Abstract: A preform CMC article is disclosed comprising an interior ply structure having at least one interior CMC ply including at least one longitudinal CMC ply disposed along the article length, an exterior shell ply forming an article surface and having at least one exterior CMC ply substantially surrounding the interior ply structure, and at least one wicking portion in which the interior ply structure penetrates the exterior ply shell with an exposed edge of the longitudinal CMC ply disposed at the article surface. A CMC article is disclosed including the interior ply structure and the exterior ply shell, wherein the longitudinal CMC ply includes an exposed edge disposed at the surface of the CMC article. A method for forming the CMC article is disclosed including wicking a melt infiltration agent into the article through the wicking portion into the interior ply structure along the longitudinal CMC ply.

Abstract: A turbine blade of a gas turbine engine is described which includes an airfoil extending away from the hub platform to a blade tip. The airfoil defines a leading edge, a trailing edge, and a span-wise length extending between the platform and the blade tip. A hot-corrosion-resistant coating is located on the leading edge of the airfoil within a radially inner portion thereof, the radially inner portion extending away from the hub platform a desired distance along the span-wise length.

Abstract: A device for dismantling a blade from a turbine, the turbine including a set of blades, the device including: a holding element including a blocking surface; a dismantling opening; an attachment system configured to attach the holding element to a shaft of the turbine, the attachment system producing a pivot connection between the holding element and the shaft of the turbine, the defining of an angular position of the holding element allowing a first function of dismantling at least one blade facing the dismantling opening to be carried out and allowing a second function of blocking a set of blades facing the blocking surface to be carried out.

Abstract: In a featured embodiment, a fan rotor includes a platform. Clevises extend radially inwardly of the platform. Each clevis has an aperture. A hub has hub lugs positioned intermediate spaced ends of the clevises, and apertures. A pin extends through the apertures in the hub and the clevises to connect the platform to the hub. The apertures in the clevises are formed to have an inner surface for supporting the pin. A method of forming a fan blade platform is also disclosed.

Abstract: A method and system for controlling a pitch of blades of a fan assembly having a centerline axis of rotation is provided. The system includes a pitch change mechanism (PCM) including a hydraulic actuator positioned axisymmetric with respect to the fan assembly and configured to angularly displace the blades of the fan assembly between a first position and a second position. The PCM further includes a plurality of hydraulic fluid supply lines coupled in flow communication between the hydraulic actuator and a hydraulic fluid transfer sleeve, the hydraulic fluid transfer sleeve configured to transfer a flow of pressurized hydraulic fluid across a gap between a stationary member of the hydraulic fluid transfer sleeve and a rotatable member of the hydraulic fluid transfer sleeve.

Abstract: A combustor section of a gas turbine engine has a diffuser case with a structural cone having variable wall thicknesses strategically located for reducing localized stress in the cone.

Abstract: A steam turbine having an inflow ring channel which is connected to an inflow connecting piece in terms of flow technology. The inflow connecting piece is designed in such a way that an incoming flow is first slowed down, subsequently accelerated and simultaneously deflected.

Abstract: A component for a gas turbine engine is described. The component may comprise a body portion formed from a metallic material. The component may further comprise an abrasive surface forming at least one surface of the body portion, and the abrasive surface may be configured to abrade an abradable material. The abrasive surface may be formed from electrical discharge machining of the metallic material.

Abstract: The present application provides a turbine nozzle including an airfoil shape. The airfoil shape may have a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table I. The Cartesian coordinate values of X, Y and Z are non-dimensional values from 0% to 100% convertible to dimensional distances in inches by multiplying the Cartesian coordinate values of X, Y and Z by a height of the airfoil in inches. The X and Y values, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z. The airfoil profile sections at Z distances may be joined smoothly with one another to form a complete airfoil shape.

Abstract: A labyrinth seal system comprises a knife element and a stator element, the knife element having a plurality of teeth radially extending from a base and the stator element having a radially inner surface configured to interact with the plurality of teeth to create a seal. The knife element is axially constrained by and rotationally coupled to a turbine component, but has a degree of freedom in the radial direction with respect to that component.

Abstract: A gas turbine membrane seal is disclosed. The gas turbine membrane seal includes a membrane, the membrane configured and arranged to extend from a first gas turbine component to a second gas turbine component and to separate two volumes, and an anti-fretting part configured and arranged to be attached to the first gas turbine component. A face of the anti-fretting part is adjacent to the membrane, and the face of the anti-fretting part is convex. Further embodiments of the gas turbine membrane seal are also described, along with a gas turbine having the gas turbine membrane seal and a retrofitting method.

Abstract: A shroud sealing arrangement for a gas turbine engine, which comprises a static shroud assembly mounted to an engine case and having a platform surrounding a rotatable airfoil array. The platform has an inner side and an outer side and extends from a leading edge to a trailing edge. A shroud support structure mounts the shroud platform to the case. A circumferential groove is defined on the outer side of the shroud platform proximal to one of the leading edge and the trailing edge. A sealing ring is set in the groove and adapted to seal cooling air from escaping directly to the gas path.

Abstract: A rim seal for a rotor of a gas turbine engine includes a seal portion extending circumferentially across a rim cavity of a rotor, the sealing portion configured to seal the rim cavity and a first foot portion extending radially inwardly from a first end of the sealing portion. A rotor assembly for a gas turbine engine includes a rotor disc and a plurality of rotor blades secured to the rotor disc defining a rim cavity between the rotor disc and a rim portion of the plurality of rotor blades. A rim seal is located in the rim cavity and includes a seal portion extending circumferentially across the rim cavity, the sealing portion configured to seal the rim cavity. The seal portion has an increasing radial thickness with increasing distance from a first end of the rim seal and from a second end opposite the first end.

Abstract: A blade outer air seal (BOAS) assembly includes a rotor blade configured to rotate about an axis. The BOAS assembly also includes a BOAS positioned radially outward from the rotor blade and having a forward-facing BOAS face. The BOAS assembly also includes a shroud block positioned radially outward from the BOAS, having an aft-facing shroud face, and being configured to support the BOAS. The BOAS assembly also includes a first bellows seal extending from the forward-facing BOAS face to the aft-facing shroud face and configured to reduce fluid leakage radially between the BOAS and the shroud block.

Abstract: A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a turbine section including a fan drive turbine, a geared architecture driven by the fan drive turbine, and a fan driven by the fan drive turbine via the geared architecture. At least one stage of the turbine section includes an array of rotatable blades and an array of vanes. A ratio of the number of vanes to the number blades is greater than or equal to about 1.55. A mechanical tip rotational Mach number of the blades is configured to be greater than or equal to about 0.5 at an approach speed.

Abstract: A borescope plug includes a threaded section that extends from a head section along an axis, the threaded section including a central passage along said axis. A spindle is located within the central passage. A multiple of detents are positioned in response to an axial position of the spindle along the axis.

Abstract: A containment for a continuous flow machine, in particular for a gas turbine, is disclosed. The containment has at least one annular housing with at least one axial section of lesser radial wall thickness and at least one axial section adjacent thereto of greater wall thickness, where the housing is designed and constructed so that the section of greater wall thickness is at a distance in the axial direction of the continuous flow machine from a trailing edge of a guide vane lying downstream in the direction of flow of the continuous flow machine, and extends downstream in the direction of flow of the continuous flow machine over a leading edge of the next downstream guide vane.

Abstract: A gas turbine engine is provided. The gas turbine engine comprising: a fan section having a fan; and a containment zone encircling the fan, the containment zone comprising: a ballistic liner composed of a plurality of ring segments located radially outward of the fan; wherein each of the plurality of ring segments include two opposing circumferential ends, and wherein the plurality of ring segments are arranged circumferentially around the fan section and the circumferential ends of each of the plurality of ring segments meet at joints to form the ballistic liner.

Abstract: A gas turbine engine comprising a gearbox, the gearbox comprising a sun gear, an annulus gear, a plurality of planet gears and a carrier, each planet gear being rotatably mounted in the carrier by at least one bearing, the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear, the sun gear, the planet gears and the annulus gear comprising gear teeth, the annulus gear having a length in the axial direction and an axially forward end and an axially rearward end and wherein the annulus gear is resiliently mounted to a supporting structure at both its axially forward and axially rearward ends.

Abstract: An acoustic damper includes a housing with an inlet aperture and an outlet aperture. The housing is configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture. The acoustic damper also includes a barrier member that is disposed within the housing. The barrier member is configured to be disposed within the gas flow and to dampen acoustic energy that propagates in an upstream direction generally from the outlet aperture toward the inlet aperture. The barrier member includes an outer structure that defines an interior volume of the barrier member. The interior volume is oriented toward the outlet aperture.

Abstract: One exemplary embodiment of this disclosure relates to a gas turbine engine including a component. The component includes a platform having a mateface on a circumferential side thereof. The platform including a core passageway configured to communicate fluid to the mateface.

Abstract: A turbine shroud segment comprises a body having an upstream end portion and a downstream end portion relative to a flow of gases through the gas path. A core cavity is defined in the body and extends axially from the upstream end portion to the downstream end portion. A plurality of cooling inlets is defined in the upstream end portion of the body for feeding coolant in the core cavity. A plurality of cooling outlets is defined in the downstream end portion of the body for discharging coolant from the core cavity. Pedestals are provided in the core cavity.

Abstract: A turbine engine for an aircraft which includes, in general, at least one assembly made up of a first part wherein a second part is attached with an attachment device including a milled head applied to the first part and a body engaging with the second part in order to clamp the parts. The recess of the head of such an attachment device requires a boss on the first part, which is complex and expensive to produce using conventional techniques. Such a boss can be replaced with a removable seat having an opening through which the body passes and forming a recess for the head, a bearing surface for the head, and abutment device applied to the first part in order to prevent a movement of the seat towards the second part.

Abstract: A stator assembly of a gas turbine engine according to an example of the present disclosure includes, among other things, a first shroud that extends about an axis to bound a flow path. The first shroud defines a first shroud opening. An airfoil has an airfoil body that extends from a first end portion. The first end portion is received in the first shroud opening and defines a pair of airfoil openings. At least one retention clip has an intermediate portion connecting a pair of elongated leg portions. The pair of elongated leg portions are received in the pair of airfoil openings such that the at least one retention clip limits movement of the airfoil relative to the first shroud. A method of assembling a stator assembly is also disclosed.

Abstract: A hanger for mounting an exhaust liner to an exhaust duct is provided. The hanger includes at least one cable, a cable flange, and a J-shaped flange. The at least one cable extends lengthwise between a first end and a second end. The cable flange has at least one cable aperture configured to receive a portion of the cable. The J-shaped liner flange is configured for attachment to the exhaust liner. The liner flange and cable flange are configured to mate with one another to prevent substantial relative motion between the cable flange and the liner flange in a first direction and in a second direction. The first and second directions are substantially orthogonal to one another.

Abstract: A turbine ventilation structure includes: an exhaust diffuser including inner and outer tubes to form an exhaust passage for exhaust gas; a strut extending across the exhaust diffuser from a housing to support a bearing inside the inner tube; a strut cover in the exhaust passage that covers the strut; and a connecting member disposed downstream of the strut cover and including a hollow portion to connect the housing and the inner tube. The housing includes a first intake port to introduce an air from outside. The strut cover has a discharge hole at a rear edge portion thereof. The turbine ventilation structure includes a first ventilation passage extending from the first intake port through the hollow portion, then extending from an inner end portion of the strut through between the strut and the strut cover, and the discharge hole, into the exhaust passage.

Abstract: A turbine and the method of operating the turbine when taking the turbine off-line includes transmitting power to a No. 1 shaft via a main motor to turn the turbine at an original turning speed, wherein the No. 1 shaft drives a No. 2 shaft; reducing a speed of the turbine; and when the speed of the turbine is reduced to a predetermined RPM, switching power transmission to the turbine from the No. 1 shaft to a No. 2 shaft, wherein the No. 2 shaft is driven by an auxiliary motor, and the No. 2 shaft drives the No. 1 shaft to turn the turbine at a slow turning speed less than the original turning speed.

Abstract: The invention relates to a steam turbine having a plurality of stages comprising a plurality of points of admission connected to a plurality of admission lines, a feed line connected to the plurality of admission lines and at least one extraction line, extending from an intermediate stage of the steam turbine, for extracting steam from the steam turbine. The at least one capacity line fluidly connects an admission lines and at least one extraction line so as to bypass the steam turbine, and is further configured to increase a swallowing capacity of the steam turbine as measured from the feed line upstream of the capacity line compared to the plurality of points of admission.

Abstract: The present disclosure relates to systems and methods that provide power generation using predominantly CO2 as a working fluid. In particular, the present disclosure provides for particular configurations for startup of a power generation system whereby the combustor may be ignited before the turbine is functioning at a sufficiently high speed to drive the compressor on a common shaft to conditions whereby a recycle CO2 stream may be provided to the combustor at a sufficient flow volume and flow pressure. In some embodiments, a bypass line may be utilized to provide additional oxidant in place of the recycle CO2 stream.

Abstract: A valve timing change device includes: a housing rotor (10); a vane rotor; a fastening bolt (40); and an advance angle oil passage communicating with an advance angle chamber and a delay angle oil passage communicating with a delay angle chamber, via oil passages which are open at intervals on an outer-circumferential surface of the fastening bolt. The vane rotor includes: a rotor body (20) formed of a material having a thermal expansion coefficient greater than that of the fastening bolt; and a rotor sleeve (30) that is formed of a material having a thermal expansion coefficient equal to that of the fastening bolt and is integrally incorporated such that the rotor sleeve does not contact a cam shaft and tightly contacts the outer circumferential surface (41a), in a region in which the advance angle oil passage (23a) and the delay angle oil passage (35) are blocked from each other.

Abstract: A rocker arm includes an outer arm having a first wall and a second wall and an inner arm which selectively pivots relative to the outer arm about a pivot shaft axis of a pivot shaft based on positioning of a lock pin. A lost motion spring includes an outer arm tang grounded to the outer arm and an inner arm tang grounded to the inner arm. A roller shaft is supported by the inner arm and extends toward the first wall. The roller shaft carries a roller which follows a camshaft. A roller retainer is carried by the roller shaft and is located between the roller and the first wall and includes a surface with which the inner arm tang is engaged to ground the lost motion spring to the inner arm, a roller shaft aperture containing the roller shaft, and a pivot shaft aperture containing the pivot shaft.

Abstract: A continuously variable valve duration apparatus may include a camshaft, a plurality of first cams and second cams of which a cam key is formed respectively thereto, and of which relative phase angles with respect to the camshaft are variable, a plurality of rotation rings mounted to the camshaft and of which a ring key is formed thereto respectively, a plurality of inner brackets transmitting rotation of the camshaft to the cam keys of the first cams and the seconds respectively, a plurality of slider housings of which each inner bracket is rotatable inserted therein, a support bracket connecting the slider housings and a control portion selectively moving the support bracket and moving positions of the slider housings so as to change rotation centers of the inner brackets.

Abstract: A variable valve lift actuator of an engine includes a first body that rotates within a predetermined angular range; a second body connected to or disconnected from the first body; a latching pin configured to project to or retract from the first body by passing through the second body to connect or disconnect the first body and the second body; a drive module connected to the latching pin through a connecting member to project or retract the latching pin; a rotary shaft disposed above the valve across both side walls of the first body and the second body such that the first body is rotatable; and a return spring installed on the rotary shaft to provide a restoring force to return the first body rotated by the high-speed cam to an original position thereof.

Abstract: A variable valve gear for an internal combustion engine of a motor vehicle has a cam carrier which is arranged on a camshaft in a manner which prevents relative rotation and allows axial movement between a first axial position and a second axial position and has a first cam and a second cam. The first cam is designed for a normal mode of the internal combustion engine, in which the first cam keeps a first exhaust valve open in the exhaust stroke. The second cam is designed for an engine braking mode of the internal combustion engine, in which the second cam initially keeps the first exhaust valve closed in the compression stroke and/or in the exhaust stroke and opens the first exhaust valve before reaching a top dead center of a piston movement.

Abstract: An outboard motor includes an internal combustion engine having an engine block with vertically-aligned first and second banks of piston-cylinders that extend at an angle with respect to each other so as to form a V-shape. A crankshaft extends along a vertical axis. Combustion in the first and second banks of piston-cylinders causes rotation of the crankshaft. First and second camshafts extend along the first and second banks of vertically-aligned cylinders, respectively. A flexible coupler couples the crankshaft to the first and second camshafts so that rotation of the crankshaft causes rotation of the first and second camshafts. A rotary idler is coupled to the flexible coupler such that rotation of the crankshaft causes rotation of the rotary idler. A lubricating pump is coupled to the rotary idler such that rotation of the rotary idler causes the lubricating pump to pump lubricant to the internal combustion engine.

Abstract: A valve group (10) is housed in a duct (40) of a pressurized oil circuit of a vehicle. The valve group (1) extends along an axis (X-X) including a valve body (11) axially fixed to the conduit (40) and an obturator (15) fitted axially movably, on the valve body (11). The obturator (15) has an exchanger aperture (153) through which oil flows to a heat exchanger (3) in the circuit and an auxiliary aperture (152) through which the oil flows to an auxiliary component of the circuit. The valve group (10) includes a pair of elastically yieldable elements (180) of a material selected from among the shape-memory alloys, operatively connected between the valve body (11) and obturator (15), and suitable, as a function of the oil temperature and/or the oil pressure, to axially move and to maintain the obturator (15) in a predefined axial position.

Abstract: The present invention relates to a replaceable fluid container for an engine comprising: a first reservoir for holding a fluid; a second reservoir for holding a composition to be added to the fluid; a fluid coupling adapted to provide fluidic communication between the first reservoir and a fluid circulation system of the engine; and a dose controller to provide a dose of the composition into the fluid for circulation in a fluid circulation system of the engine.

Abstract: To improve the oil separation performance in an oil separation device for an internal combustion engine. The oil separation device (10) comprises a gas liquid separation passage (56) internally defined by a lower wall, an upper wall and a pair of side walls, and extending in a horizontal direction, a gas inlet (54) and a gas outlet (63) provided on either end of the gas liquid separation passage, a plurality of lower partition walls (56H) projecting upward from the lower wall, and a plurality of upper partition walls (56J) projecting downward from the upper wall. The lower partition walls and the upper partition wall are tilted with respective the length wise direction in plan view so as to define a spiral passage. The lower wall is inclined with respect to a horizontal plane such that an upstream part of the lower wall is lower than a downstream part of the lower wall with respect to a direction of the swirl flow.

Abstract: In an internal combustion engine, the cylinder block includes a first blowby gas passage and a first oil return passage. The cylinder head includes a second blowby gas passage connecting the first blowby gas passage with a connection passage connected with a gas-liquid separator, an oil return chamber separated from a valve operating chamber and the second blowby gas passage by first and second partition walls, respectively, and provided with a first oil return hole connected with the gas-liquid separator, and a second oil return passage connecting the valve operating chamber with the first oil return passage. The first partition wall is formed with a second oil return hole connecting the oil return chamber with the valve operating chamber. The second partition wall is formed with a ventilation hole connecting the oil return chamber with the second blowby gas passage at a higher position than the second oil return hole.

Abstract: Synergized platinum group metals (SPGM) with ultra-low PGM loadings employed as close-coupled (CC) three-way catalysts (TWC) systems with varied material compositions and configurations are disclosed. SPGM CC catalysts in which ZPGM compositions of binary or ternary spinel structures supported onto support oxides are coupled with commercialized PGM UF catalysts and tested under Federal Test Procedure FTP-75 within TGDI and PI engines. The performance of the TWC systems including SPGM CC (with ultra-low PGM loadings) catalyst and commercialized PGM UF catalyst is compared to the performance of commercialized PGM CC and PGM UF catalysts. The disclosed TWC systems indicate that SPGM CC TWC catalytic performance is comparable or even exceeds high PGM-based conventional TWC catalysts, with reduced tailpipe emissions.

Abstract: A system for treating engine exhaust gas, which engine exhaust gas has a temperature of between T1 and T2, comprises a SCR reactor for converting NOx in a medium containing the engine exhaust gas into N2 and H2O. The SCR reactor has an inlet for receiving the medium and an outlet for outputting the NOx reduced medium. A first boiler unit has an outlet for outputting boiler exhaust gas (temperature greater than T3, T3>T1) from the first boiler unit. A mixing unit mixes the engine exhaust gas with the boiler exhaust gas to produce the medium. The mixing unit has a first inlet communicating with the engine for receiving the engine exhaust gas, a second inlet communicating with the outlet of the first boiler unit for receiving the boiler exhaust gas and an outlet for outputting the medium. The mixing unit outlet communicates with the inlet of the SCR reactor.

Abstract: In the engine device having an exhaust gas purification device which removes particulate matters in exhaust gas of the engine or nitrogen oxides in the exhaust gas of the engine, the exhaust gas purification device is firmly fixed to a support base, and an exhaust gas outlet pipe of the engine is provided with an exhaust connection portion which connects an exhaust gas inlet of the exhaust gas purification device, and a support base connection portion which connects the support base.

Abstract: An element frame for holding monoliths containing catalysts in the flow of exhaust gases from a combustion source, the element frame comprising two pairs of opposing walls, wherein the walls form a rectangular or square shape, an interior formed by the walls, an inlet end, an outlet end, at least one locking element, at least one mat and at least one monolith comprising an inlet, an outlet, four sides and at least one catalyst effective in reducing the concentration of one or more gases in the exhaust gas, wherein the at least one mat and the at least one monolith being positioned in the interior of the element frame so that there is at least one mat between the monolith and each adjacent wall, each locking element extending across the inlet end or outlet end of the element frame and being connected to two opposite sides of the element frame.

Abstract: A retaining material that can sufficiently maintain the function of retaining a pollution control element in a pollution control device at high temperature. In one aspect, the retaining material has a mat shape and contains inorganic fiber material, with the retaining material containing: a surface layer containing inorganic colloid particles; and an internal region positioned further to the inside than the surface layer, impregnated with inorganic colloid particles and organic binder; wherein the surface layer contains inorganic colloid particles at a higher concentration than the internal region; and the amount of inorganic colloid particles in the internal region is 1 mass % to 10 mass % based on the total mass of the retaining material.

Abstract: An exhaust treatment device is disclosed. The exhaust treatment device has a compact configuration that includes integrated reactant dosing, reactant mixing and contaminant removal/treatment. The mixing can be achieved at least in part by a swirl structure and contaminant removal can include NOx reduction.

Abstract: A mixer assembly for a vehicle exhaust system includes a mixer housing defining an internal cavity that is configured to receive engine exhaust gases and an upstream baffle that is positioned at an inlet end of the mixer housing. The upstream baffle comprises a plate having an open area that comprises a fixed geometric configuration through which exhaust gas enters the internal cavity. A valve is movable from a closed position toward an open position to provide a variable geometric configuration that changes the open area to reduce back pressure.

Abstract: A valve apparatus that opens/closes a flow path for fluids. The valve apparatus comprises a tubular valve seat, and a valve. The valve comprises a valve body and a peripheral part. The peripheral part extends around an outer circumference of the valve seat from a periphery of the valve body towards upstream of the flow path for fluids.

Abstract: A flameless industrial air heater comprising: a combustion engine having a drive shaft and a combustion exhaust gas conduit to direct hot exhaust gases away from the engine; a mixing chamber having an air inlet and being in fluid communication with the exhaust gas conduit to mix the hot exhaust gasses with air flowing into the mixing chamber to produce a warmed air stream; and a compressor connected to the drive shaft and being driven thereby, the compressor being downstream of the mixing chamber to receive the warmed air stream and to pressurize the warmed air stream for delivery to applications requiring heating.

Abstract: A gas turbine engine assembly may include a combustion chamber for igniting a fuel and air mixture that generates a core stream flow. The gas turbine engine may also include a hot section cowling for directing the core stream flow through the engine assembly. The hot section cowling may include an inside surface and an outside surface opposite the inside surface. The gas turbine engine assembly may additionally include a plurality of thermoelectric generator (TEG) assemblies that are thermally attached to the outside surface of the hot section cowling. Each TEG assembly may include a multiplicity of thermoelectric generator (TEG) devices that generate an electric current based on a temperature differential across each of the multiplicity of TEG devices. The TEG devices may include different materials that are used in different heat zones along the hot section cowling between the combustion chamber and an exhaust end of the engine.

Abstract: An exhaust handling system comprising: an exhaust pipe having an exhaust outlet, said exhaust outlet having a nozzle arranged to vent exhaust gas; at least one acceleration jet arranged to project an air flow at a velocity head greater than that of the vented exhaust gas; wherein the at least one acceleration jet and exhaust outlet are positioned to project the air flow so as to impinge on a path of said vented exhaust gas, and consequently transfer velocity head to the vented exhaust gas.