Differential pressure flow measurement method based on variable area regulating valve

Compared to traditional differential pressure flowmeters, the flow measurement method based on a control valve requires no additional throttling device and has a larger range ratio. Through experiments, the flow-pressure difference relationship between the gas and liquid phases under different valve openings was studied, and a measurement model was established for flow rate, pressure difference, and valve opening. The model was then used to derive calculation formulas for the mass flow rates of water and air. Validation results indicate that the relative error of the water mass flow calculation formula remains below 5% for 93.8% of the data points, while the gas mass flow calculation formula achieves a relative error of less than 5% for 92.9% of the data points, confirming its suitability for engineering applications. Within the tested experimental conditions, the turndown ratios for measuring water and air flow rates, both within a 5% error margin, reach 1 : 23 and 1 : 14, respectively. These results validate the practicality and reliability of using a variable area regulating valve for differential pressure-based flow measurement, offering a promising alternative for industrial flow metering systems.