真空泵对测量空气相对压力系数的影响

实验室利用差压传感器测量空气相对压力系数时,真空泵的抽真空度对于实验结果有很大的影响。实验采用控制变量法,对真空泵抽真空度这一影响因素进行了研究。结果表明,真空泵抽真空程度越高,测量所得空气相对压力系数值越小,并且越接近其真实值,空气相对压力系数测量值的改变量随真空度的增大而不断减小,二者之间呈现出一条斜率渐渐减小的曲线关系。真空泵无法完全抽真空时,可以通过将最终测得的空气相对压力系数值乘以其对应真空度值的方法对实验结果进行修正。

The influence of the vacuum pump on the air relative pressure coefficient

The air relative pressure coefficient should be a regular value,but in the laboratory,the results of the air relative pressure coefficient measured by silicon-based piezoresistive pressure sensor changes when the input voltage changes.Searching the working principles of the pressure sensor,there are four reasons： first,the cacuous extent of the vacuum pump;second,the dry level of the glass bubble;third,the initial input voltage of the pressure sensor;forth,the volume change of the glass bubble and the temperature disparity of the gas in the duct.This experiment searches the influence of the vacuum pump.The results showed that the higher the cacuous extent of the vacuum pump,the smaller the relative air pressure coefficient and the closer to its true value.