Abstract: A heat exchange system includes: a gas line through which a gas to be cooled flows; a first heat exchanger disposed in the gas line and configured to cool the gas through heat exchange with a refrigerant; a refrigerant introduction line for introducing the refrigerant into the first heat exchanger; a refrigerant discharge line for discharging the refrigerant after cooling the gas from the first heat exchanger; a recirculation line for recirculating at least a part of the refrigerant flowing through the refrigerant discharge line into the refrigerant introduction line; and a flow-rate adjustment unit for adjusting a flow rate of the refrigerant flowing through the recirculation line so that a temperature of the refrigerant introduced into the first heat exchanger from the refrigerant introduction line is not lower than a threshold.

Abstract: A centrifugal compressor includes a motor that rotates a rotary shaft of a compressor impeller, a motor housing that houses the motor, a compressor housing that houses the compressor impeller and includes an intake port and a discharge port, an gas bleed port that is provided closer to the discharge port than the compressor impeller in a flow direction in the compressor housing, a cooling gas line which is connected to the gas bleed port and through which a part of compressed gas compressed by the compressor impeller passes, a cooling liquid line of which at least a part is provided in the motor housing and through which cooling liquid of which the temperature is lower than the temperature of the compressed gas passes, and a heat exchanger that is disposed on the cooling gas line and the cooling liquid line.

Abstract: A method for forming a composite part of a gas turbine engine. The method includes assembling the composite part of a first composite material and a second composite material. The second composite material defines an outer surface of the composite part, and is selected to be curable at a cure temperature generated by heat from operation of the engine. The first composite material is selected to have an operating temperature limit less than the cure temperature. The method includes placing the composite part within the engine so that, in use, the second composite material is cured by exposure to the heat generated from operation of the engine. The second composite material thermally shields the first composite material from the heat generated from operation of the engine. The method includes operating the engine to cure the second composite material.

Abstract: A pump for a fuel system include a housing, a pumping element, and a takeoff. The housing has an inlet, an outlet, and channel connecting the inlet to the outlet. The pumping element is supported within the housing and bounds the channel. The takeoff is connected to the housing and is in fluid communication with the channel at a location downstream of the inlet, and upstream of the outlet, to divert partially pressurized fuel for cooling an electronic device. Fuel systems and methods of cooling electronic devices are also described.

Abstract: A modular gas turbine system is disclosed. The system includes a base plate and a gas turbine engine mounted on the base plate. The gas turbine engine has a rotation axis, a first air compressor section and a second air compressor section. A rotating load is mechanically coupled to the gas turbine engine and mounted on the base plate. A supporting frame extends above the base plate and supports a plurality of secondary coolers, which are fluid exchange relationship with an intercooler of the gas turbine engine.

Abstract: Methods and systems are provided for compound boosted engine comprising an electric supercharger. In one example, the electric supercharger may be double-ended with a compressor arranged on either side of an electric motor and rotationally coupled to the electric motor via shafts. The electric supercharger may be configured to provide boost assist to a twin turbocharger system via a bypass channel adapted with a bypass valve.

Abstract: In a two-stage supercharging electric-assist turbocharger, a first compressor wheel, a rotor of an electric motor, a second compressor wheel, and a turbine wheel are coaxially coupled to a same, common shaft member, in that order. A compressor housing is structured to define therein a communicating passage to accommodate the electric motor in the communicating passage. A first water jacket is formed in at least one rib integrally formed with an outer periphery of a motor housing and also serving as a radiating fin, for forced-cooling air flowing through the communicating passage. A second water jacket is formed in a motor housing for forced-cooling a stator of the electric motor. A third water jacket is formed in an intermediate housing constructing a part of the compressor housing for forced-cooling a control unit configured to control the electric motor.

Abstract: An accumulator system is coupled to gas turbines for storing thermal energy in a heat accumulator, having a charge circuit and a discharge circuit. The charge circuit has an electrically operated heat generation device which is configured for generating heat with the utilization of electrical energy. The charge circuit is configured for transferring the heat at least temporarily to the heat accumulator, in order to store the heat therein. The discharge circuit is configured to thermally condition a fluid by the heat from the heat accumulator, and to then guide the fluid to the intake side of a compressor of a gas turbine, wherein the charge circuit has a heat pump as heat generation device.

Abstract: An actuator includes at least one stage of turbo compressor, with an outlet for conveying gas compressed in the at least one stage of turbo compressor to at least one cooler, and a shaft for rotating the at least one stage of turbo compressor, for increasing the pressure of the gas to be supplied to the actuator. The actuator also includes a turbine and a control valve by means of which the flow of compressed gas produced by the turbo compressor to the turbine is arranged to be adjusted. A method for controlling the actuator, as well as a control system for the actuator are also described.

Abstract: A gas turbine engine includes a fan nacelle and a core nacelle spaced radially inwardly of the fan nacelle to define a bypass flowpath. The engine includes a scoop to direct air from the bypass flowpath into an engine core. The scoop is comprised of a first piece extending outwardly of an outer surface the core nacelle to define an air inlet and a second piece extending inwardly of the core nacelle to define an air outlet.

Abstract: A gas turbine engine includes a bearing structure mounted to the front center body case structure to rotationally support a shaft driven by a geared architecture. A bearing compartment passage structure is in communication with the bearing structure through a front center body case structure.

Abstract: A system, including a superconductive heat transfer assembly, including, a first superconductive heat transfer pipe, a second superconductive heat transfer pipe, and a superconductive heat transfer contact switch configured to open and close a gap between the first superconductive heat transfer pipe and the second superconductive heat transfer pipe.

Abstract: An expander-generator is disclosed having an expansion device and a generator disposed within a hermetically-sealed housing. The expansion device may be overhung and supported on or otherwise rotate a hollow expansion rotor having a thrust balance seal being arranged at least partially within a chamber defined in the expansion rotor. Partially-expanded working fluid is extracted from an intermediate expansion stage and a first portion of the extracted working fluid is used cool the generator and accompanying radial bearings. A second portion of the extracted working fluid may be introduced into the chamber defined within the expander rotor via a conduit defined in the thrust balance seal chamber. The second portion of extracted working fluid minimizes unequal axial thrust loads on the expander rotor due to the overhung arrangement.

Abstract: An internally-cooled centrifugal compressor having a shaped casing and a diaphragm disposed within the shaped casing having a gas side and a coolant side so that heat from a gas flowing though the gas side is extracted via the coolant side. An impeller disposed within the diaphragm has a stage inlet on one side and a stage outlet for delivering a pressurized gas to a downstream connection. The coolant side of the diaphragm includes at least one passageway for directing a coolant in a substantially counter-flow direction from the flow of gas through the gas side.

Abstract: A turbocompressor provided with a case, a centrifugal first stage and second stage compressing unit disposed on the case, and a driver unit for driving the first stage and second stage compressing units. The interior of the case is partitioned into a first cooling area which houses a first cooling device, a second cooling area which houses a second cooling device, an oil tank, and a blowoff silencer chamber. The blowoff silencer chamber is located between the oil tank and the first cooling area and the second cooling area in the interior of the case.

Abstract: According to an aspect of an exemplary embodiment, there is provided a compressing system including: a casing including an inlet and an outlet; a first compression unit configured to receive an inlet fluid from the inlet and compressing the inlet fluid into a first pressure fluid; a first pressure chamber configured to receive the first pressure fluid; at least one first intercooler unit configured to cool the first pressure fluid; a second compression unit configured to compress the first pressure fluid into a second pressure fluid; a second pressure chamber configured to receive the second pressure fluid; at least one second intercooler unit configured to cool the second pressure fluid; and a third compression unit configured to compress the second pressure fluid.

Abstract: Methods and systems for controlling a gas turbine system are provided herein. In one embodiment, a method includes the steps of receiving at least one parameter of turbine inlet air and determining, based on the at least one parameter, an expected condensation level at an intercooler disposed downstream of an inlet air chilling system and in-line between a low pressure compressor and a high pressure compressor. The method further includes determining a desired temperature of the turbine inlet air corresponding to substantially no expected condensation at the intercooler and controlling the inlet air chilling system to chill the turbine inlet air to the desired temperature.

Abstract: An example turbomachine cooling arrangement includes a pump configured to pressurize a first turbomachine fluid that is then communicated through a heat exchanger assembly to remove thermal energy from a second turbomachine fluid. A portion of the pump is configured to be housed within a gearbox housing of a turbomachine.

Abstract: In one exemplary embodiment, a gas turbine engine includes a turbine and a high pressure compressor. The high pressure compressor includes a last stage having a last stage compressor blade and a last stage vane. The gas turbine engine includes a first flow path through which bleed air flows to the turbine and a second flow path through which air from the last stage of the high pressure compressor flows. The bleed air in the first flow path exchanges heat with a portion of the air in the second flow path in a heat exchanger to cool the air in the second flow path. The cooled air in the second flow path is returned to the high pressure compressor to cool the high pressure compressor.

Abstract: Method and unit for generating energy with improved efficiency. A Brayton cycle unit includes a multistage compressor configured to compress a flowing medium; a first heat exchanger fluidly connected to the multistage compressor and configured to transfer heat from a working medium passing the first heat exchanger to the compressed flowing medium; an expander fluidly connected to the first heat exchanger and configured to expand the heated compressed flowing medium for producing a rotation of a shaft of the expander; and a second heat exchanger fluidly connected between the expander and the compressor and configured to remove heat from the expanded flowing medium. A path of the flowing medium through the unit is closed. At least one inter-cooler mechanism between first and second stages of the multistage compressor is configured to cool the flowing medium to a predetermined temperature.

Abstract: A compressor assembly has a fluid inlet positioned to facilitate the passage of a fluid. The compressor assembly includes a compressor housing defining a compressor inlet and an impeller rotatably supported at least partially within the compressor housing. The impeller includes an inducer portion. A fluid treatment member is disposed adjacent the compressor housing and between the compressor inlet and the inducer portion and an inlet vane assembly I disposed adjacent the compressor inlet and includes a plurality of vanes. Each of the vanes is movable between a first position and a second position to control the quantity of fluid that passes to the impeller.

Abstract: A heat exchanger arrangement for a gas turbine engine. The arrangement including a flow path within an outer cowl, which flow path locates a heat exchanger part way therealong. A valve is provided at an inlet end of the flow path to selectively receive fluid into the flow path from outside of the cowl and/or from a pressurised fluid flow. An exit from the flow path includes a plenum chamber to receive exhausted coolant flows from the heat exchanger and possibly other exhaust flows. The heat exchanger exhaust flow is then utilised to provide cooling to engine structures.

Abstract: A heat exchanger apparatus includes: (a) an airfoil having opposed pressure and suction sides, a root, a tip, and spaced-apart leading and trailing edges; and (b) a plenum integrally formed within the airfoil which is configured to receive a flow of circulating working fluid; and (c) inlet and outlet ports communicating with the plenum and an exterior of the airfoil.

Abstract: A turbomachine is provided. The turbomachine includes a rotor, a stator and a plurality of blade discs mounted on the rotor. The rotor includes a turbulator cylinder where a plurality of turbulators are provided on a curved surface of the turbulator cylinder and the stator includes an annular shroud extending around the turbulator cylinder. The plurality of turbulators increase a heat transfer to a coolant flowing between the adjacent opposed surfaces of the turbulator cylinder and the annular shroud.

Abstract: A wind turbine is provided having a gearbox containing a lubrication medium, a pump for circulating the lubrication medium, and a gearbox lubrication suction pipe for transporting the lubrication medium from the gearbox to the pump. A heater is in thermal connection to, at least a portion of, the gearbox lubrication suction pipe. This heater is used to heat the lubrication medium contained within the gearbox lubrication suction pipe to a temperature where damage to the pump is avoided.

Abstract: A casing provided centrally with a sealed structure chamber. Small-sized separate four filter elements are arranged each on opposite sides of the chamber such that inflow air from a suction section into the casing is introduced via the filter elements into the chamber. Each filter element is detachably fitted over a filter-element mount having openings at its outer periphery. Upon filter-element replacement, the filter elements are replaced individually by opening a window. An integral cast casing having compressing sections and compressed air passages integrally fabricated therewith by casting is formed with receptacles for first and second intercoolers and an aftercooler. The intercoolers and aftercooler are received in the receptacles. Outlets of the intercoolers are connected with suction sides of second- and third-stage compressors through second- and third-stage suction pipes, respectively. A blowoff silencer is arranged between the integral cast casing and an oil tank.

Abstract: In an axial-centrifugal compressor, the rotor of which includes an impeller, axial play is controlled by a special air ventilation to the rotor, by a circuit including two parallel arms, flow rates of which are both controlled by respective veins, and moreover the temperature in one of them is changed by a heat exchanger. The ventilation air is thus controlled, both in terms of temperature and flow rate.

Abstract: A casing provided centrally with a sealed structure chamber. Small-sized separate four filter elements are arranged each on opposite sides of the chamber such that inflow air from a suction section into the casing is introduced via the filter elements into the chamber. Each filter element is detachably fitted over a filter-element mount having openings at its outer periphery. Upon filter-element replacement, the filter elements are replaced individually by opening a window. An integral cast casing having compressing sections and compressed air passages integrally fabricated therewith by casting is formed with receptacles for first and second intercoolers and an aftercooler. The intercoolers and aftercooler are received in the receptacles. Outlets of the intercoolers are connected with suction sides of second- and third-stage compressors through second- and third-stage suction pipes, respectively. A blowoff silencer is arranged between the integral cast casing and an oil tank.

Abstract: A ground based power generation system contains at least two compressor stages, a combustion stage and a turbine stage. An intercooler is positioned between the two compressor stages and a regenerator is positioned between the compressor stages and the combustion stage. The combustion stage contains at least one of a pulse detonation combustor and constant volume combustor. Downstream of the combustion stage is the turbine stage. Heat for the regenerator is supplied from the turbine stage. Further, a bypass flow device is included which re-directs flow upstream of the combustion stage to downstream of the combustion stage and upstream of the turbine stage.

Abstract: Compressor impellers, compressor sections, and methods of manufacturing compressor impellers and cooling the compressor impellers are provided. In an embodiment, and by way of example only, a compressor impeller includes a bore section and a rim section. The bore section comprises a first nickel-based alloy and includes an inner disk portion and a first plurality of blade portions extending therefrom. The rim section comprises a second nickel-based alloy and includes an outer disk portion and a second plurality of blade portions.

Abstract: A gas turbine engine is provided with a first heat exchanger associated with a cooling air flow to deliver cooling air to a turbine section. A second heat exchanger is associated with a fuel supply line for delivering fuel into a combustion section. An intermediate fluid cools air at the first heat exchanger and heats fuel at the second heat exchanger.

Abstract: An apparatus for distributing a fluid in a gas flow path inside a turbomachine, comprising: a device for introducing the fluid into the gas flow path; and wherein the device is positioned within the gas flow path. A method for installing an apparatus that will distribute a fluid in a gas flow path inside a turbomachine, the method comprising: machining a casing groove along an inner surface of a casing; machining at least one port into the casing that is in fluid communication with the casing groove; machining an internal cavity in at least one stator blade that is in fluid communication with the casing groove; machining at least one orifice, that is in fluid communication with the internal cavity, on an orifice surface of the stator blade; and coupling a fluid supply to the at least one port.

Abstract: An improved combustion air charger, such as a turbocharger or a supercharger, includes a housing (10) having a rotary shaft (18) journalled therein. At least one compressor wheel (20,22) is located on the shaft (18). The housing (10) includes an ambient inlet (30) as well as a compressed air outlet (32) and a heat exchanger (36) is located between at least one of the compressor wheels (20) and the outlet (32) and is arranged so that air flow through the heat exchanger (36) is generally in the radially inward direction.

Abstract: A method for operating a gas turbine engine, including a first compressor, a second compressor, a combustor and a turbine, coupled together in serial flow arrangement, and an intercooler coupled between the first compressor and the second compressor, the intercooler including a first heat exchanger and a second heat exchanger. The method includes channeling compressed airflow from the first compressor to the first heat exchanger, extracting energy from the compressed airflow using a first working fluid flowing through the first heat exchanger to facilitate reducing an operating temperature of the compressed airflow and to facilitate increasing an operating temperature of the first working fluid, and channeling the first working fluid to a process heat exchanger, and channel the compressed airflow form the first heat exchanger to the second compressor.

Abstract: In a method and a device for intermediate cooling during compression in a gas turbine system, the gas turbine system includes at least one first (1) and one second compressor (2), a combustion chamber (3), and a turbine (4). At least one intermediate cooler (9) is located between the first (1) and second compressor (2). The intermediate cooling takes place at least in part or for the most part isentropically.

Abstract: A compact rotary compressor unit within internal intercooling includes a rotary shaft (10) with at least one compressor wheel (14,16) mounted thereon for rotation therewith. The compressor wheel (14,16) has an inlet end (18) of relatively small diameter and a radial discharge end (20) of relatively large diameter. A nominally donut-shaped intercooling heat exchanger (42) is centered about the shaft (10) to receive compressed air from the compressor wheel and cool the same. Both the compressor wheel (14,16) and the heat exchanger (42) are confined in a housing (28).

Abstract: A method for operating a gas turbine engine including a first compressor, a second compressor, a combustor and a turbine, coupled together in serial flow arrangement. The method includes channeling compressed airflow discharged from the first compressor to a heat exchanger having an airstream flowing therethrough, channeling an evaporatively cooled airstream into the heat exchanger to facilitate reducing an operating temperature of the heat exchanger, and extracting energy from the compressed airflow using the heat exchanger airstream to facilitate reducing a temperature of the compressed airflow and channeling the compressed airflow from the heat exchanger to the second compressor.

Abstract: A rotary compressor machine, such as a combustion air charger, includes a rotatable shaft (18) having at least one compressor wheel (20,22) thereon and disposed within a housing (12,14). A donut-shaped heat exchanger (36) is located within the housing (12,14) between the compressor wheel (22) and an outlet (32) from the housing and has radially inner and outer peripheries (40,42). The outer periphery (40) defines an inlet for the heat exchanger (36) for gas discharged by the compressor wheel (20). The heat exchanger is provided with radially inner and outer flow paths defined by tubes (92) and includes a combined manifold and tank (44) which is secured and sealed to a header plate (88) receiving the tubes (92). The combined manifold and tank (44) includes first, second and third axially spaced walls (96,98,100) with each having a central opening (110,112,114).

Abstract: Improved efficiency is obtained in a rotary machine having a rotary shaft (18) mounting a compressor wheel (20) that discharges into a heat exchanger (36) having a core (82) with a central opening (42) in surrounding relation to the shaft (18). The heat exchanger (36) includes a coolant tank (90) on one side of the core (82) and in fluid communication with the same which serves as one boundary of radially extending space (68) through which a gas is discharged by a compressor wheel (20). A deswirling vane structure (80) causes gas discharged by the compressor wheel (22) to move radially outward within the space (68) and is formed of a material of good thermal conductivity and thermally bridged to the tank (90) to conduct heat thereto to be rejected to coolant in the tank.

Abstract: Improved efficiency is obtained in a rotary machine having a rotary shaft (18) mounting a compressor wheel (20) that discharges into a heat exchanger (36) having a core (82) with a central opening (42) in surrounding relation to the shaft (18). The heat exchanger (36) includes a coolant tank (90) on one side of the core (82) and in fluid communication with the same which serves as one boundary of radially extending space (68) through which a gas is discharged by a compressor wheel (20). A deswirling vane structure (80) causes gas discharged by the compressor wheel (22) to move radially outward within the space (68) and is formed of a material of good thermal conductivity and thermally bridged to the tank (90) to conduct heat thereto to be rejected to coolant in the tank.

Abstract: A turbo compressor, comprising two (2) pieces of rotation shafts, being disposed in parallel with each other, wherein impellers are attached on both ends of one of the rotation shafts, thereby to build up a first-stage compressor and a second-stage compressor, while an impeller on one end of the other rotation shaft, thereby to build up a third-stage compressor. In a lower side of each of the compressors, an intercooler and an after-cooler are disposed in alignment with, for cooling down an operation gas compressed in each stage. The operation gas is guided into the first-stage compressor on a side opposing to a motor, into the second-stage compressor on a side of the motor, and into the third-stage compressor on the side opposing to the motor, in the order thereof.

Abstract: A turbo compressor, comprising two (2) pieces of rotation shafts, being disposed in parallel with each other, wherein impellers are attached on both ends of one of the rotation shafts, thereby to build up a first-stage compressor and a second-stage compressor, while an impeller on one end of the other rotation shaft, thereby to build up a third-stage compressor. In a lower side of each of the compressors, an intercooler and an after-cooler are disposed in alignment with, for cooling down an operation gas compressed in each stage. The operation gas is guided into the first-stage compressor on a side opposing to a motor, into the second-stage compressor on a side of the motor, and into the third-stage compressor on the side opposing to the motor, in the order thereof.

Abstract: Retrofit apparatus is provided for rapidly exhausting air pressure from one or more intercoolers connected in fluid communication between two low pressure heads of an air compressor and a high pressure head of the compressor. The retrofit apparatus comprises an unloader valve, a center header for commonly connecting the intercoolers to the high pressure head, and means for connecting the unloader valve to the center header to effect rapid unloading of the header and the intercoolers connected thereto of pressurized air when the valve receives a compressor unload signal.

Abstract: A process gas compressor for the stepwise compression of process gases with increased percentage of hydrogen sulfide (H2S), with an H2S-uncritical area and an H2S-critical area, in the housing (5) of which impellers (3) and (2) with a direction of flow to the right (7) and, after cooling (6), impellers (2) with a direction of flow to the left (8) are arranged on a shaft (1), wherein the impellers (3) and (2) are provided with blade ends (4). The transition from the uncritical H2S area to the critical H2S area takes place after the outlet of the first or second larger impeller (3) on the shaft on the left. This is followed by another impeller (2) with a direction of flow to the right (7), which is already located in the critical H2S area. The precompressed process gas is subsequently sent to a cooler (6) before it enters the impellers (2) in the critical H2S area of the process gas compressor at the second gas inlet stage (8) and leaves it at the housing outlet (9).

Abstract: A compact heat exchanger system 52 for a duct 32 of a gas turbine engine 10 is disclosed, the heat exchanger system being disposed between two locations having an adverse pressure gradient. Various construction details which reduce the impact of the system 52 on engine efficiency, provide acceptable levels of drag, and reduce the possibility of foreign object damage are developed. In one embodiment the system has a low profile inlet 58 adjacent the inner wall 36 of a fan duct and has a flow path 56 extending from the inlet 58 to the outlet 62 which is continuous under all operating conditions of the engine.

Abstract: The present invention includes an intercooled cycle gas turbine. The intercooled cycle gas turbine is supercharged to improve performance. Pereformance is defined in terms of thermal efficiency and mass specific power, the turbine defining a cycle with a peak cycle pressure and a peak cycle temperature. The turbine includes an intercooler for intercooling the turbine, wherein placement of the intercooler within the cycle divides the cycle into a first compression stage and a second compression stage. The intercooler placement r=1/2 ln P.sub.super /ln(P.sub.peak /P.sub.super). The first compression stage and the second compression stage have an unequal pressure ratio.

Abstract: In a method of operating a combined-cycle plant which is based on a gas-turbine group, the compressor unit of this same gas-turbine group is equipped with an intercooler (9). By detecting parameters which comprise at least the ambient temperature (T), the air humidity (.phi.) of intake air (7) and the outlet pressure (Pic) of the intercooler (9), and by feeding the same to a computer (15), regulation is initiated by the latter, which regulation acts on members (17, 18) in the coolant circuit (13, 13a) between the intercooler (9) and a heat sink (14). The dew-point temperature of the cooled air (10), compressed to an intermediate pressure, downstream of the intercooler (9) is thereby influenced.

Abstract: An integrally intercooled axial compressor where the axial compressor passes cooling water through one or more stator assemblies and/or an internal air-to-water heat exchanger located in the gas flow path of the compressor to reduce the temperature of the gas as it is compressor in different stages of the axial compressed.

Abstract: Rotary fluid handling apparatus employing a wheel to provide multi-stage compression or expansion. A wheel having a first set of vanes includes a shroud about those vanes with a second set of vanes outwardly of the shroud. One set of vanes provides for low specific speed flow while the other set of vanes provides for high specific speed flow. A transfer passage interconnects the outlet of the first stage with the inlet of the second stage. The difference in temperature between the inlet flow to the system and the outlet flow from the system may be exchanged to increase efficiency. The multi-stage wheel and associated passages may be configured for either compression or turboexpansion.

Abstract: A gas turbine engine with first and second axial flow compressors and an intercooler therebetween is provided with a diffuser to diffuse the air flow leaving the downstream end of the first axial flow compressor at a first radial distance from the axis to the upstream end of the intercooler at a second radial distance from the axis. The diffuser comprises a first radially extending wall, a second radially extending wall and a plurality of diffuser vanes extending therebetween which define a plurality of generally radially extending diffusing passages. The vanes are wedge shaped. This arrangement provides diffusion in a short axial length.