Abstract:

During the experiment using the gas delivery system, the actual flow rate often deviates, and the deviation value is different under different inlet pressures and system pressure differences, which will affect the accuracy of the experimental results in certain cases. The experimental results can be corrected by error prediction. This research uses a nitrogen conveying system to analyze and predict errors by varying the inlet pressure, differential pressure, and flow rate value and range and measuring the actual flow rate. It is shown that the system differential pressure has less effect on the flow control. And the increase of inlet pressure needs to be used with the back pressure valve thus improving the accuracy of the system, so the inlet pressure can be increased to make the deviation value smaller. Meanwhile, a universal prediction model of error value and flow rate value is proposed based on the theoretical derivation and experimental results, which can accurately predict the actual flow rate, and provides a new idea for the error analysis and precise control of a gas conveying system.

Key words: gas, pneumatic conveying, measurement, mass flow meters, error analysis, flow control

摘要：

使用气体输送系统进行实验过程中时常会出现实际流量发生偏差的现象，并且不同入口压力和系统压差下其偏差值大小不同，一定情况下会影响实验结果的准确性，可通过误差预测对实验结果进行修正。以氮气输送系统为例，通过改变入口压力、压差和流量大小与范围并测量实际流量，进行误差分析和预测。研究结果表明，系统压差对流量控制的影响较小，而入口压力的增大需要配合背压阀的使用从而提高系统的精度，因此可以增加入口压力使偏差值更小。同时，根据理论推导和实验结果提出了普适的误差值与流量值的预测模型，可准确预测实际流量，为气体输送系统的误差分析与精准控制提供了新思路。

关键词: 气体, 气力输送, 测量, 质量流量计, 误差分析, 流量控制