on the area close to the riser outlet.
文摘The impact of temperature and particle size on minimumfluidizing velocity was studied and analyzed in a small pilot scale of bubbling fluidized bed reactor.This study was devoted to providing some data about fluidization to the literature under high temperature conditions.The experiments were carried out to evaluate the minimum fluidizing velocity over a vast range of temperature levels from 20℃ to 850℃ using silica sand with a particle size of 300-425μm,425-500μm,500-600μm,and 600-710μm.Furthermore,the variation in the minimumfluidized voidage was determined experimentally at the same conditions.The experimental data revealed that the Umf directly varied with particle size and inversely with temperature,whileεmf increases slightly with temperature based on the measurements of height at incipient fluidization.However,for all particle sizes used in this test,temperatures above 700℃ has a marginal effect on Umf.The results were compared with many empirical equations,and it was found that the experimental result is still in an acceptable range of empirical equations used.In which,our findings are not well predicted by the widely accepted correlations reported in the literature.Therefore,a new predicted equation has been developed that also accounts for the affecting of mean particle size in addition to other parameters.A good mean relative deviation of 5.473% between the experimental data and the predicted values was estimated from the correlation of the effective dimensionless group.Furthermore,the experimental work revealed that the minimum fluidizing velocity was not affected by the height of the bed even at high temperature.
文摘The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.
基金supported by the Science and Technology Program of Shanxi Province(2014KJXX-18)the Spark Programs of Earthquake Sciences(XH14069)
文摘Fault-related parameters are critical for studying tectonic evolution, deformation character- istics, active tectonism, and seismic hazards. A new method of calculating reverse-fault- related parameters has been developed, which uses systematic analysis of the geometrical characteristics of normal and reverse scarps of reverse faults together with measurements of topographic profiles and fault bedding. The results show that the most suitable method of calculating fault parameters heavily relies on the specific type of fault scarp. For a reverse scarp, the size of the vertical displacement （VD） of the fault, the vertical separation （VS） of the hanging wall and the footwall, and the fault scarp height （SH）how the relationship VD ≥VS ≥ SH; conversely, for normal scarps, VD ≤ VS ≤ SH. The theoretical equations were used to study fault deformation in the Southwest Tianshan Mountain foreland basin. The results showed that, for every fault, VD ≥ VS ≥SH, which is consistent with our predicted relationship. This finding demonstrates that this method is suitable to explore structural information of reverse faults. In the study area, the vertical displacement is 1.4 times the horizontal displacement, suggesting that fiexural-slip faults may play an important role in transferring local deformation from horizontal shortening to vertical uplift. Therefore, one of the most important steps in correct calculation of reverse-fault-related parameters is selection of the proper equations by identifying the specific type of fault scarp and the corresponding calculation method.
文摘【目的】研究Rothermel林火蔓延速率预测模型及另外2种以Rothermel模型为核心的蔓延速率预测模型对南方8种典型森林地表死可燃物的适用性,为林火蔓延速率预测提供理论支撑和指导。【方法】以南方地区8种典型速率地表死可燃物为对象,根据研究对象的野外实际条件,在东北林业大学帽儿山实验林场风洞实验室内,构建不同可燃物床层含水率、载量及高度的可燃物床层,每种可燃物在平地无风条件下进行36次点烧试验,共288次点烧,记录每种可燃物类型不同配比条件下的蔓延速率。通过直接使用Rothermel模型、重新估计Rothermel模型参数、对Rothermel模型形式改进后自建模型的对比,得到最合适的预测模型。【结果】 1)平地无风条件下,南方8种典型森林地表死可燃物床层最大蔓延速率为0.55 m ·min -1 ,平均蔓延速率由大到小依次为:华山松、云南松、毛竹、柳杉、杉木、马尾松、麻栎及青冈栎。2)直接使用Rothermel模型预测的林火蔓延速率误差较大,平均绝对误差为0.18 m ·min -1 ,平均相对误差为70.0%。3)重新估计参数后的Rothermel模型及自建模型,预测的可燃物蔓延速率精度显著提高,平均绝对误差分别为0.04、0.037 m ·min -1 ,平均相对误差分别<18%、16.45%。4)重新估计参数的Rothermel模型与自建模型的预测误差的差异不显著,其中自建模型的预测值与实测值的 R 2 变化在0.71~0.90,平均为0.80。【结论】对南方8种典型森林的地表死可燃物类型,在平地无风条件下,重新估计参数的Rothermel模型及自建模型的预测精度相近,但自建模型可能更简单易用,可预测平地无风条件下可燃物地表火蔓延速率。
