Dynamical Nuclei Measurement: On the Development and the Performance Evaluation of an Optimized Center-Body Meter

Abstract

This work is concerned with the development of a center-body venturi for nuclei measurements of novel design, the Venturix. Our project aims to: 1. Define a specially tailored geometry for cavitation nuclei measurement. This design study takes into consideration the following main aspects: the venturi mean flow in subcavitating regime, the viscous effects, the bubble dynamics. 2. Evaluate the performance of the meter: After testing the proposed design concepts, the venturi operating characteristics, in particular its operational limits, are assessed. Finally, the performance of the acoustic method used for detecting and counting the active nuclei in the venturi is discussed. / Vol. 119, DECEMBER 1997Copyright © 1997 by ASME Transactions of the ASME Downloaded From: http://fluidsengineering.asmedigitalcollection.asme.org/ on 09/18/2013 Terms of Use: http://asme.org/terms Transactions of the ASME Downloaded From: http://fluidsengineering.asmedigitalcollection.asme.org/ on 09/18/2013 Terms of Use: http://asme.org/terms

Effect of gas content on cavitation nuclei

“…The analytic results can now be used in conjunction with the experimental values obtained in Venning et al (2018) for cumulative background nuclei distributions C as a function of critical tension. The measurements are obtained using a CSM (Pham, Michel & Lecoffre 1997;Khoo et al 2016) at the Australian Maritime College (AMC) cavitation tunnel. Furthermore, figure 7 shows a combined plot of C versus Δp cr , the bubble diameter obtained analytically using (7.10) being given on the top horizontal axis, and a power-law fit is given by There are three things to note here.…”

“…(2018) for cumulative background nuclei distributions as a function of critical tension. The measurements are obtained using a CSM (Pham, Michel & Lecoffre 1997; Khoo et al. 2016) at the Australian Maritime College (AMC) cavitation tunnel.…”

A Venturi tube design for studying travelling bubble cavitation

“…Therefore, travelling bubble cavitation is commonly used to reflect the properties of cavitation nuclei group [3,5,6], which is important for cavitation inception properties of fluid [7] and some cavitation types (such as the tip-leakage vortex cavitation [8]) that are particularly concerned in engineering. Pham et al [9] designed a Venturi tube with a center body for dynamical cavitation nuclei measurement by generating travelling bubble cavitation, the acoustic signals generated by travelling bubbles' collapse were collected to count the bubbles, and the content of cavitation nuclei was further calculated. Besides, travelling bubble cavitation can be considered as a series of individual cavitation bubbles moving with fluid, so these travelling bubbles can be utilized to study dynamics and acoustic emission of individual cavitation bubble in the actual flow field, as well as interactions between individual cavitation bubble and the flow field.…”

“…This method can generate cavitation bubbles at particular locations very stably, usually only one bubble can be generated at a time, and it cannot reflect the properties of the cavitation nuclei group. The other is the hydrodynamic method, which is to generate a low-pressure region by a specific flow and further cavitation nuclei can be excited [3,9,5,6]. A large number of travelling cavitation bubbles can be produced at a time by this method and the properties of the cavitation nuclei group can be reflected.…”