Flow and heat transfer simulations for the design of the Helsinki Vuosaari harbour ice control system

Abstract

The accelerated growth of brash ice is a problem that the port operator has to deal with in busy cold region harbour basins. Flow and heat transfer simulations have to be used to investigate the ice control design options for the new Helsinki Vuosaari harbour. For that purpose, a flow and heat transfer solver has been modified to combine 3 types of empirical ice-melting models, i.e. the smooth ice model, the slightly rough ice model and the rough ice model, as the heat transfer boundary conditions. A simple bubbler model has also been developed into the flow solver to simulate the complicated bubble-driven water flow in the harbour basin. The ice control problem for the Vuosaari harbour has two parts. One is the supply of warm water across a narrow basin. A suction pump arrangement has been studied as an alternative to crossing the basin with a pipe. The thermal energy balance and the ice melting in the basin have been estimated numerically. The numerical investigations show that the heat-supply efficiency can be of the order of 95% if the suction is 5 m 3 /s while the warm water supply flow is 4 m 3 /s. The principal problem is how to combine the warm water supply and bubbler devices to melt ice effectively in the main harbour basin. Five design options with different warm water supply locations and bubbler arrangements have been studied using numerical simulations. A solution that provides fairly even ice-melting patterns for the berths has been found. More than 70% of the thermal input gets used for ice melting in the basin according to the simulation. The paper illustrates, how flow and heat transfer simulations can be used for the design of ice control systems. It shows that the use of bubbler lines may greatly improve the efficiency of warm water input in ice control.