摘要
用有限元法(FEM)和粒子图像测速技术(PIV)对三种不同开口度下进口节流滑阀沿进口流道、节流口、阀腔以及出口流道的流场进行了数值计算和试验可视化研究。数值模拟的数学模型采用的是连续性方程和Navier-Stokes方程的流函数—涡量式,有限元法用于方程的离散。自行编制的有限元计算程序用来计算求解区域离散点上的流函数及涡量值,再根据流函数及涡量与速度分量之间的关系求出各结点上的速度矢量。对于粒子图像测速试验,光源采用双脉冲Nd:YAG激光器,再用柱透镜和球面镜调制得到1.0mm片光照射流场。30～50μm的聚苯乙烯小球用做示踪粒子,Kodak ES1.0 CCD照相机拍摄流场图像,所得图像用FFT相关算法进行处理,结果用Tecplot输出,数值计算和PIV试验表明,滑阀内部有三个部位产生涡旋。数值计算又表明滑阀开度对阀内部流场结构有影响。研究对于定性分析阀内能量损失、噪声以及对阀的结构和流道的设计有重要实际意义。
The finite element method (FEM) and particle image
velocimetry (PIV) technique are utilized to get the flow field
along the inlet passage, the chamber,the metering port and the
outlet passage of spool valve at three different valve openings.
For FEM numerical simulation, the stream function ψ-vorticity
ω forms of continuity and Navier-Stokes equations are empl-
oyed and finite element method is applied to discrete the
euqations.Homemade simulation codes are executed to compute
the values of stream function and vorticity at each node in the
flow domain, then according to the correlation between stream
function and velocity components,the velocity vectors of the
whole field are calculated. For particle image velocimetry
experiment,pulse Nd: YAG laser is exploited to generate laser
beam, cylindrical and spherical lenses are combined each other
to produce 1.0 mm thickness laser sheet to illuminate the object
plane, Polystyrene spherical particle with diameter of 30～50
μm is seeded in the fluid as a tracing particles, Kodak ES1.0
CCD camera is employed to capture the images of interested,
the images are processed with FFT cross-correlation algorithm
and the processing results is displayed by Tecplot. Both results
of numerical simulation and PIV experimental show that there
are three main areas in the spool valve where vvrtex is formed.
Numerical results also indicate that the valve opening have
some effects on the flow structure of the valve. The
investigation is helpful for qualitatively analyzing the energy
loss, noise generating,steady state flow forces and even
designing the geometry structure and flow passage.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2004年第6期10-18,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(60374042)
关键词
流场
进口节流滑阀
有限元法
粒子图像测速
Flow field
Spool valve
Finite element method(FEM)
Particle image velocimetry(PIV)
