Research On Incipient Motion Of Dust For Bulk-cargo Storage Yard Of Harbors

Rapid development of the domestic economy has been driving the demands forore, coal and other raw materials. Ports, as the transportation hub of cargo, bear thetransport, transit and temporary storage task of the ore, coal and others. In thetransport and storage process of ore and coal, dust dispersion will not only result inloss of cargo, dust pollution on the port and its surrounding areas will also become aserious problem.Research will be carried out on the incipient motion of dust through fieldmeasurements at the ore yard of Caofeidian Port and the wind tunnel modelexperiment data will also be collected for analysis. Main conclusions are asfollowings.(1) The influencing factors on dust dispersion are complex and variable, includingthe meteorological factors and the characteristics of the dust its own, the dominantfactors are wind velocity, the type of the cargo and the moisture content of the dust.(2) Based on the collected data of wind tunnel experiments, it can be seen that thedispersion quantity is proportional to the power of the wind speed, namelyQ AVb;and has the negative power exponent relationship with the moisture content, namelyQ Ae wFor the case of coal, the inflection point of the relation between thedispersion quantity and the moisture content is about5%~6%, and the saturatedmoisture content is10%~15%. The factor of material type may be included into thespecific weight of the material.(3) The data of site measurements indicates that the comprehensive concentrationof the dispersion dust is proportional to the power of wind speed with the powerranging between1.2and2; the comprehensive concentration of dispersion dust isproportional to the negative power of the natural logarithmic constant e, and thenegative power is between-0.4and-0.1.(4) In site conditions, when the wind speed is greater than1m/s, the increasingrate of the dispersion dust concentration begins to rise up; when the moisture contentof the cargo is more than4%, the significance of the moisture content in the dustinginhibition began to lower down. The two indices are significant for dust controlling.