What are the reasons for local pressure loss in pneumatic conveying
? ? Inpneumatic conveyingOne issue is local pressure loss. Next, let the experts from Shandong Juheng Environmental Protection Equipment Co., Ltd. take you to understand the reasons for local pressure loss in pneumatic conveying. Overcoming local resistance will result in energy loss, which can be understood as local pressure loss. Therefore, if we know the cause of local resistance, we will know the cause of local pressure loss. In some pneumatic conveying devices, such as feeders, rotary feeders, elbows, unloaders, and dust collectors, they are all sources of local pressure loss.
? ?The reason for this resistance can be summarized as follows: during the transportation process, the solid boundary undergoes rapid changes (such as contraction, rotation, fragmentation, etc.), and expands or passes through local obstacles (such as gate valves) due to the rapid changes in the internal velocity, direction, and distribution of the fluid. This local resistance can be divided into two types. One is to change the direction of flow, but maintain the same flow velocity, just like flowing through an elbow. Another type is the change in flow velocity. In practical applications, this change is often caused by changes in the geometric conditions of the pipeline, resulting in changes in the distribution of fluid flow velocity, the influence of fluid micro mass, and mass exchange between the main flow and vortices. The changes are shown in Figure 1:
Figure 1
? ? There are various forms of local resistance in practical applications, such as: when the fluid passes through the expansion tube, it flows from a small section to a large section, the fluid particles do not suddenly rotate due to inertia, the fluid boundary gradually expands, and a vortex zone is formed at the expansion tube; The friction between particles in the vortex zone will consume some energy; During material exchange, friction and impact also consume a portion of energy; In addition, when the fluid enters a large cross-section pipeline, the velocity changes and the velocity distribution reorganizes, which can also interfere with the fluid's movement and consume energy. These energy losses are actually the essence of local resistance.
? ? ?In other forms of local resistance, elbows, reducers, or branch valves are essentially the same. Due to the adhesion of gas, but the local resistance coefficient is different in the calculation. In addition, the size of the vortex region is related to the magnitude of local losses. The larger the vortex area, the greater the energy loss. Therefore, to reduce the local pressure loss caused by local resistance, it is generally achieved by changing the geometric shape of the pipeline to avoid the impact of vortex zones and particles.
? ? ?Therefore, in pneumatic conveying, the design of pipelines and the selection of conveying equipment are very important parts, so it is necessary to find a professional pneumatic conveying manufacturer,Shandong Juheng Environmental Protection Equipment Co., LtdLooking forward to your call!