pVTt法气体流量标准装置是我国气体流量计量的原级标准之一,其计量准确度不仅受温度传感器性能影响,与测温点的布置方案也有明显关系。本文研究的pVTt法装置,标准容器的容积为26 m3,工作原理为常压进气法。标准容器内安装有搅拌风机和导流风道,以减少温度场稳定时间并提高温度场均匀程度。装置采用35个精密铂电阻作为温度采集元件,将各测温点数据的算术平均值视作测量的平均温度。论文针对该装置建立CFD仿真模型,开展标准容器内温度场特性的非稳态仿真研究,针对等体积划分和均匀布置两种方案进行对比分析。结果表明,两种方案都能较准确地测量容器平均温度,但等体积方案在流场稳定后期波动更小,其与平均温度的差值最大不超过0.003 K。%pVTt gas flow standard is one of the national standards of the gas flow in our country. Its temperature measuring accuracy is not only affected by the accuracy of temperature sensors, but also affected by the layout scheme of these temperature sensors. The studied pVTt device with a 26 m3 collection tank operates under negative pressure. A stirring fan and a diversion duct are installed in the collection tank,so that the temperature stabilization time could be reduced and its non-uniformities decreased. 35 temperature sensors are employed in the device,and their average is arithmetically taken to obtain the mean temperature of the collected gas. In this paper,the CFD sim-ulation model is established for the device to carry out unsteady simulation of the temperature field of the collection tank. Then the measuring results of both equal-volume divided layout scheme and evenly arranged scheme are ana-lyzed respectively. The results show that both the two schemes can reflect the mean temperature of the tank,but the value of the equal-volume divided scheme fluctuates less during the late stabilization stage, where the maximum difference is no more than 0.003 K.
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