Dynamics and preconditioning in a single drop vapor explosion
2007 (English)In: Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12, 2007Conference paper (Refereed)
In order to develop a mechanistic understanding of the thermal-hydraulic processes in vapor explosion, it is paramount to characterize the dynamics of the hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. In the present study, these intricate phenomena are investigated by performing well-controlled, externally triggered, single-drop experiments, employing a high-speed digital visualization system with synchronized cinematography and X-ray radiography system called SHARP (Simultaneous High-speed Acquisition of X-ray Radiography and Photography). The processed images, after an elaborate image processing, revealed the internal structure and dynamic evolution of the hot liquid fragmentation and related vaporization of the coolant. Such data gives way to new insights into the physics of the vapor explosion phenomena and quantification of the associated dynamic micro interactions. Analysis of the experimental results shows that, followed an external perturbation (trigger), a high temperature molten material (tin) drop underwent deformation and partial fragmentation already during the first cycle of bubble growth. Analysis of the SHARP data reveals correlation between the drop's dynamics in the first bubble cycle and energetics of the subsequent explosive evaporation in the second cycle. This finding provides a basis to suggest a so-called melt drop preconditioning i.e. deformation/ pre-fragmentation of a hot melt drop immediately following the pressure trigger, being instrumental to the subsequent coolant entrainment and resulting energetics of the so-triggered drop explosion.
Place, publisher, year, edition, pages
Energetics, Melt dynamics, Pre-conditioning, Simultaneous visualization, Vapor explosion
IdentifiersURN: urn:nbn:se:kth:diva-155293ScopusID: 2-s2.0-44349165747ISBN: 0894480588ISBN: 978-089448058-4OAI: oai:DiVA.org:kth-155293DiVA: diva2:760745
12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12, 30 September 2007 through 4 October 2007, Pittsburgh, PA, United States
QC 201411042014-11-042014-11-042014-11-04Bibliographically approved