Acoustic noise analysis in multiphase fluid flow patterns within circular pipe

Abstract

This study investigates the numerical exploration of acoustic noise generated by different flow patterns within a horizontal circular pipe, employing validated numerical methods such as large eddy simulation, continuous surface model, and the Ffowcs Williams–Hawkings acoustic model for simulating a complex three-dimensional multiphase fluid flow and acoustic noise. The research mainly focuses on the significant influence of flow patterns on acoustic noise generation through detailed analyses of pressure, velocity, and turbulent kinetic energy across three distinct source regions within the flow. Three flow patterns are examined. The stratified flow is characterized by the complete segregation of the two phases. The plug flow is defined by large, elongated bubbles typically moving in the axial direction with a periodic nature. The slug flow is characterized by the rapid formation of large, elongated gas bubbles separated by liquid phases. In the stratified flow, noise generation primarily stems from pressure fluctuations near phase interfaces. Plug flow exhibits noise due to bubble–surface interactions, particularly near the outlet. Slug flow generates noise from interactions between liquid waves and the pipe surface. Comparing sound pressure levels across flow patterns reveals higher noise levels in the plug and slug flows compared to the stratified flow, attributed to their disruptive nature. Total sound pressure level analysis indicates slug flow as the highest noise producer, highlighting phenomena such as interface breaking. The present study will contribute to effective mitigation strategies in engineering applications by providing an understanding of flow dynamics and noise generation mechanisms.