一、引言临界流流量计由于其稳定性和重复性好、准确度高,被广泛用作标准流量计。但在实际使用中,相关参数均存在使用条件与标定条件不一致的情况,从而给使用带来一定误差。在JJG620-2008《临界流文丘里喷嘴》检定规程中规定,喷嘴应在使用条件下标定,否则应能使标定条件结果足够准确地换算到使用条件下,就说明了这一点。在实际工作中,业内人士做了许多尝试和探索,有资料证明在常温常压下,湿度变化引 I. INTRODUCTION The critical flow meter is widely used as a standard flow meter because of its good stability and repeatability and high accuracy. However, in actual use, the relevant parameters are inconsistent with the conditions of use and calibration conditions, resulting in a certain error to use. JJG620-2008 “critical flow Venturi nozzle” test procedures stipulate that the nozzle should be calibrated under the conditions of use, otherwise it should be able to calibrate the results of calibration conditions accurately enough to use conditions, to illustrate this point. In the actual work, the industry has done a lot of attempts and exploration, data prove that at room temperature and pressure, the humidity change