基于改善水流特性的超声波热量表设计

Design of ultrasonic heat meter based on water flow characteristic improvement

针对基表内水流分布是影响流量测量精度的关键问题,利用流体力学知识结合数值模拟分析,设计了一种基于改善水流特性的超声波热量表。通过对热量表DN25型基表内流场分析,在进水口中心线处安装一个圆锥体整流装置,采用圆滑立柱型的反射装置,有利于分流从而防止射流的产生;在测量管道前端增加一个"喇叭口"的导流构型和增大长径比,有利于流动发展完全,提高测量精度。通过Matlab软件仿真,对比基表优化前后的偏差曲线图证明所设计热量表的稳定性和精度都得到了提高,达到了预期的要求,具有广阔的市场前景。

Since the water flow distribution in base table is a key problem to affect on the flow measurement accuracy, the hydromechanics knowledge combined with the numerical simulation analysis is adopted to design an ultrasonic heat meter based on the water flow charaeteristic improvement. By analyzing the internal flow field of the DN25-type base table, a cone rectifier is installed on the center line of the water inlet and the reflection unit of smooth pillar type is adopted to facilitate the shunting and avoid the jet flow production. A ＂flared＂ diversion kerb configuration is added to the front end of the measuring channel and the length-diameter ratio is increased to benefit to the entire flow improvement and improve the total fluxion development. The deviation curve graphs before and after optimizing are compared by the simulation of Matlab software. The results prove that the stability and precision of the designed heat meter are improved, and the meter meets the expected requirements and has a broad market prospect.