The Numerical Simulation And Optimization Of The Averaging Pitot Tube

As a typical Averaging Pitot tube, the Veris bar has been widely applied in industrial field. The tube has advantages of simple structure, high measuring accuracy, especially lower permanent pressure loss and remarkable energy-saving effect. However, the tube has a low differential pressure which could cause a high uncertainty when the sensor is subjected to vibrations and sometimes a pulsating signal is received. Moreover, the flow coefficient of the tube is unstable when the Reynolds number of the fluid is very low, so the tube has a low accuracy when measuring the fluid with low Reynolds number. All these disadvantages restrict the promotion of the Averaging Pitot tube.The paper investigated the measuring process of the Veris bar which is a typical spoiler problem. In order to enlarge the differential pressure and measuring range ratio of the tube at a low cost at the stability of the flow coefficient and permanent pressure loss, the paper used flow control technology to influence the conversion between dynamic pressure and static pressure. The paper innovatively designed a new averaging pitot tube with better accuracy and larger measuring range ratio.All the investigations were based on the investigation of grid and turbulent model. The paper could be mainly divided into four parts. Firstly, the paper studied the section angle of the tube to see how it influences the differential pressure, and then find an optimized angle that could enlarge the differential pressure. The investigation of the section angle showed that the differential pressure and measuring range ratio could only increase a little when only optimize the section angle. To increase the differential pressure more effectively, the paper innovatively established a two-profile Averaging Pitot tube based on the Venturi effect. The new sensor was constructed by two profiles which have the same section, the interactions between the two profiles influence the conversion between the dynamic pressure and static pressure. The paper investigated the relationship between the velocity and flow coefficient by numerical simulation. Thirdly, the paper investigated the influences of pipe diameter have on the flow coefficient as a foundation of the promotion of the new tube.All the results of the investigation showed that, comparing to the original Veris bar the two-profile averaging tube could offer much more differential pressure and larger measuring range ratio. The new tube could be well implied in practice.