湿空气密度测算系统不确定度分配方法研究

Study of the Uncertainty Distribution Method in the Measurement System of the Density of Humid Air

为了确定湿空气密度等间接测量量的测量方案及测量仪表精度,阐述了湿空气密度等间接测量量的不确定度分配方法及流程,对干燥过程中某一具体案例进行计算分析。结果表明采用等作用原则将湿空气密度的不确定度平均分配到压力、温度和湿度三项直接测量量的不确定度中,易产生不合理的仪表精度要求,可根据实际情况进行调整。对于所计算的案例,建议将压力、温度和湿度不确定度分别调整至0.3%、0.8%和3%。该组不确定度指标既满足了对目标量湿空气密度的不确定度要求,又尽可能降低了成本。

The uncertainty distribution method of the indirect measured parameter was studied and elaborated in detail. The model of uncertainty distribution in the measurement system of the density of humid air was developed and applied in a typical test system. Analysis results show that the average distribution among the three related sub- items will lead to unreasonable accuracy requirements. According to the current level of the instrument accuracy,the uncertainties of the pressure,temperature and relative humidity are adjusted to 0. 3%,0. 8% and 3%,respectively. This set of uncertainty index can meet the final uncertainty requirement for the humid air density with an affordable and reasonable instrument cost.