In many gasliquid processes, the initial bubble size is determined by a series of operation parameters along with the sparger design and gasliquid flow pattern. Bubble formation models for variant gasliquid flow pat t...In many gasliquid processes, the initial bubble size is determined by a series of operation parameters along with the sparger design and gasliquid flow pattern. Bubble formation models for variant gasliquid flow pat terns have been developed based on force balance. The effects of the orientation of gasliquid flow, gas velocity, liquid velocity and orifice diameter on the initial bubble size have been clarified. In ambient airwater system, thesultable gasllquid flow pattern is important to obtain smaller bubbles under the low velocity liquid crossflow con ditions with stainless steel spargers. Among the four types of gasliquid flow patterns discussed, the horizontal orifice in a vertically upward liquid flow produces the smallest initial bubbles. However the orientation effects of gas and liquid flow are found tobe insgnifican whenliq.uid velocity is.higher than. 3.2 m;sa or theorifice diameter is small enough.展开更多
Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Proph...Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Prophet Mosque in Al-Madinah A l-Munawarah from early 12：00 to 14：00 of Friday and from 19：00 to 22：30 at holy month, Ramadan. The percentage of both carbon monoxide （CO） and nitrogen dioxide （NO2） had significantly increased （p 〈 0.05-0.005）. The peak levels of these air pollutants were between 13：15-13：20 during Fridays. The increase in the emission of these exhausted gases was concomitant with the significant decrease （p 〈 0.05） in oxygen （02） levels but the latter recovered its levels after 13：20 hours. The arithmetic total mean density of vehicle per minute （vpm） at Salam Road, the busiest road of Al-Madinah, during hours （07：00-09：00）, （13：00-15：00） and （17：00-19：00） of both Friday and Saturdays respectively were （8/45, 16/40 and 36/43）. The increase in air pollution has been attributed to a dramatic increase in number of public cars use the car parks during these times, the consequent congestion at entries, the excess or/and poor consumption of fuels being utilized and the inadequate ventilation.展开更多
基金Supported by the National Natural Science Foundation of China （20736009）.
文摘In many gasliquid processes, the initial bubble size is determined by a series of operation parameters along with the sparger design and gasliquid flow pattern. Bubble formation models for variant gasliquid flow pat terns have been developed based on force balance. The effects of the orientation of gasliquid flow, gas velocity, liquid velocity and orifice diameter on the initial bubble size have been clarified. In ambient airwater system, thesultable gasllquid flow pattern is important to obtain smaller bubbles under the low velocity liquid crossflow con ditions with stainless steel spargers. Among the four types of gasliquid flow patterns discussed, the horizontal orifice in a vertically upward liquid flow produces the smallest initial bubbles. However the orientation effects of gas and liquid flow are found tobe insgnifican whenliq.uid velocity is.higher than. 3.2 m;sa or theorifice diameter is small enough.
文摘Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Prophet Mosque in Al-Madinah A l-Munawarah from early 12：00 to 14：00 of Friday and from 19：00 to 22：30 at holy month, Ramadan. The percentage of both carbon monoxide （CO） and nitrogen dioxide （NO2） had significantly increased （p 〈 0.05-0.005）. The peak levels of these air pollutants were between 13：15-13：20 during Fridays. The increase in the emission of these exhausted gases was concomitant with the significant decrease （p 〈 0.05） in oxygen （02） levels but the latter recovered its levels after 13：20 hours. The arithmetic total mean density of vehicle per minute （vpm） at Salam Road, the busiest road of Al-Madinah, during hours （07：00-09：00）, （13：00-15：00） and （17：00-19：00） of both Friday and Saturdays respectively were （8/45, 16/40 and 36/43）. The increase in air pollution has been attributed to a dramatic increase in number of public cars use the car parks during these times, the consequent congestion at entries, the excess or/and poor consumption of fuels being utilized and the inadequate ventilation.
