부산대학교 도서관

As a primary standard device, the pVTt method gas flow standard device is widely used and has been used as the main gas flow standard in many countries. Chongqing Branch of National Oil and Gas Large Flow Metering Station has established a set of pVTt gas flow standard device with working pressure of (0.1~1.2) MPa, flow range of (14~850) kg/h, Measurement uncertainty of $U_{\mathrm{r}}=0.07\%$ and $k=2$. The device uses a 2m 3 tank as the standard container and uses 1.2 MPa natural gas stored in two 3300m 3 spherical tanks upstream as the calibration gas. The advantage of this device is that it can operate under positive pressure using natural gas as the medium, and the upstream natural gas source pressure is relatively stable and the gas quality is clean, without the need for additional stabilizing and purifying devices. This device can perform calibration of critical flow Venturi nozzles, mass flow meters, and other gas flow meters with an accuracy level of 0.2 or below under positive pressure using natural gas as the medium. Using this detection standard device, a critical flow sonic nozzle with a throat diameter of $\mathrm{d}=4.770\text{mm}$ was calibrated and the uncertainty of the measurement results was analyzed, resulting in $U_{\mathrm{r}}=0.16\%$ and $k=2$.