| 英文摘要 |
The volumetric flow rate of complex flow field in duct was experimentally investigated in this project. The standards about the measurements of gas volumetric flow rate in duct built by United States Environmental Protection Agency (US EPA) were preliminarily collected and studied. The volumetric flow rate of complex flow in duct can be measured by two-dimensional and three-dimensional probes. The two-dimensional and three- dimensional probes are Type S Pitot tube and five-hole prism- shaped probe, respectively. The calibration techniques of the two-dimensional and three-dimensional probes and the operating procedures of measuring volumetric flow rate were developed in accordance with the US EPA standards. The calibration coefficients and curves of the probes were calibrated by a standard wind tunnel qualified by US EPA standards. Three industrial ducts were selected. The gas volumetric flow rate of these three industrial ducts was measured by the calibrated probes. By analyzing the experimental results of the calibrations and industrial measurements, the difference in the measurement of gas volumetric flow rate between two-dimensional and three-dimensional probes was discussed. The operating procedures of the probe calibration and gas volumetric flow rate measurement were written. Each probe shall be calibrated prior to use according to the procedures in section 10 of US EPA Method 2G. Manufacturer-supplied calibration data shall be used as example information only, except when the manufacturer calibrates the probe as specified in section 10 and provides complete documentation. The probes are calibrated according to the following requests: (1) examine the physical appearance and dimensions of the probes, (2) wind tunnel specifications, (3) resolutions of protractors, (4) resolutions of differential pressure gauges, (5) sampling conditions of data acquisition system, and (6) completely performing calibration procedures. The gas volumetric flow rate in duct measured by the calibrated probes is performed by the following procedures: (1) consideration of measurement sites, (2) arrangement of traverse points, (3) considering sampling conditions of data acquisition system, (4) calibration of measuring devices, and (5) precise measurement of yaw angle.
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