Validation of X-ray radiography for characterization of gas bubbles in liquid metals

Abstract

Optimization of exposure factors for X-ray radiography non-destructive testing of pearl oyster Susilo, I Yulianti, A Addawiyah et al.-A Thermoluminescent Radiography Akira Doi, Takashi Kanie and Akira Naruse -Development of 4.5 keV monochromatic X-ray radiography using the high-energy, picosecond LFEX laser H Sawada, S Fujioka, T Hosoda et al. Abstract. X-ray radiography has proved to be an efficient and powerful tool for the visualization of two-phase flows in non-transparent fluids, in particular in liquid metals. This paper presents a validation of the X-ray radiography by comparing measurements in water with corresponding results obtained by optical methods. For that purpose Ar bubbles were injected through a single orifice. The measurements results are compared in terms of bubble size, bubble shape and velocity. Furthermore, visualization experiments were performed in the eutectic alloy GaInSn where the image contrast between the liquid phase and the gas bubble is much stronger. Some obvious differences of the bubble dynamics in water and GaInSn are discussed.

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].…”

CFD Modeling and Experimental Validation of Top-Submerged-Lance Gas Injection in Liquid Metal

“…Images with a good intensity contrast and low signal-to-noise ratio can only be achieved by using a flat geometry of this kind. Previous measurements [18,21,22] have shown that a gap of D ¼ 12 mm is a good compromise. On one hand, the image contrast obtained in this configuration is sufficient to clearly visualize bubbles and gas-liquid interfaces; on the other hand, the moderate geometric restriction still allows for the development of sufficient dynamics of both the bubble plume and the free surface of the melt.…”

“…The applicability of X-ray radiography for quantitative measurement of bubbles rising in a stagnant liquid was already validated in previous studies. [21] In all the experiments presented here, the size of the observation window was approximately 106 Â 156 mm 2 (1730 Â 2560 px 2 ), yielding a spatial resolution of each pixel of l px ¼ 0:061 mm: The difference between the very high attenuation of X-ray radiation of the liquid metal and the extremely weak attenuation of Ar leads to a clear contrast in the resulting images. The local image intensity correlates with the fraction of gas at a specific position in the yÀz plane.…”

“…The experiments were carried out in the X-ray laboratory at HZDR. The experimental configuration is almost identical to the measuring arrangement developed by Keplinger et al [21,22] to investigate the behavior of bubble plumes generated by bottom gas injection. The ternary alloy GaInSn at the eutectic composition was used as a model fluid which is liquid at room temperature.…”

“…[16] This measurement technique has been successfully applied to investigate liquid metal multiphase flows. [17][18][19][20][21][22] The experimental activity of Akashi et al reveals the complexity of the multiphase flow of TSL Ar injection in the eutectic metal alloy GaInSn. The post-processing applied to the X-ray images allows the flow regime to be characterized and provides the properties of individual bubbles such as size, shape, and trajectory.…”