超声波测速仪的计算流体力学数值模拟研究

超声波测速仪是一种利用超声波发射接收装置，通过发射接收时间来计算来流速度的一种仪器装置.目前国内许多研究都关注在如何消除测速仪的测量误差上，对于模型结构对测量风场的影响研究较少.为了考察测速仪的测量精度，本研究以模型结构对测量区域风速的影响作为关注的重点，采用计算流体力学方法模拟了从低速到高速的不同来流风速下的绕流流场，计算出位于测速仪中心区域的速度分布和不同截面上的平均速度，以判断测速仪模型结构对中心测量区域风速的影响程度.该研究结果表明在测速探头平面内测量到的速度值，无论在低速和高速时均最为准确.采用计算流体力学数值模拟方法可为今后的测速仪模型设计和改造提供准确的依据.

Computational Fluid Dynamics Numerical Simulation of an Ultrasonic Velocimeter

An ultrasonic velocimeter is a device with ultrasonic transmitter-receiver to detect the time between transmission and reception of ultrasonic waves and to calculate the velocity of fluid flow. The current domestic studies mainly focus on how to eliminate the measurement errors, but spare little attention to the influence of the model structure on the measuring wind field. In order to investigate the accuracy of a model velocimeter, the impact of the model structure on the wind velocity in the measuring wind field was addressed, the computational fluid dynamics (CFD) method was used to simulate the flow fields of different incoming flows from low speed to high, and to calculate the velocity profiles in the central area of the velocimeter and the average velocities in different cross sections. Consequently, the interference effect of the model velocimeter structure on the velocity in the central area of measurement was evaluated. The research results show that the velocities measured on the plane at the tops of measuring balls are the most accurate in spite of low or high incoming flow velocities. Therefore, the CFD method is proved to be a powerful tool for the model design of high-accuracy velocimeters.