Voids are important regions in some industrial processes,particularly in the iron-making process,because a void is a zone in which gas-solid heat transfer and reactions occur.This paper presents a 3D experimental stud...Voids are important regions in some industrial processes,particularly in the iron-making process,because a void is a zone in which gas-solid heat transfer and reactions occur.This paper presents a 3D experimental study of void formation measurement with 2D projection in a packed bed using an optical method.By developing an experimental laser-attenuation scanning method,invisible voids that form in a packed bed can be detected and identified as relatively stable ellipsoids.The effects of various operational parameters on void formation are analyzed in terms of the resulting void sizes and shapes.The results show that the void shape that forms in the packed bed is close to an ellipsoid and is relatively stable.The void size is positively correlated with the blast volume rate and is negatively correlated with the blowpipe diameter.The blowpipe depth has no significant effect on either the void formation or size.The blast angle affects the void location strongly;when this angle is increased,the void moves upward.The information and methods obtained in this experiment are significant in aiding understanding of the mechanism of void formation in gas-solid reactors.展开更多
In order to improve the efficiency of reducing fine dust emissions from diffuse sources,the commonly used water mist can be electrostatically charged.Thus,the attraction between particles and droplets increases due to...In order to improve the efficiency of reducing fine dust emissions from diffuse sources,the commonly used water mist can be electrostatically charged.Thus,the attraction between particles and droplets increases due to electrostatic field forces.In the experimental investigations carried out,an electrostatic two-fluid nozzle was used to generate a charged spray mist according to the principle of charging by induction.In a chamber,dispersed dust was precipitated with the spray mist,while detecting the laser light attenuation.By means of comparative measurements it could be shown that faster sedimentation and separation takes place through electrostatic attraction.Parameter variations regarding the use of compressed air and water were investigated and the sedimentation time of the particle-droplet mixture in the chamber was shown.A size distribution was then calculated from the laser light attenuation,which shows that the proportion of small particles decreases with spray application.Furthermore,the influence of the polarity of droplets and solid particles on the reduction measure was determined.展开更多
基金This work was supported by the National Key Research and Development Program of China(grant number 2018YFB0605903).
文摘Voids are important regions in some industrial processes,particularly in the iron-making process,because a void is a zone in which gas-solid heat transfer and reactions occur.This paper presents a 3D experimental study of void formation measurement with 2D projection in a packed bed using an optical method.By developing an experimental laser-attenuation scanning method,invisible voids that form in a packed bed can be detected and identified as relatively stable ellipsoids.The effects of various operational parameters on void formation are analyzed in terms of the resulting void sizes and shapes.The results show that the void shape that forms in the packed bed is close to an ellipsoid and is relatively stable.The void size is positively correlated with the blast volume rate and is negatively correlated with the blowpipe diameter.The blowpipe depth has no significant effect on either the void formation or size.The blast angle affects the void location strongly;when this angle is increased,the void moves upward.The information and methods obtained in this experiment are significant in aiding understanding of the mechanism of void formation in gas-solid reactors.
文摘In order to improve the efficiency of reducing fine dust emissions from diffuse sources,the commonly used water mist can be electrostatically charged.Thus,the attraction between particles and droplets increases due to electrostatic field forces.In the experimental investigations carried out,an electrostatic two-fluid nozzle was used to generate a charged spray mist according to the principle of charging by induction.In a chamber,dispersed dust was precipitated with the spray mist,while detecting the laser light attenuation.By means of comparative measurements it could be shown that faster sedimentation and separation takes place through electrostatic attraction.Parameter variations regarding the use of compressed air and water were investigated and the sedimentation time of the particle-droplet mixture in the chamber was shown.A size distribution was then calculated from the laser light attenuation,which shows that the proportion of small particles decreases with spray application.Furthermore,the influence of the polarity of droplets and solid particles on the reduction measure was determined.
