Application Of Measurement Data Processing Method For Measuring Sonic Nozzle Gas Flow Standard Device

The purpose of measurement is to obtain measurements, but in many cases only measurement results are given are often not fully. Any measurement defects, all the results will be more or less deviation from the true value is measured, the measurement results are given at the same time, also must be reliable degree also pointed out that the measurement results.Measurement data in this paper for sonic nozzle gas flow standard device, device using vacuum sonic nozzle method. According to the principle of fluid mechanics, when the nozzle upstream stagnation pressure constant, gas in the subsonic, laryngeal airflow velocity with throttle pressure than the p1/PO decreases. When the throttle pressure than the p1/PO to a certain value, throat velocity will reach the maximum velocity (speed), namely the so-called critical velocity. The principle of the nozzle can be used as a standard list, select a different combination of calibration nozzle, different flow values.The device on the same by the measurement repeated in the measurement of the prescribed conditions, and the difference value of measuring results for minus standard measurement reproducibility, we estimate for the system error.Influence of the sources of the uncertainty of measurement is the influence on measurement results, determine the sources of the measurement is not missing, don’t repeat the calculation, especially of the component uncertainties for various big.The measurement uncertainty of the most fundamental difference lies in the degree and measurement error, uncertainty is an interval, it may be said measured value distribution range, is related with the measurement results with parameters, and error is a difference, the difference between the measurement results and the standard measurement reproducibility of the values of quantities, the fundamental difference caused by the difference in other aspects.