<p>Arctic oil spills are particularly detrimental as they could potentially cause extensive ice melting in addition to the overall environmental pollutions they create. A large-scale spill in the Arctic waters, similar to the Deepwater Horizon spill in 2012, could trigger ice sheet deterioration and negatively impact climate cycles globally. Floating oil slicks amongst ice floes absorb ambient energy, i.e., sunlight or energy sources created by cleanup operations such as in situ burning, and transfer that energy to the ice to aggravate melting in thaw season. However, no studies have been undertaken to reveal how oil-ice interaction impacts ice melting. In particular, melting caused by an adjacent immiscible liquid layer and heat transfer to ice in such a condition is not well understood, and basic temperature and velocity field measurements are required to understand the heat transfer mechanisms. This research employs a newly developed simultaneous temperature and velocity field measurement technique to investigate the heat transfer pathways from an oil slick to ice. Temperature measurements are performed by developing a dual-luminescent imaging technique. Two luminescent probes in dual-luminescent imaging have different luminescent characteristics: one probe outputs the temperature-dependent luminescent intensity, another probe outputs the temperature-independent luminescent intensity. Luminescent peaks of the two probes should lie at different wavelengths so that each luminescent output can be acquired by different color images of a high-speed color camera. By taking a ratio of the different color images, spatiotemporal temperature information of oil will be extracted. One challenge in terms of the measurement technique is the dynamic motion of ice as it is melting. The ice-melting moves the geometric position of the ice, especially the interface between the ice-oil. Because of this dynamic motion, dual-luminescent imaging, which is able to capture temperature information over moving objects, is chosen as a unique diagnostic tool. Determining luminescent probes to extract the spatiotemporal temperature of the oil is one of the essential requirements to establish this imaging system. Toluene is selected to represent the spilled fuel, which is immiscible in water as most hydrocarbon petroleum fuels are. The europium-based and pyrene-based luminophore is dissolved into Toluene to result in to be dual-luminescent oil. Seeding particles were also added to Toluene to capture the velocity field of the liquid-phase using particle tracking velocimetry (PTV) technique. A combination of the two techniques for Toluene in a side cooled cavity is performed to capture temperature and velocity field information, respectively. The side cooled cavity simply imitates the ice-oil interface except for the ice melting, which later will be added to future experiments. In the cavity, temperature differences between the cooled side and the oil drive a flow, making a velocity field. Consecutive images were acquired consecutively to obtain temporal information over the side cooled cavity. Seeding particles for PTV were mixed into the fuel, and the particles' consecutive imaging provided the spatiotemporal velocity field of the fuel in the cavity. The results show that the convective field is directly coupled with the temperature field, i.e., the temperature difference instigates a flow in the liquid. Successful implementation of the two measuring techniques together is a step toward analyzing heat transfer pathways in a liquid fuel adjacent to an ice body, indicating the melting extent.</p>

Dual-Luminescence Imaging and Particle Tracking Velocimetry for Simultaneous Temperature and Velocity Field Measurements in Hydrocarbons Liquid

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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