The Research Of Calibrating Large-diameter Gas Flow-meter Base On Wind Tunnel

Wind tunnel device produces stable and adjustable air flow by controlling the fan. Types of transmitter, installed in different location of calibration system, accurately measured various physical parameters related to flow, such as temperature, differential pressure, absolute pressure and so on. After correction of algorithm in software, we can calculate precise gas flow rate and take it as standard, which can realize the gas flow meter calibration. This thesis takes DHS-600* 600/1050* 1050-? annular low speed wind tunnel device of measurement institute in Anhui province as the research object, and use this pneumatic device to study large diameter gas meter calibration. It mainly discusses the following several aspects:1. With the method of computational fluid dynamics (CFD), the research base on simulation of the research object's wind tunnel structure and flow field, verify whether its related characteristics are conform with the standard for a model testing gas flow-meter.2. Measure the main flow quality of wind tunnel device. After the installation and adjustment, all the flow qualities must be tested. Therefore, this thesis mainly discusses the flow qualities which impact on flow-meter checking, including the axial static pressure gradient, turbulence intensity, wind energy ratio, maximum wind speed, minimum stable wind speed and velocity pressure stability. It verifies the performance of the wind tunnel whether meets the design requirements after the installation and adjustment by the analysis of experimental data.3. Large-diameter gas flow meter calibration validation studies. Comparative tests carried out wind tunnel apparatus and a gas flow meter calibration standard means to obtain the correction coefficient wind tunnel apparatus, verify its reliability. Problem of wind tunnel used for large-diameter gas flow calibration tests were analyzed to explore the level of accuracy and uncertainty issues tunnel device.4. Study the wind tunnel calibration of large diameter gas meter error analysis, including sources of error and correction method.