Combined experimental and numerical analysis of a bubbly liquid metal flow

Abstract

Abstract. The paper proposes a combined experimental and numerical procedure for the investigation of bubbly liquid-metal flows. It describes the application to a model configuration consisting of a recirculating GaInSn flow driven by an argon bubble chain. The experimental methods involve X-ray measurements to detect the bubbles and UDV measurements to gain velocity information about the liquid metal. The chosen numerical method is an immersed boundary method extended to deformable bubbles. The model configuration includes typical phenomena occurring in industrial applications and allows insight into the physics of bubbly liquid-metal flows. It constitutes an attractive test case for assessing further experimental and numerical methods.

Phase boundary dynamics of bubble flow in a thick liquid metal layer under an applied magnetic field

“…XR and XCT methods allow for direct observation of bubble shapes. However, x-ray based techniques are, in general, very constrained by relatively small liquid metal thickness in the beam direction due to intense x-ray attenuation by liquid metals [20][21][22][23][24]. XCT, while offering very high temporal resolution and sufficient phase boundary detection precision, also entails experimental systems that are rather susceptible to applied MF, rendering them hardly applicable to studies of magnetohydrodynamic (MHD) bubble flow [25][26][27].…”

Resolving Gas Bubbles Ascending in Liquid Metal from Low-SNR Neutron Radiography Images

“…Through recent efforts and the advent of dynamic X-ray and neutron radiography of two-phase liquid metal flow [36][37][38][39][40][41][42], fundamental investigation of bubble chain systems mimicking industrially relevant flow conditions is underway [1,8,15,28,29,36,[43][44][45][46]. In bubble chain flow, bubbles are released into a liquid metal system one-by-one with a uniform time delay between each, at a certain gas flow rate, and ascend to the free surface of liquid metal.…”

“…Bubble chains are still simple enough to enable experimentation with compact systems [1,8,43,45,46] and contain computationally manageable numbers of bubbles within the liquid metal volume [8,15,43,45]. Meanwhile, they already exhibit collective dynamics between leading and trailing bubbles [8,15,[43][44][45] and, depending on the system geometry and flow rate, bubble agglomeration, coalescence and breakup can occur [28,29,36].…”

“…However, despite the relative simplicity, dynamics exhibited by bubble chain flow in liquid metal without or with applied MF are still very complex. Depending on the gas flow rate, bubbles produce unstable elongated wake flow regions where periodic vortex detachment occurs and turbulent pulsations are generated-shed vortices and turbulent wakes of leading bubbles strongly affect the trailing bubbles, leading to bubble pair coupling across the ascending chain [8,15,43,45,[51][52][53][54]. There exists a feedback loop involving combined perturbations of bubble shapes and within the bubble chain, surrounding liquid metal flow, and the influence of the free surface at the top of the metal vessels with instabilities and oscillations in the bubble chain shape [8,15,43,45,54].…”

“…Depending on the gas flow rate, bubbles produce unstable elongated wake flow regions where periodic vortex detachment occurs and turbulent pulsations are generated-shed vortices and turbulent wakes of leading bubbles strongly affect the trailing bubbles, leading to bubble pair coupling across the ascending chain [8,15,43,45,[51][52][53][54]. There exists a feedback loop involving combined perturbations of bubble shapes and within the bubble chain, surrounding liquid metal flow, and the influence of the free surface at the top of the metal vessels with instabilities and oscillations in the bubble chain shape [8,15,43,45,54]. Recently, dynamic mode decomposition (DMD) has been applied to the output of the MHD bubble chain flow simulation to study both large-scale flow structures and bubble wake flow in the bubble reference frame [55].…”