A combined cycle power generation system for an aircraft includes fuel cell and supercritical CO.sub.2 cycles. The fuel cell cycle includes a compressor and turbine disposed on a first shaft, a fuel cell in fluid communication with the compressor and a fuel source, and a combustor in fluid communication with the fuel cell and the turbine. The combustor is configured to combust partially spent fuel from the fuel cell and produce combustion exhaust gas for delivery to the turbine. The supercritical CO.sub.2 cycle includes a compressor and turbine disposed on a second shaft, a supercritical CO.sub.2 fluid circuit in thermal communication with the combustor and configured to deliver CO.sub.2 to the turbine and compressor, and a heat exchanger in thermal communication with the supercritical CO.sub.2 fluid circuit and a source of cooling fluid. A mechanical linkage is configured to transfer power from the second shaft to the first shaft.

An energy storage plant includes a casing for the storage of a working fluid other than atmospheric air, in a gaseous phase and in equilibrium of pressure with the atmosphere; a tank for the storage of said working fluid in a liquid or supercritical phase with a temperature close to the critical temperature; wherein said critical temperature is close to the ambient temperature. The plant is configured to carry out a closed thermodynamic cyclic transformation, first in one direction in a charge configuration and then in the opposite direction in a discharge configuration, between said casing and said tank; wherein in the charge configuration the plant stores heat and pressure and in the discharge configuration generates energy.

A vacuum pump includes a linked-type thread-groove spacer which is a structure for linking a Siegbahn pump portion and a thread-groove pump portion, and when an outlet position of a thread groove which is an exhaust channel portion of this linked-type thread-groove spacer is in a vicinity of the stator portion (stator bolt) of the stator column, conductance of the exhaust channel is lowered. Thus, phases in a circumferential direction of installation positions of a thread ridge of the linked-type thread-groove spacer and the stator portion of the stator column are aligned as much as possible. In other words, the thread groove of the linked-type thread-groove spacer which is the exhaust channel is provided between the installation positions of the stator portions in the circumferential direction of the stator column so that lowering of the conductance of the exhaust channel is suppressed.

A geared compressor includes a drive gear, a first intermediate gear, a second intermediate gear, a first impeller and a second impeller connected to a first driven gear, and a third impeller and a fourth impeller connected to a second driven gear. When viewed from an axial direction, a drive axis of the drive gear is disposed below a first intermediate axis of the first intermediate gear, a second intermediate axis of the second intermediate gear, a first driven axis of the first driven gear, and a second driven axis of the second driven gear in a vertical direction. The first impeller has a larger outer diameter than the second impeller, the third impeller, and the fourth impeller.

In a vacuum pump, an outer diameter of a spiral plate disposed on a downstream side is set smaller than an outer diameter of a spiral plate disposed on an upstream side. Specifically, a stepped portion is provided by setting a blade length of the spiral plate disposed on the downstream side shorter than a blade length of the spiral plate disposed on the upstream side. In addition, in a spacer provided in the stepped portion, a relief formation portion is provided to allow a contact surface in contact with an upstream spacer (i.e., spacer opposed to the spiral plate having the unreduced outer diameter) and a contact surface in contact with a downstream spacer (i.e., spacer opposed to the spiral plate having the reduced outer diameter) in the stepped portion to have an equal inner diameter.

A vacuum pump includes a linked-type thread-groove spacer which is a structure for linking a Siegbahn pump portion and a thread-groove pump portion, and when an outlet position of a thread groove which is an exhaust channel portion of this linked-type thread-groove spacer is in a vicinity of the stator portion (stator bolt) of the stator column, conductance of the exhaust channel is lowered. Thus, phases in a circumferential direction of installation positions of a thread ridge of the linked-type thread-groove spacer and the stator portion of the stator column are aligned as much as possible. In other words, the thread groove of the linked-type thread-groove spacer which is the exhaust channel is provided between the installation positions of the stator portions in the circumferential direction of the stator column so that lowering of the conductance of the exhaust channel is suppressed.

A vacuum pump includes: a casing formed with an inlet port or outlet port; a stator disposed inside the casing; and a rotor enclosed in the casing and including a shaft rotatably supported on the stator, and a rotor blade formed in a cylindrical shape with a plurality of blades arranged in multiple stages on an outer circumferential portion thereof, and secured to the shaft such as to be integrally rotatable therewith. The rotor blade is provided with a rupture location control groove as a rupture location control means that locally reduces rigidity of the rotor blade to control a location where the rotor blade ruptures.

An air circulator includes a blower unit that is provided with an airflow opening on its front side, and a support unit that supports the blower unit. A grill is provided in the airflow opening. The grill is provided with plural airflow guide blades in a spiral manner. Inner end portions thereof closer to the center of the spiral of the airflow guide blades are protruded from outer end portions thereof in an airflow direction. The blower unit has a cover for forming an outer panel thereof, and the cover has a spherical shape.

A compressor includes a rotor, a stator, a coil, a shell, an impeller and at least one main gas passage, where the stator and the coil are sleeved on the rotor, the shell covers the stator and the coil, the shell is enclosed at a tail end of the compressor to form a high-pressure chamber, the impeller is sleeved at a tail end of the rotor and faces toward a gas intake direction, the main gas passage surrounds the stator, and an outlet at a tail end of the main gas passage is connected to the high-pressure chamber through the impeller. The compressor can solve the technical problems of complex structure, large size and hard heat dissipation of the existing compressor. A rotor system and a microturbine including the compressor are provided.

A nacelle system having a translating structure is disclosed. In various embodiments, the nacelle system includes a fixed structure; a thrust reverser having a translating sleeve configured to translate relative to the fixed structure and in response to a first dual-circuit hydraulic system; and a variable area fan nozzle having a translating nozzle configured to translate relative to the translating sleeve and in response to a second dual-circuit hydraulic system.