New equation and algorithm are developed for non-iterative calculating flowrate of fluid energy carrier for pressure differential flowmeter based on long radius nozzle. This equation implicitly contains three build-in iterative cycles for calculating flowrate. According to the results of comparing the flowrate values obtained by developed non-iterative algorithm to the flowrate values by standard iterative algorithm, the authors found that the developed non-iterative algorithm ensures the accuracy of flowrate calculation specified by the requirements of DSTU GOST 8.586.5:2009.
A new methodology for designing the differential pressure flowmeters for fluid energy carriers has been developed in order to provide the minimum uncertainty of flowrate measurement results. This methodology is implemented in “Raskhod-RU” CAD system for the computer aided design and calculation of differential pressure flowmeters. “Raskhod-RU” CAD meets the requirements of new Standards (DSTU GOST 8.586.1,2,3,4,5-2009 and GOST 8.586.1,2,3,4,5-2005).