A startup method of a Francis turbine according to an embodiment includes: a first rotation-speed increasing step in which a rotation speed of the runner is increased by opening the guide vane at a first opening; a second rotation-speed increasing step in which the increase in the rotation speed of the runner is accelerated by opening the guide vane at a second opening that is larger than the first opening after the first rotation-speed increasing step; and a rotation-speed regulating step in which the rotation speed of the runner is regulated to a rated rotation speed by opening the guide vane at a no-load opening after the second rotation-speed increasing step. The first opening is an opening that is half or less than the no-load opening.

A startup method of a Francis turbine according to an embodiment includes: a bypass-valve opening step of opening the bypass valve with the inlet valve closed; an inlet-valve opening step of opening the inlet valve after the bypass-valve opening step; and a first rotation-speed increasing step of increasing a rotation speed of the runner by opening the guide vane at an opening that is 50% or more of a maximum opening before a flow velocity of a swirling flow flowing around the runner reaches 90 m/sec.

This disclosure includes subsea pumping apparatuses and related methods. Some apparatuses include one or more subsea pumps, each having an inlet and an outlet, and one or more motors, each configured to actuate at least one pump to communicate a hydraulic fluid from the inlet to the outlet, where the subsea pumping apparatus is configured to be in fluid communication with a hydraulically actuated device of a blowout preventer. Some subsea pumping apparatuses include one or more of: a desalination system configured to produce at least a portion of the hydraulic fluid; one or more valves, each configured to selectively route hydraulic fluid from an outlet of a pump to, for example, a subsea environment, a reservoir, and/or the inlet of the pump; and a reservoir configured to store at least a portion of the hydraulic fluid. Some apparatuses are configured to be directly coupled to the hydraulically actuated device.

A compression pipe is configured with a wave drawing section and an air compressing section, a gas-liquid introduction on-off valve is disposed in wave drawing section, a gas-liquid introduction on-off valve is opened at an initial stage of a pushing wave, the gas-liquid introduction on-off valve is closed at the same time when a wave that maintains a speed flows into a wave receiving box. Accordingly, the wave is drawn into the air compressing section, is stored in a compressed air storage tank by converting kinetic energy of the wave into compressed air, and can be utilized for power generation and the like.

Apparatus for extracting energy from an oscillating working fluid, the apparatus comprising a flow passage 40 for the oscillating working fluid, an energy conversion unit 44 and a flow control device 38, each of the energy conversion unit 44 and the flow control device 38 being, at least in part, in fluid communication with the flow passage 40, wherein in use the flow control device 38 is selectively operable between a first configuration in which the flow control device 38 is open to allow a flow of the oscillating working fluid to exit the flow passage therethrough, and a second configuration in which the flow control device 38 is arranged to restrict a flow of the working fluid therethrough, such that the oscillating working fluid enters the flow passage via the energy conversion unit 44.

A valve system for controlling the fluid flow in a duct, includes: a valve body adapted to be inserted in an interruption of the duct, and provided with an inlet and an outlet for a flow of fluid in the duct, a lateral flow valve, developing substantially transversally in the duct, placed in the valve body upstream of the fluid flow, the valve having an obstructer capable of moving transversally in the duct to “laterally” interrupt part of the fluid flow in the duct, an actuator adapted to move the obstructer from a first position, in which the duct is fully open, to a second position, in which the duct is fully closed, a rotor shaped substantially as a turbine, placed inside the valve body downstream of the valve with respect to the fluid flow, the rotor being located at a distance from the valve comprised within a pressure recovery zone, the pressure being generated by the valve in the absence of the turbine.

A floating oscillating water column-type wave energy power generation apparatus includes a first runner chamber and a protective cap, wherein a nozzle is mounted inside the first runner chamber, a flow-guiding cone is coaxially mounted below the nozzle, the flow-guiding cone is conical and arranged with a tip facing down; an impeller is coaxially mounted above the nozzle; a power generator is coaxially mounted above the impeller; the protective cap is mounted at the top of the first runner chamber; and a gap is provided between an edge of the protective cap and an edge of the first runner chamber for air circulation. According to the floating oscillating water column-type wave energy power generation apparatus, as the nozzle with the flow-guiding cone structure is used, the flow-guiding cone can guide air flowing, and increase the air flowing speed in the apparatus.

A compression pipe is configured with a wave drawing section and an air compressing section, a gas-liquid introduction on-off valve is disposed in wave drawing section, a gas-liquid introduction on-off valve is opened at an initial stage of a pushing wave, the gas-liquid introduction on-off valve is closed at the same time when a wave that maintains a speed flows into a wave receiving box. Accordingly, the wave is drawn into the air compressing section, is stored in a compressed air storage tank by converting kinetic energy of the wave into compressed air, and can be utilized for power generation and the like.

A hybrid heat engine system includes a valve configured to provide first fluid from a heat source. The hybrid heat engine system further includes one or more first pipes fluidly coupled between the valve and a turbine. The one or more first pipes house a second fluid. The hybrid heat engine system further includes a chamber disposed between the valve and the one or more first pipes. The hybrid heat engine system further includes a piston disposed in the chamber between the first fluid and the second fluid. At least a portion of the second fluid is to be pushed through the turbine to generate energy responsive to actuation of the valve.

A tidal power generation device includes a container assembly and a power generation device arranged in the container assembly. A water inlet of the container assembly allows a tidal water flow to enter. An entrance guide plate of the container assembly causes the water flow to advance in the direction of the power generation device to push the power generation device's thrust plates, and thereby driving the power generation device's thrust plate traction mechanism to make a power generator of the power generation device convert kinetic energy into electrical energy. After the water flow pushes the thrust plates, it enters a pressure accumulating pool of the container assembly. Then, the water flow in the pressure accumulating pool flows to a backflow guide plate of the container assembly, and flows to a first pressure relief pool of the container assembly to continue pushing the thrust plates.