| The filter cartridge dust collector has been widely used in engineering because of its small size,large filtration area,simple structure,convenient maintenance and replacement,etc.,but due to its complicated structure and many folds,the filter cartridge is not thoroughly cleaned and the overall cleaning is performed.The problem of unevenness has been plaguing engineers and technicians and has become a major obstacle to the development of its technology.Therefore,it is necessary to explore a new type of gas jet —the annular gas jet used for pulse jet cleaning and cleaning of the filter cartridge dust collector to improve the cleaning performance and overall uniformity.It is of great significance for the development and wide application of the filter cartridge dust collector technology.The research content of this paper is divided into the basic research on the flow characteristics of annular gas jet in semi-constrained space and the application research of annular gap pulse jet cleaning.In order to apply the annular gas jet to the pulse dust cleaning of the filter cartridge dust collector,the flow characteristics of the annular gas jet in the semi-constrained space should be studied first,and the flow characteristics of the annular gas jet in the semi-constrained space are firstly recognized.The numerical simulation method is used to study the flow characteristics of annular gas jet in semi-constrained space.It is concluded that:(1)annular gas jet has a strong ability to induce entrapment;(2)when the length of semi-confined space enables the annular gas jet to converge,The velocity of the central axis of the flow field first decreases,then increases to the peak and then decreases,and there is a convergence point.The position of the convergence point does not change with the change of the exit velocity of the annular seam;(3)the ejector coefficient increases with the exit speed of the annular seam increase rapidly firstly,and then decrease;(4)when the length of the semi-confined space is constant,the size of the negative pressure zone at the inlet does not change with the change of the exit velocity of the annular seam;as the velocity of the annular seam exit increases,the static pressure in the semi-constrained space along the length changes faster and faster;(5)the length of the semi-constrained space affects the flow pattern of the annular gas jet in the semi-constrained space,which directly affects the rate of change of static pressure inside the flow field and the ratio of the length of the negative pressure zone at the inlet to the total length of the semi-constrained space.The annular gas jet has high induced entrainment characteristics and stable uniformity,and the airflow is uniformly distributed in a circular shape,which can be used in the cleaning of the filter cartridge duster,and compared with the circular blowing airflow,its cleaning performance and uniformity are more dominant.Further study on the parameters of the annular injection structure(draft tube length,outflow angle,annular gap width,annular nozzle inner diameter,spray height,filter cartridge length)and operating parameters(injection pressure,injection time)on filter cartridge cleaning performance and uniformity influence,the research results show that:(1)annular nozzle with a certain length of the draft tube can improve the performance and uniformity of the filter dust collector;(2)The five structural parameters of the length of the draft tube,the outflow angle,the inner diameter of the annular nozzle,the blowing distance,and the width of the ring gap are too large or too small to reduce the cleaning performance and uniformity;(3)The long filter cartridge with a peak pressure of more than 1 m along the side wall of the measuring rod in the longitudinal direction of the filter cartridge increases first and then decreases,and annular pulse jet cleaning also has good cleaning performance and uniformity for long filter cartridges;(4)For the influence of operating parameters,increasing the blowing pressure and pulse width to a certain extent will improve the cleaning performance,excessive injection pressure will cause the filter cartridge to be damaged,and the excessive pulse width will increase the air consumption.In order to achieve the best cleaning effect,the structural parameters of the annular nozzle should be adjusted to make the annular blowing air flow into the filter cartridge in a diffused form,which enhances the diverging effect of the blowing airflow.Finally,the orthogonal test method is used to determine the influence of each structural parameter on the cleaning of the upper part of the filter dust collector and the optimal horizontal combination.The results of the study are as follows: The structural parameters are ordered according to the influence of the peak pressure of the side wall at a distance of 100 mm from the filter cylinder: the width of the ring gap > the length of the draft tube > the distance of the spray gun > the length of the filter drum > the inner diameter of the annular nozzle > the angle of the outflow.In the numerical simulation range of this study,when the average diameter of the filter cartridge is 80 mm,the length of the guide tube is x=80mm,the outflow angle is α=10°,the width of the annular slit is e=0.5mm,and the inner diameter of the annular nozzle is d=56mm,the distance H=200mm and the length of the filter cylinder L=1500mm are the optimal horizontal combination,and the peak value of the sidewall pressure at the 100 mm from the filter cylinder mouth is the largest. |
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