pVTt法气体流量国家基准装置温度分布特征及流场动态预测技术研究

pVTt gas flow device is the highest national standard of gas flow measurement traceability in our country. But there are some existing problems like large uncertainty on temperature measuring and low calibration efficiency. This project will use CFD calculation and experimental confirmation methods to investigate the pVTt calibration processes. Firstly, various unsteady processes during the calibration such as containers vacuum-pumping, rarefied gas flow field uniformity, gas flowing at sonic state through nozzle and turbulent flow process after charging will be calculated. Secondly, a precise flow field predicting algorithm for constant vlolume charge and discharge will be proposed based on CFD results and a large number of experimental data. According to this prediction algorithm and dynamic data of many sensors, the predition of steady state of gas flow field distribution and flow rate calculation could be realized, hence the calibration time could be greatly shorten and the calibration efficiency could be improved a lot. Based on the distribution characteristics of temperature field, temperature measurement points scheme of the pVTt verification containers and the average temperature algorithm could be optimized. As a result, the uncertainty of temperature measurement could be reduced and and the accuracy of flow measurement will be improved. This project is based on matured theoretical knowledge and experimental methods. While the research ideas are innovative and its solutions are clearly claritied. Thus, it will be of great significance to improve our national gas flow measurement level and calibration efficiency.

pVTt法气体流量标准装置是我国气体流量量值溯源的最高标准，现有装置存在温度计量不确定度大以及流量检定效率低下等问题。本课题采用CFD计算与实验验证的方法对pVTt法检定过程开展研究。对检定过程中容器抽真空、稀薄气体的流场均匀、临界流喷嘴音速状态进气以及进气后气体的湍流流动等多工况进行非稳态流场计算。结合大量的实验样本数据，提炼精确的定容充放气流场动态预测算法，基于此算法和充放气后多传感器的动态数据，实现气体流场稳态分布的预测和流量计算，从而极大缩短等待流场均匀的时间，提高检定效率；基于温度场分布特征，优化pVTt检定容器内的测温点布置方案以及平均温度算法，减小温度计量的不确定度，提高流量计量精度。课题在理论知识和实验手段上都有成熟的基础，研究思路新颖、方案明确，其成功开展对于提高我国气体流量的计量水平和检定效率有较为重大的意义。

pVTt 法气体流量标准装置是我国气体流量量值溯源的最高标准，现有装置存在温度计量不确定度大以及流量检定效率低下等问题。本课题采用CFD 计算与实验验证的方法对pVTt 法检定过程开展研究。对检定过程中容器抽真空、稀薄气体的流场均匀、临界流喷嘴音速状态进气以及进气后气体的湍流流动等多工况进行非稳态流场计算。结合大量的实验样本数据，提炼精确的定容充放气流场动态预测算法，基于此算法和充放气后多传感器的动态数据，实现气体流场稳态分布的预测和流量计算，从而极大缩短等待流场均匀的时间，提高检定效率；基于温度场分布特征，优化pVTt 检定容器内的测温点布置方案以及平均温度算法，减小温度计量的不确定度，提高流量计量精度。在《Flow Measurement and Instrumentation》等国内外知名期刊共发表论文10篇，申请专利2项，培养研究生4名，参加Flomeko等国际会议2次。通过三年左右的研究，课题组在气体流量计量方面有了更为坚实的基础，课题的相关成果其成功开展对于提高我国气体流量的计量水平和检定效率有较为重大的意义。