2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Andrew Cornett, National Research Council, Canada (Presenter)
Frazil ice is a type of ice that forms in fast-flowing supercooled water, consisting of small ice crystals in suspension in the water column which are notorious for adhering to all submerged objects they come in contact with. Frazil is infamously known for blocking water intakes in rivers and estuaries, as crystals stick and build up on the intakes’ trash racks. Such blockages negatively impact water supply facilities, hydropower plants, nuclear power facilities, and vessels navigating in cold waters, and can lead to dramatic impacts, such as a town being left with insufficient water reserves for fire protection, a nuclear facility not getting the cold water required for cooling, or a vessel being forced to shut down its engines and drift.
Our theoretical knowledge of frazil ice is currently quite limited, in part because field and laboratory data on frazil ice is difficult to obtain and hence relatively scarce. New experimental research and field data is needed to gain a much improved understanding of frazil growth and its interaction with structures. Hopefully, such new understanding will eventually lead to theoretical and numerical models that can reliably predict frazil growth and its impacts. While several small-scale laboratory studies have been reported in the literature (in small tanks of ~1 m3, e.g. Clark and Doering, 2006), very few studies document the successfull generation of frazil ice on a larger scale (> ~2 m3, e.g. Ettema et al., 2003; Smedsrud, 2001).
This paper will describe the development and operation of a new frazil ice research facility at the National Research Council of Canada where frazil can be reliably generated and its interaction with objects studied under controlled repeatable conditions. The new facility features a water volume of 120 m3 and turbulent flow speeds up to 1 m/s. The use of this new facility to investigate the effects of frazil on the blades of a hydrokinetic turbine will also be described.
Clark, S. and J.C. Doering 2006. Laboratory Experiments on Frazil-Size Characteristics in a Counterrotating Flume. Journal of hydraulic engineering (ASCE), 132(1): 94-101.
Ettema, R., Chen, Z. and J. Doering, 2003. Making frazil ice in a large ice tank. Proceedings of the 12th CRIPE conference, Edmonton, AB, June 19-20, 2003.
Smedsrud, L.H., 2001. Frazil-ice entrainment of sediment: large-tank laboratory experiments. Journal of Glaciology, 47(158): 461-471.