热式气体质量流量计动态响应的优化

Optimization of Dynamic Response of Thermal Gas Mass Flowmeter

针对热式气体质量流量计测量过程中动态响应时间过长的问题,重点研究了在流量发生变化时探头及附近气体的传热机理,得出了响应过程中的时间常数随质量流量变化的规律,总结出了时间常数的数学模型。将时间常数随质量流量变化的规律与流量计实时的测量值进行迭代,在热式测量流量值稳定之前,提前预测出稳态时的质量流量。通过实验证实了上述模型和方法,提前预测出稳态时的流量,在质量流量在55 kg/h~287 kg/h范围内,能够使响应时间缩短了80%~90%。

Aiming at the problem of excessively long dynamic response time during the measurement of thermal gas mass flow meters,the focus is on the heat transfer mechanism of the probe and nearby gas when the flow changes,and the law of the time constant changing with the mass flow during the response process,Summed up the mathematical model of the time constant.The law of the time constant changing with the mass flow rate is iterated with the real-time measured value of the flowmeter,and the steady-state mass flow rate is predicted in advance before the thermal measurement flow rate stabilizes.The above models and methods are verified through experiments,and the steady-state flow rate is predicted in advance.When the mass flow rate is in the range of 55 kg/h~287 kg/h,the response time can be shortened by 80%~90%.