Local pressure loss in the blast furnace dust collector system

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This post was last edited by li*ch1968 on 2011-8-30 at 10:22. In a blast furnace dust collector system, when dust-laden gas flows through the components and equipment of the ductwork, local resistance is generated as a result of eddies that occur due to changes in the direction of airflow, variations in the cross-sectional area, and changes in flow rate. The energy loss caused by overcoming local resistance is called local pressure loss. 　　Components in the blast furnace dust collector system that generate local resistance mainly include dust collection hoods, elbows, reducers, tees, air flow control valves, and air outlets. The local drag coefficient values for most accessories are determined experimentally. When using the local drag coefficient to calculate the local pressure loss, the flow velocity and dynamic pressure corresponding to the experiment must be employed. 　　It should be noted that the local pressure loss in the blast furnace dust collector system occurs along the length of the dust collection pipes, and it cannot be separated from the frictional losses. To simplify the calculations, it is assumed that the local pressure loss is concentrated on one cross-section of the fitting, with friction losses being ignored. Friction losses must only be considered for fittings of considerable length. Typically, the friction loss of a fitting is calculated by measuring the length of the dust removal pipeline from the center of one fitting to the center line of the next fitting. For those paired components that are close to each other, the flow pattern of the air entering the subsequent component differs from the conditions governing the flow pattern used to determine the local pressure loss. When this happens, it is not possible to use these drag coefficient values.