The measuring system for air mass flow rate determination - difficult measuring conditions - case study

Abstract

Accurate gas flow measurement is required in many industrial applications. In typical circumstances the most reliable option is the use of single-hole orifice flowmeters, which characterize with the simplicity of the construction, lack of moving parts and high accuracy. However, such devices require long straight duct sections in order to perform the proper measurement. Sometimes on existing installations, where the space is limited, there is no possibility to fulfill these requirements. Such problem appeared in power plant in Opole. Multi-hole orifice flowmeters can be a reasonable solution in this particular case. Due to their enhanced resistance to flow disturbance they require shorter duct sections and could provide a correct measurement. The paper presents the results of the numerical analysis of air flow in 6-hole orifice flowmeter. The calculations were performed for the existing duct geometry from power plant in Opole. The orifice pressure drop was estimated for a wide range of Reynolds number. The analysis of the numerical results showed that multi-hole orifice flowmeters can be used in investigated situation. The results of experimental measurements performed in Opole power plant are also included in the paper.