飞机客舱环境控制系统是飞机设计必须要考虑的因素,基于Fluent软件进行二次开发,建立客舱环控系统内流场的数值模拟流程,选取MA600飞机进行客舱全尺寸三维建模,对该客舱的温度场、速度场及CO2浓度分布进行数值仿真,再用平均温度评价指...飞机客舱环境控制系统是飞机设计必须要考虑的因素,基于Fluent软件进行二次开发,建立客舱环控系统内流场的数值模拟流程,选取MA600飞机进行客舱全尺寸三维建模,对该客舱的温度场、速度场及CO2浓度分布进行数值仿真,再用平均温度评价指标和热环境综合评价指标PMV(Predicted Mean Vote)对客舱进行温度环境客观评价。数值仿真结果表明:MA600客舱乘客周围空气的温度、速度和CO2浓度基本达到了客舱舒适度要求,但乘客自身的热舒适指标略微偏高,躯干和脚部由于偏暖而略感不舒适。该方法是客舱环控系统评估的一种有效数值模拟手段,在工程方面具有一定的实用价值。展开更多
Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and it...Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and its adverse health effects, studies on anthropogenic contributions to the increasing levels of GHG, particularly from livestock waste management practices, have not been adequately explored, especially in less developed countries. This study determined waste management practices and outdoor levels of CH4 and CO2 at three selected livestock farms （A-C） in Ibadan, Oyo State, Nigeria. Each study farm consisted of poultry, cattle and pig units. A 30-point observational checklist documented adequacy of solid waste management practices. Ambient concentrations of CH4 and CO2 at farm buildings and at waste disposal sites were monitored every other day, twice each day of monitoring （morning and evening hours）, for eight weeks during months of September-November in 2013. Average scores for the waste management practices for Farms A-C were 29.6%, 33.3% and 18.5%, respectively. Morning and evening CH4 concentrations in parts per million （ppm） at main buildings of Farms A-C were 2,538 ± 773 and 1,916 ± 662, 2,325 ± 773 and 1,180 ± 483, and 2,389 ± 687 and 1,854 ± 571, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C main buildings were 350 ± 130 and 330 ± 110, 470 ± 100 and 440 ± 100, and 430 ± 80 and 400 ± 70, respectively. Morning and evening CH4 concentrations （ppm） at Farms A-C waste disposal sites were 2,452 ± 495 and 1,614 ± 372, 1,527 ± 390 and 1,736 ± 269, and 2,345 ± 615 and 1,690 ± 387, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C waste disposal sites were 330 ± 90, 370 ± 60 and 350 ± 30, respectively. Waste management practices were inadequate; solid waste management practices like infrequent evacuation of slurry waste and open burning of waste may have contributed to the production of CH4 and CO2. This study suggested proper handling, removal and disposal of farm waste which can reduce production of GHGs like CH4 and CO2.展开更多
文摘飞机客舱环境控制系统是飞机设计必须要考虑的因素,基于Fluent软件进行二次开发,建立客舱环控系统内流场的数值模拟流程,选取MA600飞机进行客舱全尺寸三维建模,对该客舱的温度场、速度场及CO2浓度分布进行数值仿真,再用平均温度评价指标和热环境综合评价指标PMV(Predicted Mean Vote)对客舱进行温度环境客观评价。数值仿真结果表明:MA600客舱乘客周围空气的温度、速度和CO2浓度基本达到了客舱舒适度要求,但乘客自身的热舒适指标略微偏高,躯干和脚部由于偏暖而略感不舒适。该方法是客舱环控系统评估的一种有效数值模拟手段,在工程方面具有一定的实用价值。
文摘Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and its adverse health effects, studies on anthropogenic contributions to the increasing levels of GHG, particularly from livestock waste management practices, have not been adequately explored, especially in less developed countries. This study determined waste management practices and outdoor levels of CH4 and CO2 at three selected livestock farms （A-C） in Ibadan, Oyo State, Nigeria. Each study farm consisted of poultry, cattle and pig units. A 30-point observational checklist documented adequacy of solid waste management practices. Ambient concentrations of CH4 and CO2 at farm buildings and at waste disposal sites were monitored every other day, twice each day of monitoring （morning and evening hours）, for eight weeks during months of September-November in 2013. Average scores for the waste management practices for Farms A-C were 29.6%, 33.3% and 18.5%, respectively. Morning and evening CH4 concentrations in parts per million （ppm） at main buildings of Farms A-C were 2,538 ± 773 and 1,916 ± 662, 2,325 ± 773 and 1,180 ± 483, and 2,389 ± 687 and 1,854 ± 571, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C main buildings were 350 ± 130 and 330 ± 110, 470 ± 100 and 440 ± 100, and 430 ± 80 and 400 ± 70, respectively. Morning and evening CH4 concentrations （ppm） at Farms A-C waste disposal sites were 2,452 ± 495 and 1,614 ± 372, 1,527 ± 390 and 1,736 ± 269, and 2,345 ± 615 and 1,690 ± 387, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C waste disposal sites were 330 ± 90, 370 ± 60 and 350 ± 30, respectively. Waste management practices were inadequate; solid waste management practices like infrequent evacuation of slurry waste and open burning of waste may have contributed to the production of CH4 and CO2. This study suggested proper handling, removal and disposal of farm waste which can reduce production of GHGs like CH4 and CO2.
