蝶阀流场的数值模拟及涡结构分析

Numerical Simulation and Vortexes Structure Analysis of Butterfly Valve Flow Field

利用流体动力学软件Fluent对双偏心蝶阀不同开度下的流场进行三维稳态数值模拟计算,得到了不同开度下阀后压力场和速度场的分布规律。结果表明:由于射流卷吸作用,在蝶板背面出现一个负压区,且开度越小,负压区的真空度越大。同时,根据模拟计算的结果,应用Q判据对蝶板下游流场涡旋结构进行识别及分析,证实了流体经过蝶阀后,在蝶阀下游形成一对柱状类似迪恩涡的二次流涡旋。涡旋以螺旋状向下游运动,由于边界层涡量的补充,涡旋经历了一个稳定发展的阶段,最终由于流体的粘性耗散而逐渐衰减直至破裂。

Three-dimensional steady flow field of double eccentric butterfly valve were numerically simulated using CFD software Fluent under different opening angles.The pressure and velosity in the flow field were figured out at different opening angles.The results indicate that because of the role of jet entrainment,a negative pressure area appears on the back of the butterfly plate and the smaller opening angles are,the greater vacuum degree in the negative pressure zone is.In addition,according to the simulation results,vortexes structure in downstream flow field of the disc was identified and analyzed by Q criterion,it is confirmed that a couple of secondary flow vortexes appear in the downstream of the disc which are similar to dean vortexes when fluid through the valve.And the vortexes continues to move downstream with a spiral-shaped, due to the complement of vorticity in the boundary layer,the vortexes experiences a stable development stage, eventually the vortexes are decayed and collapsed because of viscous dissipation.