Visualization of the global flow structure in a modified Rayleigh-Bénard setup using contactless inductive flow tomography. (August 2018)

• Record Type: Journal Article
• Authors: Wondrak, Thomas; Pal, Josef; Stefani, Frank; Galindo, Vladimir; Eckert, Sven
• Is Part Of: Flow measurement and instrumentation. Volume 62(2018)
• Page Start: 269
• Page End: 280
• Publication Date: 2018-08
• Subjects: Rayleigh-Bénard convection -- Contactless inductive flow tomography; Fluid dynamic measurements -- Periodicals; Flow meters -- Periodicals; Fluides, Dynamique des -- Mesure -- Périodiques; Débitmètres -- Périodiques; 681.2805
• DOI: 10.1016/j.flowmeasinst.2017.08.001
• Languages: English
• ISSNs: 0955-5986

Abstract

Abstract: Rayleigh-Bénard convection is not only a classical problem in fluid dynamics but plays also an important role in many metallurgical and crystal growth applications. The measurement of the flow field and of the dynamics of the emerging large-scale circulation in liquid metals is a challenging task due to the opaqueness and the high temperature of the melts. Contactless inductive flow tomography is a technique to visualize the mean three-dimensional flow structure in liquid metals by measuring the flow induced magnetic field perturbations under the influence of one or several applied magnetic fields. In this paper, we present the first measurements of the flow induced magnetic field in a Rayleigh-Bénard setup, which are also used to investigate the dynamics of the large-scale circulation. Additionally, we investigate numerically the quality of the reconstruction of the three-dimensional flow field for different sensor configurations. Highlights: Contactless inductive flow tomography (CIFT) is applied for the first time to visualize Rayleigh-Bénard (RB) convection. CIFT allows the investigation of the large scale circulation (LSC) in an RB cell without any contact with the melt. For five temperature differences the measured magnetic field perturbations have unveiled a variety of flow phenomena. For a small temperature difference of 2.2 K the LSC is pinned at some angle from were it undergoes slight oscillations. For higher temperature differences reversals of the LSC and one cessation were observed.