Continuous siphon vacuum pump driven by tidal energy(TEVP)

with its experimentally-proved suction capacity over 2?10-5 kg gas?(kg sea water)-1 employing 3.5 m tidal height margin under 7.5 kPa(abs.)suction pressure

showed the potential of industrial application based on reliable theoretical principles.Sea water could be used as working fluid for vacuum suction prior to performing as cooling medium for a coastal plant.In a 900 MW pressurized water reactor nuclear power station

a 132 kW mechanical vacuum pump with 61.4 kg穐-1 of suction capacity under the pressure of 7.5 kPa(abs.)was expected to be replaced by a TEVP employing sea water with a flow rate of 3070 t穐-1.The suction capacity would be increased along with the increase of suction pressure

which was constrained by the rate of momentum transfer between gas and liquid phases

or the maximum of momentum flow rate of the gas phase.In order to avoid siphon break-off

the velocity of sea water in the siphon pipe should be greater than the velocity under the maximum momentum flow rate of the gas phase.The ideal suction efficiency could reach 0.6 when involving a smooth pipe model for calculation and ignoring local flow resistance

but it would sharply decrease taking into consideration the local flow resistance loss caused by valves and other pipe fittings.Therefore it was a basic principle to avoid flow resistance caused by pipe fittings regarding the gas/liquid two-phase flow for a TEVP to ensure its performance in high efficiency region.