Open cycle-ocean thermal energy conversion: Experimental study of flash evaporation

France´s Ocean Thermal Energy Conversion program has shown the feasibility and competitiveness of open or closed cycle systems for plants generating less than 20 MWe. The design of a 5 MWe shore-based pilot plant for Tahiti began in 1982. The second stage of the program now in progress will select the most effective cycle for the Tahiti plant. This paper presents initial experiments with the vertical-spout flash evaporator designed for the open cycle version. Results cover variable water flows in terms of the non-equilibrium pressure differences at the inlet and outlet, gas release, liquid entrainment and liquid-side pressure drop. Three modes of evaporation dictated by bubble bursting conditions are described and the effects of salinity, jet interaction and spout height are discussed.