This paper tries to determine the economical type of reinforced concrete chimney structure based on the same effective height of chimney. The simulated experiments of wind tunnel are performed for the study, which com...This paper tries to determine the economical type of reinforced concrete chimney structure based on the same effective height of chimney. The simulated experiments of wind tunnel are performed for the study, which compare multi-tube chimney with single tube chimney based on the same buoyancy flux of plume. According to the comparison among the experiment results and the previous study of plume rise, the paper defines some final plume rise models. Finally, the paper gives the cost-benefit analysis after making cost estimation for different types of chimney structure and recommends the economical and reasonable type of chimney structure in light of the same environmental benefits.展开更多
Considering the effects of both entrainment and intensification of the exchanges of momentum and heat between plume and ambient air,we have derived the trajectory equation of buoyant plume under neutral conditions,and...Considering the effects of both entrainment and intensification of the exchanges of momentum and heat between plume and ambient air,we have derived the trajectory equation of buoyant plume under neutral conditions,and the final rise prediction formula theoretically without any hypotheses on the rise termination.Compared with the field experi- ments,the final rise formula simulates the observed final rise heights well.展开更多
As fate and transport of air emissions from animal housing systems is of increasing concern, dispersion models have become commonly used tools to estimate the downwind concentrations of pollutants at certain locations...As fate and transport of air emissions from animal housing systems is of increasing concern, dispersion models have become commonly used tools to estimate the downwind concentrations of pollutants at certain locations surrounding the animal production farms. In application of Gaussian dispersion model for downwind concentration predictions of animal housing emissions, unknown plume rise (△h) and plume shape of the horizontally emitted plumes from animal housing systems have been vital weak points challenging the accuracy of the model predictions. This paper reports an inverse AERMOD modeling study to derive the plum rises of PM10 emissions from mechanically ventilated egg production houses based upon field measurements of PM10 emission rate, downwind concentrations, and meteorological conditions. In total, 87 hourly plume rises were found for 20 days (five days per season for four seasons, from fall 2008 to summer 2009). The mean plume rises for fall 2008, winter 2008, spring 2009 and summer 2009 were 16.2 m (SE = 11.2 m), 7.9 m (SE = 9.5 m), 16.5 m (SE = 12.4 m), and 14.3 m (SE = 10.0 m), respectively. The relationships between plume rises and various factors were tested. While the diurnal patterns of the plume rises were not consistent among different selective days, they generally followed the diurnal patterns of house ventilation rates. Plume rise for weekends were significantly higher than those for weekdays in fall. Multiple linear regression showed a significant positive relationship (p = 0.0134) between wind speed and the plume rises. Ambient relative humidity and total volume flow were also found to be slightly (p = 0.171 and 0.217, respectively) related to the plume rises.展开更多
Oceanic plateaus are a significant type of large igneous provinces in the oceans,providing insights to regional tectonic events and mantle behavior.The three world's largest oceanic plateaus,the Ontong Java Platea...Oceanic plateaus are a significant type of large igneous provinces in the oceans,providing insights to regional tectonic events and mantle behavior.The three world's largest oceanic plateaus,the Ontong Java Plateau,the Kerguelen Plateau and the Shatsky Rise,are representatives in displaying extraordinary fluxes of magma from mantle to lithosphere.Detailed description incorporating transdisciplinary observations on marine geology,geophysics and geochemistry allow us to test the two lively-debated oceanic plateau formation hypotheses(mantle plume and plate boundary models).Predictions from either hypothesis merely obtain partial support.It is therefore unclear to differentiate one model from another one regarding the oceanic plateau formation.Careful comparisons of the three oceanic plateaus show many commonalities and even more differences in their formation and evolution.This diversity signifies one may not be typical of all.Notably,several key common features,i.e.,massive and rapid eruption and near-ridge formation setting,imply that the lithospheric volcanic emplacement of oceanic plateaus was controlled by seafloor spreading despite a mantle plume exists peripherally.If a coincidence of mantle plume and spreading ridge occurs,it may indicate a plume-ridge interaction.One possible mechanism is that spreading ridge is dragged by a plume and migrates to the location of the plume.Another possibility is that the asthenosphere is fed by a plume nearby and generates melting anomalies along the spreading ridge.展开更多
Various dispersion models have been developed to simulate the fate and transport of air emissions from animal housing systems to meet the increasing need for knowledge in this area. However, the accuracy of the models...Various dispersion models have been developed to simulate the fate and transport of air emissions from animal housing systems to meet the increasing need for knowledge in this area. However, the accuracy of the models may be challenged due to the unknown plume rise and plume shape. This paper reports a combination of theoretical and field study of the plum rise and shape of air flow from a ventilation fan commonly used in mechanically ventilated animal houses. The theoretical modeling of the plume shape was conducted using a commercial Computational Fluid Dynamics (CFD) package named FloEFD;the field measurements of the plume field was conducted using five 3D ultrasonic anemometers to simultaneously measure the air flow in the plume at various locations (four heights and five downwind distances). The TECPLOT package was used to visualize the plume flow field based upon anemometer measurements. While the plume shapes were found to be left-shifted by the CFD model and TECPLOT visualization, the magnitudes of the 3D wind velocities from field measurement were found to be significantly larger than those from CFD model. The plume field measurements indicated that the plume of a 0.6 m (24-inch) ventilation fan had a depth about 9 m, a width about ±6 m, and a rise (lifting) beyond the highest measurement point, 4.88 m (16 ft).展开更多
文摘This paper tries to determine the economical type of reinforced concrete chimney structure based on the same effective height of chimney. The simulated experiments of wind tunnel are performed for the study, which compare multi-tube chimney with single tube chimney based on the same buoyancy flux of plume. According to the comparison among the experiment results and the previous study of plume rise, the paper defines some final plume rise models. Finally, the paper gives the cost-benefit analysis after making cost estimation for different types of chimney structure and recommends the economical and reasonable type of chimney structure in light of the same environmental benefits.
文摘Considering the effects of both entrainment and intensification of the exchanges of momentum and heat between plume and ambient air,we have derived the trajectory equation of buoyant plume under neutral conditions,and the final rise prediction formula theoretically without any hypotheses on the rise termination.Compared with the field experi- ments,the final rise formula simulates the observed final rise heights well.
文摘As fate and transport of air emissions from animal housing systems is of increasing concern, dispersion models have become commonly used tools to estimate the downwind concentrations of pollutants at certain locations surrounding the animal production farms. In application of Gaussian dispersion model for downwind concentration predictions of animal housing emissions, unknown plume rise (△h) and plume shape of the horizontally emitted plumes from animal housing systems have been vital weak points challenging the accuracy of the model predictions. This paper reports an inverse AERMOD modeling study to derive the plum rises of PM10 emissions from mechanically ventilated egg production houses based upon field measurements of PM10 emission rate, downwind concentrations, and meteorological conditions. In total, 87 hourly plume rises were found for 20 days (five days per season for four seasons, from fall 2008 to summer 2009). The mean plume rises for fall 2008, winter 2008, spring 2009 and summer 2009 were 16.2 m (SE = 11.2 m), 7.9 m (SE = 9.5 m), 16.5 m (SE = 12.4 m), and 14.3 m (SE = 10.0 m), respectively. The relationships between plume rises and various factors were tested. While the diurnal patterns of the plume rises were not consistent among different selective days, they generally followed the diurnal patterns of house ventilation rates. Plume rise for weekends were significantly higher than those for weekdays in fall. Multiple linear regression showed a significant positive relationship (p = 0.0134) between wind speed and the plume rises. Ambient relative humidity and total volume flow were also found to be slightly (p = 0.171 and 0.217, respectively) related to the plume rises.
基金supported by the National Key R&D Program of China(No.2018YFC0309800)the National Natural Science Foundation of China(Nos.91628301,U1606401,41606069,41776058,41890813)+3 种基金the Natural Science Foundation of Guangdong Province in China(No.2017A030313243)the Chinese Academy of Sciences(Nos.Y4SL021001,QYZDY-SSW-DQC005,133244KY SB20180029)the China Association of Marine Affairs(No.CAMAZD201714)the Asia-Pacific Economic Cooperation(No.12119016)
文摘Oceanic plateaus are a significant type of large igneous provinces in the oceans,providing insights to regional tectonic events and mantle behavior.The three world's largest oceanic plateaus,the Ontong Java Plateau,the Kerguelen Plateau and the Shatsky Rise,are representatives in displaying extraordinary fluxes of magma from mantle to lithosphere.Detailed description incorporating transdisciplinary observations on marine geology,geophysics and geochemistry allow us to test the two lively-debated oceanic plateau formation hypotheses(mantle plume and plate boundary models).Predictions from either hypothesis merely obtain partial support.It is therefore unclear to differentiate one model from another one regarding the oceanic plateau formation.Careful comparisons of the three oceanic plateaus show many commonalities and even more differences in their formation and evolution.This diversity signifies one may not be typical of all.Notably,several key common features,i.e.,massive and rapid eruption and near-ridge formation setting,imply that the lithospheric volcanic emplacement of oceanic plateaus was controlled by seafloor spreading despite a mantle plume exists peripherally.If a coincidence of mantle plume and spreading ridge occurs,it may indicate a plume-ridge interaction.One possible mechanism is that spreading ridge is dragged by a plume and migrates to the location of the plume.Another possibility is that the asthenosphere is fed by a plume nearby and generates melting anomalies along the spreading ridge.
文摘Various dispersion models have been developed to simulate the fate and transport of air emissions from animal housing systems to meet the increasing need for knowledge in this area. However, the accuracy of the models may be challenged due to the unknown plume rise and plume shape. This paper reports a combination of theoretical and field study of the plum rise and shape of air flow from a ventilation fan commonly used in mechanically ventilated animal houses. The theoretical modeling of the plume shape was conducted using a commercial Computational Fluid Dynamics (CFD) package named FloEFD;the field measurements of the plume field was conducted using five 3D ultrasonic anemometers to simultaneously measure the air flow in the plume at various locations (four heights and five downwind distances). The TECPLOT package was used to visualize the plume flow field based upon anemometer measurements. While the plume shapes were found to be left-shifted by the CFD model and TECPLOT visualization, the magnitudes of the 3D wind velocities from field measurement were found to be significantly larger than those from CFD model. The plume field measurements indicated that the plume of a 0.6 m (24-inch) ventilation fan had a depth about 9 m, a width about ±6 m, and a rise (lifting) beyond the highest measurement point, 4.88 m (16 ft).
