The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the bottom.Although the chute aerators were widely investigated experimentally,the air concentr...The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the bottom.Although the chute aerators were widely investigated experimentally,the air concentration distribution of the lower jet in the impact zone remains to be explored systematically.In the impact zone,it is observed that a portion of the air stays in the rollers instead of traveling with the flow,decreasing the air transportation capacity.Based on extensive tests,a comprehensive formula is developed to compute the air concentration distribution in the impact zone,with results in good agreement with the model tests.展开更多
The supersonic oxygen supply technology, including the coherent supersonic jet and the conventional supersonic jet, is now widely adopted in electric arc furnace steelmaking process to increase the bath stirring, reac...The supersonic oxygen supply technology, including the coherent supersonic jet and the conventional supersonic jet, is now widely adopted in electric arc furnace steelmaking process to increase the bath stirring, reaction rates and energy efficiency. However, there has been limited study on the impact characteristics of the coherent supersonic jet and the conventional supersonic jet. Thus, integrating theoretical models and numerical simulations, an optimized theoretical model was developed to calculate the volume of the impact zone generated by coherent and conventional supersonic jets. The optimized theoretical model was validated by water model experiments. The results show that the jet impact zone volume with coherent supersonic jet is much larger than that with conventional supersonic jet at the same lance height. The kd value, a newly defined variable that is the product of the dimensionless quantity of velocity and free distance, reflects the velocity attenuation and the potential core length of the main supersonic jet, which is a key parameter of the optimized theoretical model. The optimized theoretical model can well predict the jet impact zone volumes of coherent and conventional supersonic jets with the error no more than 3.62 and 9.37%, respectively.展开更多
Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac- tive relatio...Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac- tive relationship with a variety of meteorological elements, it is found that the high-value zone of aerosol optical depth derived from the Total Ozone Mapping Spectrometer (TOMS), its significant negative correlation zones in terms of sunshine duration (SD) and surface air temperature (SAT) and its significant positive correlation zones with low-level cloud amount (LCC) are co-located in the South China region during warm periods. Based on this finding, the region is referred to as a "significant impact zone" (SI zone) affected by aerosols. Then, a comparative analysis is made on variation differ- ences of observed SAT, SD and LCC, etc. in different regions. It is also found that the LCC is increased and the SD is decreased within the "SI zone" over eastern China during the warm season. These characteristics are more evident than those beyond the zone, while the warming trend within the zone is evidently weaker than that outside it. Studies show that since recent 20 a, under the influence of aerosols, the LCC tend to increase substantially with a clear decrease of SD and an unnoticeable warming trend within the "SI zone". Comparing with the climate change beyond the zone, the difference is significant. Therefore, the effects of atmospheric aerosols on climate is possibly one of the contri- butions to the difference of climate change existed between the southern and northern parts of the Eastern China during a warm season.展开更多
This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test w...This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test were applied to compare the speed and flow characteristics between work zone and non-work zone conditions. Furthermore, we analyzed the mobility characteristics of freeway work zones within the urban area of Milwaukee, WI, USA. More than 50% of investigated work zones have experienced speed reduction and 15%-30% is necessary reduced volumes. Speed reduction was more significant within and at the downstream of work zones than at the upstream.展开更多
This paper discusses briefly the elementary characteristics of the east China economic developing zone, and analyses the condition of urban atmospheric pollution, water pollution and ecological damage in this zone at ...This paper discusses briefly the elementary characteristics of the east China economic developing zone, and analyses the condition of urban atmospheric pollution, water pollution and ecological damage in this zone at present. It was brought forward that we must pay great attention to the environmental factors, and make the environmental impact assessment and environmental planning in the process of economic development in this zone.展开更多
基金supported by the National Key Research and Development Program opf China(Grant No.2016YFC0401707).
文摘The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the bottom.Although the chute aerators were widely investigated experimentally,the air concentration distribution of the lower jet in the impact zone remains to be explored systematically.In the impact zone,it is observed that a portion of the air stays in the rollers instead of traveling with the flow,decreasing the air transportation capacity.Based on extensive tests,a comprehensive formula is developed to compute the air concentration distribution in the impact zone,with results in good agreement with the model tests.
文摘The supersonic oxygen supply technology, including the coherent supersonic jet and the conventional supersonic jet, is now widely adopted in electric arc furnace steelmaking process to increase the bath stirring, reaction rates and energy efficiency. However, there has been limited study on the impact characteristics of the coherent supersonic jet and the conventional supersonic jet. Thus, integrating theoretical models and numerical simulations, an optimized theoretical model was developed to calculate the volume of the impact zone generated by coherent and conventional supersonic jets. The optimized theoretical model was validated by water model experiments. The results show that the jet impact zone volume with coherent supersonic jet is much larger than that with conventional supersonic jet at the same lance height. The kd value, a newly defined variable that is the product of the dimensionless quantity of velocity and free distance, reflects the velocity attenuation and the potential core length of the main supersonic jet, which is a key parameter of the optimized theoretical model. The optimized theoretical model can well predict the jet impact zone volumes of coherent and conventional supersonic jets with the error no more than 3.62 and 9.37%, respectively.
基金the International Sci-Tech Cooperative Project under the auspices of the Ministry of Science and Technology of the People’s Republic of China (No.2004DFA06100)
文摘Through analysis of the distribution pattern and changing characteristics of atmospheric aerosols over the East Asia region during warm seasons in recent 20 a and beyond as well as their possible interac- tive relationship with a variety of meteorological elements, it is found that the high-value zone of aerosol optical depth derived from the Total Ozone Mapping Spectrometer (TOMS), its significant negative correlation zones in terms of sunshine duration (SD) and surface air temperature (SAT) and its significant positive correlation zones with low-level cloud amount (LCC) are co-located in the South China region during warm periods. Based on this finding, the region is referred to as a "significant impact zone" (SI zone) affected by aerosols. Then, a comparative analysis is made on variation differ- ences of observed SAT, SD and LCC, etc. in different regions. It is also found that the LCC is increased and the SD is decreased within the "SI zone" over eastern China during the warm season. These characteristics are more evident than those beyond the zone, while the warming trend within the zone is evidently weaker than that outside it. Studies show that since recent 20 a, under the influence of aerosols, the LCC tend to increase substantially with a clear decrease of SD and an unnoticeable warming trend within the "SI zone". Comparing with the climate change beyond the zone, the difference is significant. Therefore, the effects of atmospheric aerosols on climate is possibly one of the contri- butions to the difference of climate change existed between the southern and northern parts of the Eastern China during a warm season.
基金Project(61620106002)supported by the National Natural Science Foundation of ChinaProject(2016YFB0100906)supported by the National Key R&D Program in China+1 种基金Project(2015364X16030)supported by the Information Technology Research Project of Ministry of Transport of ChinaProject(2242015K42132)supported by the Fundamental Sciences of Southeast University,China
文摘This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test were applied to compare the speed and flow characteristics between work zone and non-work zone conditions. Furthermore, we analyzed the mobility characteristics of freeway work zones within the urban area of Milwaukee, WI, USA. More than 50% of investigated work zones have experienced speed reduction and 15%-30% is necessary reduced volumes. Speed reduction was more significant within and at the downstream of work zones than at the upstream.
文摘This paper discusses briefly the elementary characteristics of the east China economic developing zone, and analyses the condition of urban atmospheric pollution, water pollution and ecological damage in this zone at present. It was brought forward that we must pay great attention to the environmental factors, and make the environmental impact assessment and environmental planning in the process of economic development in this zone.
