基于质量流量法的透气度流量盘测量方法的建立与应用

为解决体积流量法在测量透气度流量盘时容易受环境因素影响、流量盘两端压差不稳定等问题, 基于质量流量法建立了一种透气度流量盘测量方法。该方法采用质量流量端子与控制器相结合的方式获得流量盘的质量流量, 并通过计算将质量流量转换为体积流量；基于LabVIEW软件搭建控制系统, 实现对流量盘两端压差的自动反馈调节, 将压差稳定在设定范围内；采用不同规格流量盘对该方法的重复性和稳定性进行测试, 并与体积流量法和国际共同实验进行对比。结果表明:①质量流量法与体积流量法相比, 二者测量结果的变异系数集中分布在0.2%左右, 相对极差分布在1%左右, 具有相近的重复性和稳定性；②质量流量法与国际共同实验相比, 二者测量结果的变异系数整体分布在0.2%左右, 相对偏差多数分布在1%左右, 最大相对偏差为1.91%, 具有较好一致性。该方法能够对流量盘实现稳定、准确测量, 并为提高测量装置的自动化水平提供支持。 

Mass flow-based air permeability standard measurement method

To avoid the influences of environmental factors on the air permeability standard measurement and the variation of pressure drop across the standard in volume flow method, a method based on mass flow was established. The method combines the mass flow element with a controller to obtain the mass flow through the standard and converts the mass flow into the volume flow by calculation. A control system was developed on the basis of LabVIEW software to regulate the pressure drop across the standard and keep it within the set range. The repeatability and stability of the established method were tested with air permeability standards of different specifications, and the data were compared with those of volume flow method and international collaborative experiments. The results showed that: 1) The coefficients of variation of the measurement results of mass flow method and volume flow method distributed around 0.2%, and their relative extreme difference around 1%. The two methods had similar repeatability and stability. 2) The coefficients of variation of the measurement results of mass flow method and international collaborative experiments distributed around 0.2%, their relative deviation distributed around 1% and their maximum relative deviation was 1.91%. The two showed pretty good agreement. The established mass flow method can measure air permeability standard stably and accurately, it provides a support for improving the automation of measurement devices.