针对不同开度下U型节流阀内部流场的变化,基于软件COMSOL Multiphysics建立CFD数值计算模型，得到了节流阀内部流场的速度、压力分布等随着阀口开度变化的特性云图。研究结果表明：节流口处压力下降梯度较大，并出现局部低压区。阀内流体速度在经过阀口处急剧变化，阀口附近流速达到最大，并沿流体流动方向形成一个空心锥形高速射流区域。即流体出口端射流出射方向倾斜指向出口，另一过流面中流体出射方向指向阀座，并沿阀体壁面流动。此外，随着阀口开度减小，阀口处速度大小和阀口附近压力几乎不变，但是节流口流体出射方向角度变大。

A CFD numerical calculation model is established in order to study the flow field inside the Ushaped throttle valve with different opening degrees .The velocity, flow rate and pressure drop in throttle with different valve openings are also got. The research results show that the pressure drop near orifice is largest and a low pressure area also appears. When the flow passes through the orifice, it will be accelerated on the curved edge instead of going straight. The direction of this highspeed jet near the orifice is towards the exports. Furthermore, with reducing valve opening degree, the velocity and pressure drop near the orifice of the Ushape throttle valve almost keep constant, but the angles of jet become larger than before.