微小尺度射流流量传感器的设计与仿真分析

Design and Simulation Analysis of Microscale Fluidic Flow Sensor

在许多新型传感器和微系统中均存在微量流体自动、精确地驱动和控制问题,而这有赖于微小尺度下对流量的精确测量。基于射流振荡原理设计了一种新型的无反馈通道微小尺度流量传感器,采用计算流体动力学(CFD)方法对该流量传感器的测量特性进行了仿真研究。通过观测振荡腔内部流场,分析了振荡器内部流动形态和射流振荡过程。通过对监测点压力变化曲线的分析,获得了不同入口速度下流体振荡频率,建立了流体流速与振荡频率的函数关系。研究结果表明,该微小尺度射流振荡器振荡平稳,主射流切换灵活,在较宽的流速范围内,流速与振荡频率具有线性关系,具有0.3%的较低的相对压力损失并可达到较小的测量下限,易于加工成型。

The accurate driving and automatical control of micro-fluid exists in many sensors and MEMS,which relies on the precise flowrate measurement in microscale.A new fluidic oscillator without feedback channel is proposed as the flowrate sensor in microscale tubes.A computational fluid dynamics（ CFD） method is employed to study the measurement characteristics of the flow sensor.The inner flow distribution and oscillating procedure in chamber are analyzed qualitatively through the investigation of flow fields.The oscillation frequencies are obtained under different inlet velocities by the analysis of the pressure fluctuation in the preset points and then the functional relationship is established between the flow velocity and oscillation frequency.Simulation results indicate that the microscale fluidic flow sensor oscillates stably and the main jet switches side by side flexibly.The linear relationship between velocities and oscillation frequency can be obtained in a relatively wide measurement range,and the sensor has 0.3% relative pressure loss,the small lower measuring limitation and fabricates easily.