出水管角度对网式过滤器内部流场影响研究

Influence of Outlet Angle on the Internal Flow Field of Screen Filter

以全自动网式过滤器为研究对象,基于Fluent软件,用多孔阶跃模型模拟滤网,采用Realizable k-ε湍流模型对其内部流场进行了数值模拟。结果显示数值计算与物理试验的进出口压降相对误差为6.77%,说明选择的数学模型具有一定的准确性和可靠度。在此基础上,分析了过滤器内部流场,发现压降发生的部位主要为滤网;出水管内速度、压强分布不均匀,有漩涡区存在。在保持滤网面积不变的情况下,分别模拟了出水管与罐体夹角α为75°、60°、45°、30°时过滤器的流场,结果表明:夹角α对出水管内流场影响较大。随着夹角α的减小,出水管上部流速、压强分布均趋于均匀;出水管左侧漩涡区域逐渐消失,右侧漩涡区域有所增大,但对进、出口压降及其他部位的流场影响较小。出水管与罐体夹角α并不是影响过滤器流场的主要原因,若要对过滤器进行结构优化,需从滤网着手。

In this study, the Fluent software is used to simulate the internal flow field of the automatic screen filter by porous jump model and Realizable k-8 model. The difference of the inlet and outlet pressure drop between the numerical simulation result and the physical experiment result is 6.77%, which indicates that the numerical simulation is accurate. After analyzing the filter internal flow field, it is found that the main pressure drop part is filter screen; some vortex zones exist in the outlet pipe, the distribution of velocity and pressure are uneven; under the condition of unchanged filter area, the flow fields of the filters with the outlet pipe and tank angle of 75°, 60 °, 45 °, 30 ° are respectively simulate. The results showed that： the angle α-has a greater influence on the flow field of outlet pipe, but has little effect on other area as well as the pressure drop between the inlet and outlet. With the decrease of the angle or, the distribution of velocity and pressure of the upper outlet pipe are more uniform; the vortex on the left of the outlet pipe disappears gradually, but the vortex on the right of the outlet pipe increases gradually; the angle between the outlet pipe and tank is not the main reason affecting the flow field, so structural optimization should be carried out from the filter screen.