Estudo do comportamento hidrodinâmico de medidores de vazão de gás liquefeito de petróleo utilizado a teoria do elemento de pá com efeito de grade

Abstract

Turbine flowmeters are widely applied in industry to quantify transferred amounts of liquid products, even for commercial purposes, due to its high accuracy and large operational range. The development of engineering computational tools to analyze and improve performance of such meters offers to the engineer the possibility of contribution to society, increasing quality of measurements and minimizing distortions in supply chain potentially harmful to final consumers. Most turbine flowmeters have several blades, becoming the determination of lift and drag coefficients still challenge. This makes cascade effect indeed relevant, without which the performance of the turbine can be overestimated by the Blade Element Theory (BET) analysis. Hence, the present work proposes the application of BET to the analysis of hydrodynamic behavior of turbine flowmeters applied to Liquefied Petroleum Gas (LPG) measurement. The proposed model calculates the cascade effect correction due to the local solidity throughout turbine blades length, in order to accurately predict lift and drag coefficients at each blade section. Operational parameters of the studied equipment are obtained from the proposed computational model and compared to the field performance of an existent measurement system for several conditions within the operational range, revealing satisfactory coherence. For this analysis, computational fluid dynamics (CFD) techniques are employed, through the finite volume method. For validation of the CFD model, computational results are compared to in-situ data acquired during regular operation of the measurement system. Cavitation susceptibility is also evaluated through the CFD model, in order to provide indication of boundary limits inside which operational conditions are maintained within specifications. As a result, the study indicates that turbine flowmeter performance can be predicted by the proposed computational modeling strategy based on the BET analysis and field results of angular velocity and linearity can be accurately reproduced.