Approximate solution for discharge coefficient of the sonic nozzle with surface roughness. (December 2016)

• Record Type: Journal Article
• Authors: Ding, Hongbing; Wang, Chao; Wang, Gang
• Is Part Of: Flow measurement and instrumentation. Volume 52(2016:Dec.)
• Page Start: 227
• Page End: 232
• Publication Date: 2016-12
• Subjects: Discharge coefficient -- Sonic nozzle -- Equivalent sand roughness -- Average roughness -- Turbulent boundary layer; Fluid dynamic measurements -- Periodicals; Flow meters -- Periodicals; Fluides, Dynamique des -- Mesure -- Périodiques; Débitmètres -- Périodiques; 681.2805
• DOI: 10.1016/j.flowmeasinst.2016.10.013
• Languages: English
• ISSNs: 0955-5986

Abstract

Abstract: Sonic nozzle is widely used in the flow measurement and control. Nowadays, it has been applied to higher Reynolds number flow increasingly. The effect of surface roughness on discharge coefficient of the sonic nozzle should be discussed. An approximate analytic solution for discharge coefficient of the sonic nozzle with surface roughness was proposed in detail. The determination of this coefficient was based on universal logarithmic velocity-distribution law and the principle of equivalent velocity profile. Although there are some apparently approximations, this algebraic method accurately predicts the discharge coefficient of the sonic nozzle with surface roughness in Reynolds number range from 10 4 to 10 9, a relative equivalent roughness range of 10 −6 to 10 −2 . Some experiments of sonic nozzle conducted by others showed agreement with present algebraic method. Besides, the agreement between this method and the corresponding exact numerical calculation is also good. The present method provides an excellent tool to deeply investigate the roughness effect and promote further improvement of the standard. Highlights: Approximate solution for discharge coefficient of sonic nozzle with roughness. Universal logarithmic law and principle of equivalent velocity profiles were used. Experiments conducted by others showed agreement with present algebraic method. The agreement between this method and exact numerical calculation is also good.