A ventilation unit (1) is formed by at least one fan (2), a heat exchanger, axially spaced from the fan (2), and a housing (3). The housing (3) has a first housing section (4), with a constant flow cross-section, where the heat exchanger is arranged. A second housing section (5) adjoins the first section (4) in the axial flow direction. The fan (2) is arranged on the second housing section (5) in the axial flow direction. During operation, the fan conveys air through the heat exchanger, arranged in the first housing section (4), and through the second housing section (5). The flow cross-section of the second housing section (5) is reduced in the flow direction from the first housing section (4) to the fan (2) by an adaptation to the form of housing wall sections (6, 6′) of the second housing section (5).

The present disclosure is directed to an aircraft power generation system including a reverse Brayton cycle system, a gas turbine engine, and a gearbox. The gas turbine engine includes a compressor section, a turbine section, and an engine shaft. The compressor section is arranged in serial flow arrangement with the turbine section. The engine shaft is rotatable with at least a portion of the compressor section and with at least a portion of the turbine section. The reverse Brayton cycle system includes a compressor, a driveshaft, a turbine, and a first heat exchanger. The driveshaft is rotatable with the compressor or the turbine, and the compressor, the first heat exchanger, and the turbine are in serial flow arrangement. The gearbox is configured to receive mechanical energy from the engine shaft and transmit mechanical energy to the reverse Brayton cycle system through the driveshaft.

A centrifugal compressor includes a rotation shaft, a compressor impeller attached to one end of the rotation shaft, and a first wall surface and a second wall surface formed inside a housing so as to face each other in an axial direction. A diffuser is formed between the first wall surface and the second wall surface in the axial direction, and a wall portion separates the diffuser from an axial space inside the housing in which the rotation shaft extends. The wall portion includes at least one extraction hole that fluidly couples the diffuser to the axial spate and that is configured to extract a gas from the diffuser.

A gas compressor system is provided to operate at a well site and to inject a compressible fluid into a wellbore in support of a gas-lift operation. Methods and systems are provided that allow for the automated individual control of discharge temperatures from coolers for gas injection, in real time, wherein the temperature control points of the first and/or second stage cooler discharges are automatically controlled by a process controller in order to push heat produced by adiabatic compression to a third or final compression stage. In this way, discharge temperatures at the final stage are elevated to maintain injection gaseous mixtures in vapor phase.

A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream most end, and more upstream locations. A turbine section has a high pressure turbine. A first tap taps air from at least one of the more upstream locations in the main compressor section, passes the tapped air through a heat exchanger and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger. A second tap taps air from a location closer to the downstream most end than the location(s) of the first tap. The first and second tap mix together and are delivered into the high pressure turbine. An intercooling system for a gas turbine engine is also disclosed.

A gaseous compression system for compressing a gas from an initial pressure to an exit pressure with a first, blower compression bank and a second, mechanical compression bank. Each compression bank has plural stages of gaseous compression with a gaseous fluid compressor and a heat pump intercooler. The heat pump intercooler comprises a cascading heat pump intercooler with a high temperature section, a medium temperature section, and a low temperature section, each temperature section with an intercooler core. Each stage of the blower compression bank has a high-pressure blower, and each stage of the mechanical compressor bank has a mechanical compressor. A final stage of gaseous compression is without a heat pump intercooler. Gas compressed by the gaseous fluid compression system can be injected into a gas-driven generator to generate electric power from movement of a working fluid induced by injection of the compressed gas.

An apparatus and method for cooling a gas stream is provided comprising at least one heat exchanger in which a gas stream is cooled against a cooling liquid, whereby the cooling liquid temperature increases from a first temperature to a second temperature, at least one air cooler for cooling the cooling liquid after passing though the at least one heat exchanger, surface area of the at least one air cooler being designed to decrease temperature of the cooling liquid to the first temperature; a pump; and conduits to form a closed-circuit for the cooling liquid to pass continuously through the at least one heat exchanger and the at least one air cooler. The ratio of surface area of the at least one air cooler to the surface area of the at least one heat exchanger is optionally 12 or lower, and the difference of temperature between the second temperature and first temperature being greater than 15° C.

A multi-stage electric centrifugal compressor configured to drive impellers disposed at both ends of a rotational shaft by an electric motor includes: the rotational shaft; a low-pressure-stage impeller disposed at one end of the rotational shaft; a high-pressure-stage impeller disposed at the other end of the rotational shaft; a high-pressure-stage housing accommodating the high-pressure-stage impeller; and a connecting pipe for supplying a compressed gas compressed by the low-pressure-stage impeller to the high-pressure-stage housing. The high-pressure-stage housing has a high-pressure-stage inlet opening that opens in a direction intersecting an axis of the rotational shaft. The connecting pipe includes a high-pressure-stage-side connection portion connected to the high-pressure-stage inlet opening.

In a turbofan, a first curve, formed by projecting a leading edge onto a plane perpendicular to a rotating shaft, has a first inflection point and has a portion that is convex at a point closer to the first inflection point than the first point is in a counter-rotational direction and a portion that is convex at a point closer to the second point than the first inflection point is in the rotational direction, the first point is located forward of the second point in the rotational direction, a second curve, formed by projecting the trailing edge onto a plane perpendicular to the rotating shaft, follows an arc centered on the rotating shaft in a top view, a third curve, formed by projecting the trailing edge onto a cylindrical plane coaxial with the rotating shaft, is formed so as to be convex in the rotational direction, and a junction point of the third curve and the shroud is located behind the junction point of the third curve and the main plate in the rotational direction.

A process for producing compressed hydrogen gas including: electrolysing water to produce hydrogen gas, and compressing the hydrogen gas in a multistage compression system including: a centrifugal compression stage and a recycle system for recycling a portion of the hydrogen gas from a product end to a feed end of the centrifugal compression stage; wherein hydrogen gas feed is fed to the feed end at a pre-determined feed temperature and pressure and mole fraction of water; wherein a portion of the hydrogen gas is removed from the product end, reduced in pressure in the recycle system to the pre-determined feed pressure and is then recycled to form at least part of the hydrogen gas feed to the centrifugal compression stage; and further including cooling hydrogen gas comprising the reduced pressure hydrogen gas such that the water mole fraction in the hydrogen gas feed is at the pre-determined water mole fraction.