WO2000074831A1 - Method and device for mixing gases - Google Patents

Method and device for mixing gases Download PDF

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Publication number
WO2000074831A1
WO2000074831A1 PCT/IB2000/000767 IB0000767W WO0074831A1 WO 2000074831 A1 WO2000074831 A1 WO 2000074831A1 IB 0000767 W IB0000767 W IB 0000767W WO 0074831 A1 WO0074831 A1 WO 0074831A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
mixing chamber
nozzle
drive gas
mixing
Prior art date
Application number
PCT/IB2000/000767
Other languages
French (fr)
Inventor
Ivan Justus Rademeyer
Original Assignee
Aeroflo (Proprietary) Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aeroflo (Proprietary) Limited filed Critical Aeroflo (Proprietary) Limited
Priority to AU46062/00A priority Critical patent/AU4606200A/en
Publication of WO2000074831A1 publication Critical patent/WO2000074831A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/38—Introducing air inside the jet
    • F02K1/386—Introducing air inside the jet mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
    • B01F25/3133—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit characterised by the specific design of the injector
    • B01F25/31332—Ring, torus, toroidal or coiled configurations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/315—Injector mixers in conduits or tubes through which the main component flows wherein a difference of pressure at different points of the conduit causes introduction of the additional component into the main component
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
    • B64D33/04—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of exhaust outlets or jet pipes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/10—Mixing gases with gases

Definitions

  • THIS INVENTION relates to mixing gases. It relates more specifically to a method of mixing gases and to a gas mixing device.
  • a method of mixing gases including introducing a drive gas in a high speed drive gas flow stream annularly, generally longitudinally into a mixing chamber at an inlet end of the mixing chamber; causing a passive gas to be entrained or induced generally longitudinally within the annular drive gas flow stream at said inlet end of the mixing chamber; and causing the drive gas and the passive gas to mix within the mixing chamber.
  • Causing said passive gas to be entrained or induced into said drive gas flow stream may be from centrally within the annular drive gas flow stream.
  • Introducing said drive gas flow stream into the mixing chamber may be at an annular position inwardly spaced from a periphery of the mixing chamber.
  • the method may then include causing a passive gas to be entrained or induced also from outwardly of said annular drive gas flow stream at said inlet end of the mixing chamber.
  • said passive gas caused to be entrained or introduced from within the annular drive gas flow stream and said passive gas caused to be entrained or introduced from outwardly of said annular drive gas flow stream may be the same passive gas from a common source.
  • Said passive gas may be ambient air, the method including placing said inlet end of the mixing chamber in communication with the atmosphere.
  • the method may include directing said drive gas flow stream into the mixing chamber via an annular, longitudinally directed nozzle at or toward the periphery of the mixing chamber at said inlet end .
  • Said nozzle may be a converging nozzle, the method including accelerating said drive gas flow stream when introducing it into the mixing chamber.
  • the method may include rotating said drive gas annularly to cause said drive gas flow stream introduced generally longitudinally into the mixing chamber to have also a rotational component of flow.
  • said drive gas may be hot exhaust gas from a combustion motor
  • said passive gas may be cold ambient air
  • mixing of the gases in the mixing chamber may form a cool mixture having a reduced infra-red signature compared to the hot exhaust gas
  • said drive gas may be high pressure, high temperature air bled off downstream of a compressor of a gas turbine motor of an aircraft
  • said passive gas may be cold, ambient air
  • mixing of the gases in the mixing chamber may produce a mixture appropriate for inhalation by humans, the method including introducing the mixture into a cabin of said aircraft.
  • a mixing device including a mixing chamber having an inlet end and an opposed exhaust end; an annular nozzle toward said inlet end directed longitudinally along the mixing chamber, the inlet nozzle having connection means for connection to a source of drive gas under pressure; an inlet opening annularly adjacent the annular nozzle, said inlet opening being in communication with a source of a passive gas to cause, in use, said passive gas to be entrained or induced into the mixing chamber.
  • Said inlet opening may be inwardly adjacent the annular nozzle. Instead, said inlet opening may be outwardly adjacent the annular nozzle.
  • said inlet opening may be both inwardly adjacent and outwardly adjacent the annular nozzle.
  • the inlet opening may be arranged to be open to the atmosphere, said source of passive gas then being the atmosphere and said passive gas then being ambient air.
  • said nozzle may be a converging nozzle to cause the drive gas to accelerate to be introduced into the mixing chamber at high speed in use.
  • the mixing device may include an annular plenum upstream of said nozzle, the connection means for the nozzle being on the plenum for connection to the source of drive gas under pressure.
  • connection means may include a nipple or conduit extending transversely of an axis of the plenum
  • said nipple or conduit may extend generally tangentially to said plenum, in use to guide said drive gas under pressure correspondinglygenerally tangentially into the plenum to cause rotation of said drive gas in the plenum and to cause said drive gas to be introduced into the mixing chamber in a generally longitudinal drive gas flow stream having a rotational component of flow.
  • Said mixing chamber may extend longitudinally in the direction of flying of the aircraft, and said exhaust conduit may extend transversely.
  • a mixing device as herein described, and an aircraft having a gas turbine motor including a compressor for compressing ambient air prior to combustion, the aircraft including a filter arrangement in which, in use, a scavenge air flow stream laden with dust or other particles and a filtered air flow stream purged of dust and other particles to provide filtered inlet air for the gas turbine engine are generated, in which combination said compressor is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to said gas turbine motor to bleed off a small portion of compressed, high temperature air downstream of the compressor and upstream of a combustion chamber of the gas turbine motor, and in which combination said inlet opening is communicated with said filter arrangement to collect said scavenge air flow to be entrained or induced into said drive gas flow stream.
  • Figure 1 shows, in axial section, a first embodiment of a mixing device in accordance with the invention
  • Figure 2 shows an end view in a downstream direction of the mixing device of Figure 1 ;
  • Figure 3 shows, in side view, another embodiment of a mixing device in combination with a gas turbine motor;
  • Figure 4 shows, in side view, a further embodiment of a mixing device
  • Figure 5 shows, in side view, a combination of a gas turbine motor having a filtered inlet, and a mixing device.
  • reference numeral 1 0 indicates schematically an extremity of a fuselage of an aircraft which has an exhaust conduit 1 2 extending transversely from a motor of the aircraft.
  • Reference numeral 1 3 generally indicates a mixing device in accordance with the invention.
  • the mixing device 1 3 includes an elongate mixing chamber 1 6 arranged longitudinally adjacentthe fuselage 10
  • the mixing chamber 1 6 may be cylindrical, conveniently round cylindrical.
  • an exhaust end thereof may be flattened, as is known in the art of infra red signature reduction to present a shallower, albeit wider, target for infra red sensing means.
  • a plenum 1 which can best be seen in Figure 2 and which is operatively communicated with the exhaust conduit 1 2.
  • hot exhaust gas flows via the exhaust conduit 1 2 into the plenum 14.
  • a nozzle 1 5 forms an integral part of the plenum 14.
  • the nozzle 1 5 is an annular nozzle which is directed longitudinally into the mixing chamber 1 6. In this embodiment it is located immediately inward of a periphery of the mixing chamber 1 6
  • the plenum 1 4, the nozzle 1 5 and the mixing chamber 1 6 are integrated
  • the exhaust gas is ejected annularly, longitudinally into the mixing chamber 1 6 via an annular opening 1 8 of the nozzle 1 5.
  • a central opening generally indicated by reference numeral 20 and which is in communication with ambient air.
  • the shape of the nozzle 1 5 forms an aerodynamic mouth for the central opening 20.
  • the high speed exhaust gas generally indicated by reference numeral 22 which flows into the mixing chamber 1 6 via the annular opening 1 8 creates an annular area of low pressure, in accordance with the principle of Bernoulli, which entrains or induces ambient air to flow in an airflow stream as indicated by reference numeral 24 via the central opening 20 into the mixing chamber 1 6.
  • the hot exhaust gas which enters the mixing chamber annularly peripherally is mixed with the cold ambient air which enters the mixing chamber longitudinally centrally to form a coo! mixture which is exhausted from the mixing chamber 1 6 as indicated at 26.
  • the cool mixture reduces the infra-red signature of the aircraft as mentioned above
  • the exhaust conduit 1 2 in the aircraft of Figures 1 and 2, extends transversely. It is thus highly advantageous to terminate the exhaust conduit in the annular plenum from which the exhaust gas can be ejected annularly longitudinally. It is an advantage that a change in direction of flow of the exhaust gas takes place via the plenum into the nozzle
  • the arrangement has the added advantages that the exhaust gas conduit need not include a corner or bend, that the exhaust gas conduit does not obstruct flow of ambient air into the central opening, that the hot exhaust gas is not present in the form of a concentrated hot core but rather in the form of a thin annular layer of large diameter, that the arrangement is structurally simple, and that the nozzle forms an integral part of the mixing device thus obviating problems associated with interfacing between the nozzle and mixing chamber as experienced in conventional arrangements.
  • FIG. 1 Another embodiment of a mixing device is generally indicated by reference numeral 1 1 3. It is similar, even identical, in many respects to the mixing device 1 3 of Figures 1 and 2.
  • the mixing device 1 1 3 is particularly suitable to provide warm ventilation air to a cabin of an aircraft such as a helicopter.
  • the mixing device 1 1 3 is used in combination with a gas turbine motor 100 having a compressor 1 02.
  • Hot air at high pressure is bled off immediately downstream of the compressor 1 02 of the gas turbine motor 1 00 of the aircraft.
  • Such bleed air is conducted in a bleed air conduit 1 1 2 into a plenum 1 1 4 forming part of the mixing device 1 1 3.
  • the plenum 1 1 4 incorporates an annular nozzle 1 1 5 which is directed longitudinally via an annular nozzle opening 1 1 8 into a mixing chamber 1 1 6
  • Ambient air which is cold, is entrained or induced as indicated by reference numeral 1 24 via a central opening 1 20 centrally within the annular nozzle 1 1 5, into the mixing chamber 1 1 6.
  • the hot bleed air (acting as the drive gas 1 22) and the cold ambient air 1 24 are mixed in the mixing chamber 1 1 6 to leave the mixing chamber 1 1 6 as a warm ventilation air mixture 1 26 suitable for inhalation by occupants of the cabin of the aircraft.
  • nozzle opening 1 1 8 is provided at a pitch circle having a diameter, thus ensuring that a mixing interface between the annular flow stream 1 22 of the hot air and the periphery of the opening 1 20 is of a large area or along a long linear dimension i.e. corresponding to the circumference of the diameter.
  • the arrangement of Figure 3 is much less noisy than conventional arrangements.
  • the arrangement provides a large (i.e. long, equal to the circumference of the annulus) interface with the ambient air which the Applicant expects to reduce noise, thus reducing an acoustic signature of the aircraft and enhancing the comfort of the occupant(s) .
  • This is particularly important bearing in mind the high pitched or high frequency, piercing or penetrating nature of the air when it leaves a small opening at high speed .
  • Other advantages of this arrangement are structural simplicity, easy locating of the nozzle, and no obstruction in front of the central opening inhibiting flow of the ambient air
  • a developed embodiment of a mixing device in accordance with the invention is generally indicated by reference numeral 21 3
  • the mixing device 21 3 is similar in many respects to the mixing devices of Figures 1 and 3 described above, like reference numerals refer to like components or features and emphasis will merely be placed on three important developments embodied in the device of Figure 4, without describing it in detail.
  • the conduit 21 2 by means of which drive gas under pressure is conducted to the device 21 3, enters the annular plenum 21 4 tangentially as opposed to radially as shown in Figure 2 for the device 1 3 This has the effect that the drive gas is rotated annularly, le it is swirled, within the plenum 21 4 which rotational component of flow is retained while flowing through the nozzle 21 5 and into the mixing chamber 21 6
  • annular nozzle 21 5 is a converging nozzle thus accelerating the drive gas in the drive gas flow stream as it is directed into the mixing chamber This enhances the Bernoulli effect and enhances entrainment or inducement of the passive gas into the mixing chamber.
  • the nozzle 21 5 is annularly spaced inwardly of an outer periphery of the mixing chamber 21 6.
  • passive gas is induced both radially outwardly of the nozzle 21 5 and inwardly of the nozzle 21 5, thus nearly doubling the interface between the drive gas and the passive gas (it is borne in mind that the diameter and thus also the circumference of the nozzle outlet 21 8 is smaller than those of the periphery of the mixing chamber 21 6 and thus of those which a nozzle at the periphery of the mixing chamber would have) .
  • a mixing device 31 3 is combined with a gas turbine motor 300 including a compressor 302 and having a filter arrangement 304 to filter inlet air.
  • an inlet stream of filtered air is conducted into the compressor 302.
  • the filter arrangement 304 filters dust grit and other undesirable particulate matter which are carried by means of a scavenge stream 308 away from the filter arrangement 304 and away from the gas turbine motor 300 via a conduit 31 2.1 .
  • the mixing device 31 3 having a mixing chamber 31 6 is arranged such that high pressure air bled off from downstream of the compressor 302 via a conduit 31 2 is entered as a drive gas via an annular inlet nozzle 31 5 into the mixing chamber 31 6.
  • the scavenge stream 308 is communicated with a central nozzle having a nozzle opening 320 inwardly of the annular drive gas nozzle
  • the drive gas induces the scavenge flow stream 308 to flow into the mixing chamber 31 6, thus to be extracted from the filter arrangement 304.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Engineering & Computer Science (AREA)

Abstract

Gases are mixed in a mixing device having an elongate, tubular mixing chamber (16). At an inlet end of the mixing chamber (16), an annular nozzle (15) directs a drive gas under pressure longitudinally into the chamber (16). Inwardly, and optionally also annularly outwardly of the nozzle (15), a passive drive gas is induced or entrained to flow into the chamber (16) and to mix with the drive gas. Entrainment and mixing are enhanced by providing an interface between the drive gas and the passive gas over a large area, proportionally to a circumference of the nozzle (15).

Description

METHOD AND DEVICE FOR MIXING GASES
THIS INVENTION relates to mixing gases. It relates more specifically to a method of mixing gases and to a gas mixing device.
The Applicant expects this invention to be particularly advantageously applicable to certain aircraft applications.
In accordance with a first aspect of this invention, there is provided a method of mixing gases, the method including introducing a drive gas in a high speed drive gas flow stream annularly, generally longitudinally into a mixing chamber at an inlet end of the mixing chamber; causing a passive gas to be entrained or induced generally longitudinally within the annular drive gas flow stream at said inlet end of the mixing chamber; and causing the drive gas and the passive gas to mix within the mixing chamber.
Causing said passive gas to be entrained or induced into said drive gas flow stream may be from centrally within the annular drive gas flow stream.
Introducing said drive gas flow stream into the mixing chamber may be at an annular position inwardly spaced from a periphery of the mixing chamber. The method may then include causing a passive gas to be entrained or induced also from outwardly of said annular drive gas flow stream at said inlet end of the mixing chamber. Then said passive gas caused to be entrained or introduced from within the annular drive gas flow stream and said passive gas caused to be entrained or introduced from outwardly of said annular drive gas flow stream, may be the same passive gas from a common source. Said passive gas may be ambient air, the method including placing said inlet end of the mixing chamber in communication with the atmosphere.
Advantageously, the method may include directing said drive gas flow stream into the mixing chamber via an annular, longitudinally directed nozzle at or toward the periphery of the mixing chamber at said inlet end . Said nozzle may be a converging nozzle, the method including accelerating said drive gas flow stream when introducing it into the mixing chamber.
By way of development, the method may include rotating said drive gas annularly to cause said drive gas flow stream introduced generally longitudinally into the mixing chamber to have also a rotational component of flow.
In one method, said drive gas may be hot exhaust gas from a combustion motor, said passive gas may be cold ambient air, and mixing of the gases in the mixing chamber may form a cool mixture having a reduced infra-red signature compared to the hot exhaust gas.
In another method, said drive gas may be high pressure, high temperature air bled off downstream of a compressor of a gas turbine motor of an aircraft, said passive gas may be cold, ambient air, and mixing of the gases in the mixing chamber may produce a mixture appropriate for inhalation by humans, the method including introducing the mixture into a cabin of said aircraft.
In accordance with another aspect of this invention, there is provided a mixing device including a mixing chamber having an inlet end and an opposed exhaust end; an annular nozzle toward said inlet end directed longitudinally along the mixing chamber, the inlet nozzle having connection means for connection to a source of drive gas under pressure; an inlet opening annularly adjacent the annular nozzle, said inlet opening being in communication with a source of a passive gas to cause, in use, said passive gas to be entrained or induced into the mixing chamber.
Said inlet opening may be inwardly adjacent the annular nozzle. Instead, said inlet opening may be outwardly adjacent the annular nozzle.
Instead, said inlet opening may be both inwardly adjacent and outwardly adjacent the annular nozzle.
The inlet opening may be arranged to be open to the atmosphere, said source of passive gas then being the atmosphere and said passive gas then being ambient air.
Advantageously, said nozzle may be a converging nozzle to cause the drive gas to accelerate to be introduced into the mixing chamber at high speed in use. The mixing device may include an annular plenum upstream of said nozzle, the connection means for the nozzle being on the plenum for connection to the source of drive gas under pressure. Said connection means may include a nipple or conduit extending transversely of an axis of the plenum By way of development, said nipple or conduit may extend generally tangentially to said plenum, in use to guide said drive gas under pressure correspondinglygenerally tangentially into the plenum to cause rotation of said drive gas in the plenum and to cause said drive gas to be introduced into the mixing chamber in a generally longitudinal drive gas flow stream having a rotational component of flow.
In accordance with a further aspect of this invention, there is provided a combination of a mixing device as herein described, and an aircraft having a combustion motor including an exhaust conduit for exhausting products of combustion, in which combination said combustion motor via said exhaust conduit is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to an outlet of said exhaust conduit, and in which combination said inlet opening is communicated with the atmosphere.
Said mixing chamber may extend longitudinally in the direction of flying of the aircraft, and said exhaust conduit may extend transversely.
IN accordance with yet a further aspect of this invention, there is provided a combination of a mixing device as herein described, and an aircraft having a gas turbine motor including a compressor for compressing ambient air prior to combustion, in which combination said compressor is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to said gas turbine motor to bleed off a small portion of compressed, high temperature air downstream of the compressor and upstream of a combustion chamber of the gas turbine motor, and in which combination said inlet opening is communicated with the atmosphere, said exhaust end of the mixing chamber being communicated with a cabin of the aircraft to supply the cabin with air appropriate for inhalation by humans.
In accordance with yet another aspect of this invention, there is provided the combination of a mixing device as herein described, and an aircraft having a gas turbine motor including a compressor for compressing ambient air prior to combustion, the aircraft including a filter arrangement in which, in use, a scavenge air flow stream laden with dust or other particles and a filtered air flow stream purged of dust and other particles to provide filtered inlet air for the gas turbine engine are generated, in which combination said compressor is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to said gas turbine motor to bleed off a small portion of compressed, high temperature air downstream of the compressor and upstream of a combustion chamber of the gas turbine motor, and in which combination said inlet opening is communicated with said filter arrangement to collect said scavenge air flow to be entrained or induced into said drive gas flow stream.
The invention is now described by way of example with reference to the accompanying diagrammatic drawings. In the drawings
Figure 1 shows, in axial section, a first embodiment of a mixing device in accordance with the invention;
Figure 2 shows an end view in a downstream direction of the mixing device of Figure 1 ; Figure 3 shows, in side view, another embodiment of a mixing device in combination with a gas turbine motor;
Figure 4 shows, in side view, a further embodiment of a mixing device; and Figure 5 shows, in side view, a combination of a gas turbine motor having a filtered inlet, and a mixing device.
It is emphasized that the drawings are schematic to illustrate the principles of the invention. For example, hatching is generally, not shown .
With reference to Figures 1 and 2 of the drawings, reference numeral 1 0 indicates schematically an extremity of a fuselage of an aircraft which has an exhaust conduit 1 2 extending transversely from a motor of the aircraft.
Reference numeral 1 3 generally indicates a mixing device in accordance with the invention. The mixing device 1 3 includes an elongate mixing chamber 1 6 arranged longitudinally adjacentthe fuselage 10 The mixing chamber 1 6 may be cylindrical, conveniently round cylindrical. In other embodiments, an exhaust end thereof may be flattened, as is known in the art of infra red signature reduction to present a shallower, albeit wider, target for infra red sensing means.
At an upstream end of the mixing chamber 1 6, there is provided a plenum 1 which can best be seen in Figure 2 and which is operatively communicated with the exhaust conduit 1 2. Thus, hot exhaust gas flows via the exhaust conduit 1 2 into the plenum 14. A nozzle 1 5 forms an integral part of the plenum 14. The nozzle 1 5 is an annular nozzle which is directed longitudinally into the mixing chamber 1 6. In this embodiment it is located immediately inward of a periphery of the mixing chamber 1 6 In a preferred embodiment, the plenum 1 4, the nozzle 1 5 and the mixing chamber 1 6 are integrated
Thus, in use, the exhaust gas is ejected annularly, longitudinally into the mixing chamber 1 6 via an annular opening 1 8 of the nozzle 1 5.
Centrally within the nozzle 1 5, there is provided a central opening generally indicated by reference numeral 20 and which is in communication with ambient air. The shape of the nozzle 1 5 forms an aerodynamic mouth for the central opening 20.
In use, the high speed exhaust gas generally indicated by reference numeral 22 which flows into the mixing chamber 1 6 via the annular opening 1 8 creates an annular area of low pressure, in accordance with the principle of Bernoulli, which entrains or induces ambient air to flow in an airflow stream as indicated by reference numeral 24 via the central opening 20 into the mixing chamber 1 6.
The hot exhaust gas which enters the mixing chamber annularly peripherally is mixed with the cold ambient air which enters the mixing chamber longitudinally centrally to form a coo! mixture which is exhausted from the mixing chamber 1 6 as indicated at 26. The cool mixture reduces the infra-red signature of the aircraft as mentioned above
It is important to appreciate that the exhaust conduit 1 2, in the aircraft of Figures 1 and 2, extends transversely. It is thus highly advantageous to terminate the exhaust conduit in the annular plenum from which the exhaust gas can be ejected annularly longitudinally. It is an advantage that a change in direction of flow of the exhaust gas takes place via the plenum into the nozzle The arrangement has the added advantages that the exhaust gas conduit need not include a corner or bend, that the exhaust gas conduit does not obstruct flow of ambient air into the central opening, that the hot exhaust gas is not present in the form of a concentrated hot core but rather in the form of a thin annular layer of large diameter, that the arrangement is structurally simple, and that the nozzle forms an integral part of the mixing device thus obviating problems associated with interfacing between the nozzle and mixing chamber as experienced in conventional arrangements.
With reference to Figure 3, another embodiment of a mixing device is generally indicated by reference numeral 1 1 3. It is similar, even identical, in many respects to the mixing device 1 3 of Figures 1 and 2.
Like reference numerals are used to denote like features or components, and the mixing device 1 1 3 is not again described in detail. It is emphasized that, like the other Figures, Figure 3 is schematic. For example, the same scale is not used for the gas turbine motor and the mixing device
The mixing device 1 1 3 is particularly suitable to provide warm ventilation air to a cabin of an aircraft such as a helicopter. The mixing device 1 1 3 is used in combination with a gas turbine motor 100 having a compressor 1 02.
Hot air at high pressure is bled off immediately downstream of the compressor 1 02 of the gas turbine motor 1 00 of the aircraft. Such bleed air is conducted in a bleed air conduit 1 1 2 into a plenum 1 1 4 forming part of the mixing device 1 1 3. The plenum 1 1 4 incorporates an annular nozzle 1 1 5 which is directed longitudinally via an annular nozzle opening 1 1 8 into a mixing chamber 1 1 6
Ambient air, which is cold, is entrained or induced as indicated by reference numeral 1 24 via a central opening 1 20 centrally within the annular nozzle 1 1 5, into the mixing chamber 1 1 6. The hot bleed air (acting as the drive gas 1 22) and the cold ambient air 1 24 are mixed in the mixing chamber 1 1 6 to leave the mixing chamber 1 1 6 as a warm ventilation air mixture 1 26 suitable for inhalation by occupants of the cabin of the aircraft.
One particularly important advantage is that the nozzle opening 1 1 8 is provided at a pitch circle having a diameter, thus ensuring that a mixing interface between the annular flow stream 1 22 of the hot air and the periphery of the opening 1 20 is of a large area or along a long linear dimension i.e. corresponding to the circumference of the diameter. Thus, it is believed that the arrangement of Figure 3 is much less noisy than conventional arrangements.
It is an advantage that the arrangement provides a large (i.e. long, equal to the circumference of the annulus) interface with the ambient air which the Applicant expects to reduce noise, thus reducing an acoustic signature of the aircraft and enhancing the comfort of the occupant(s) . This is particularly important bearing in mind the high pitched or high frequency, piercing or penetrating nature of the air when it leaves a small opening at high speed . Other advantages of this arrangement are structural simplicity, easy locating of the nozzle, and no obstruction in front of the central opening inhibiting flow of the ambient air
With reference to Figure 4, a developed embodiment of a mixing device in accordance with the invention is generally indicated by reference numeral 21 3 The mixing device 21 3 is similar in many respects to the mixing devices of Figures 1 and 3 described above, like reference numerals refer to like components or features and emphasis will merely be placed on three important developments embodied in the device of Figure 4, without describing it in detail.
First, the conduit 21 2 by means of which drive gas under pressure is conducted to the device 21 3, enters the annular plenum 21 4 tangentially as opposed to radially as shown in Figure 2 for the device 1 3 This has the effect that the drive gas is rotated annularly, le it is swirled, within the plenum 21 4 which rotational component of flow is retained while flowing through the nozzle 21 5 and into the mixing chamber 21 6
The Applicant does not wish to be bound by theory, but a possible explanation of the advantage of the rotational flow component in the drive gas is that the drive gas has a longer residence time in the mixing chamber 21 6 while still maintaining high kinetic energy which enhances mixing
A second advantage is that the annular nozzle 21 5 is a converging nozzle thus accelerating the drive gas in the drive gas flow stream as it is directed into the mixing chamber This enhances the Bernoulli effect and enhances entrainment or inducement of the passive gas into the mixing chamber.
It is a further advantage that the nozzle 21 5 is annularly spaced inwardly of an outer periphery of the mixing chamber 21 6. Thus, passive gas is induced both radially outwardly of the nozzle 21 5 and inwardly of the nozzle 21 5, thus nearly doubling the interface between the drive gas and the passive gas (it is borne in mind that the diameter and thus also the circumference of the nozzle outlet 21 8 is smaller than those of the periphery of the mixing chamber 21 6 and thus of those which a nozzle at the periphery of the mixing chamber would have) .
With reference to Figure 5, a mixing device 31 3 is combined with a gas turbine motor 300 including a compressor 302 and having a filter arrangement 304 to filter inlet air.
Axially downstream of the filter arrangement 304, an inlet stream of filtered air, generally indicated by reference numeral 306, is conducted into the compressor 302.
The filter arrangement 304 filters dust grit and other undesirable particulate matter which are carried by means of a scavenge stream 308 away from the filter arrangement 304 and away from the gas turbine motor 300 via a conduit 31 2.1 .
In accordance with the invention, the mixing device 31 3 having a mixing chamber 31 6 is arranged such that high pressure air bled off from downstream of the compressor 302 via a conduit 31 2 is entered as a drive gas via an annular inlet nozzle 31 5 into the mixing chamber 31 6.
The scavenge stream 308 is communicated with a central nozzle having a nozzle opening 320 inwardly of the annular drive gas nozzle
31 5 The drive gas induces the scavenge flow stream 308 to flow into the mixing chamber 31 6, thus to be extracted from the filter arrangement 304.

Claims

1 A method of mixing gases, the method including introducing a drive gas in a high speed drive gas flow stream annularly, generally longitudinally into a mixing chamber at an inlet end of the mixing chamber; causing a passive gas to be entrained or induced generally longitudinally within the annular drive gas flow stream at said inlet end of the mixing chamber, and causing the drive gas and the passive gas to mix within the mixing chamber.
2 A method as claimed in Claim 1 in which causing said passive gas to be entrained or induced into said drive gas flow stream is from centrally within the annular drive gas flow stream.
3 A method as claimed in Claim 2 in which introducing said drive gas flow stream into the mixing chamber is at an annular position inwardly spaced from a periphery of the mixing chamber, the method including causing a passive gas to be entrained or induced also from outwardly of said annular drive gas flow stream at said inlet end of the mixing chamber.
4 A method as claimed in Claim 3 in which said passive gas caused to be entrained or introduced from within the annular drive gas flow stream and said passive gas caused to be entrained or introduced from outwardly of said annular drive gas flow stream, are the same passive gas from a common source.
5. A method as claimed in any one of the preceding claims, in which said passive gas is ambient air, the method including placing said inlet end of the mixing chamber in communication with the atmosphere.
6. A method as claimed in any one of the preceding claims, which includes directing said drive gas flow stream into the mixing chamber via an annular, longitudinally directed nozzle at or toward the periphery of the mixing chamber at said inlet end .
7. A method as claimed in Claim 6 in which said nozzle is a converging nozzle, the method including accelerating said drive gas flow stream when introducing it into the mixing chamber.
8. A method as claimed in any one of the preceding claims, which includes rotating said drive gas annularly to cause said drive gas flow stream introduced generally longitudinally into the mixing chamber to have also a rotational component of flow.
9 A method as claimed in any one of the preceding claims, in which said drive gas is hot exhaust gas from a combustion motor, said passive gas is cold ambient air, and mixing of the gases in the mixing chamber forms a cool mixture having a reduced infra-red signature compared to the hot exhaust gas.
1 0. A method as claimed in any one of Claim 1 to Claim 8 inclusive in which said drive gas is high pressure, high temperature air bled off downstream of a compressor of a gas turbine motor of an aircraft, in which said passive gas is cold, ambient air, and in which mixing of the gases in the mixing chamber produces a mixture appropriate for inhalation by humans, the method including introducing the mixture into a cabin of said aircraft.
1 1 A mixing device including a mixing chamber having an inlet end and an opposed exhaust end, an annular nozzle toward said inlet end directed longitudinally along the mixing chamber, the inlet nozzle having connection means for connection to a source of drive gas under pressure; an inlet opening annularly adjacent the annular nozzle, said inlet opening being in communication with a source of a passive gas to cause, in use, said passive gas to be entrained or induced into the mixing chamber.
1 2 A mixing device as claimed in Claim 1 1 in which said inlet opening is inwardly adjacent the annular nozzle.
1 3. A mixing device as claimed in Claim 1 1 in which said inlet opening is outwardly adjacent the annular nozzle.
14 A mixing device as claimed in Claim 1 1 in which said inlet opening is both inwardly adjacent and outwardly adjacent the annular nozzle.
1 5 A mixing device as claimed in any one of Claim 1 1 to Claim 1 4 inclusive in which said source of passive gas is the atmosphere and said passive gas is ambient air.
1 6 A mixing device as claimed in any one of Claim 1 1 to Claim 1 5 inclusive in which said nozzle is a converging nozzle to cause the drive gas to accelerate to be introduced into the mixing chamber at high speed
1 7 A mixing device as claimed in any one of Claim 1 1 to Claim 1 6 inclusive which includes an annular plenum upstream of said nozzle, the connection means for the nozzle being on the plenum for connection to the source of drive gas under pressure.
1 8 A mixing device as claimed in Claim 1 7 in which said connection means includes a nipple or conduit extending transversely of an axis of the plenum.
1 9 A mixing device as claimed in Claim 1 8 in which said nipple or conduit extends generally tangentially to said plenum, in use to guide said drive gas under pressure correspondingly generally tangentially into the plenum to cause rotation of said drive gas in the plenum and to cause said drive gas to be introduced into the mixing chamber in a generally longitudinal drive gas flow stream having a rotational component of flow.
20. A combination of a mixing device as claimed in any one of Claim 1 1 to Claim 1 9 inclusive and an aircraft having a combustion motor including an exhaust conduit for exhausting products of combustion, in which combination said combustion motor via said exhaust conduit is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to an outlet of said exhaust conduit, and in which combination said inlet opening is communicated with the atmosphere. 21 A combination as claimed in Claim 20 in which said mixing chamber extends longitudinally in the direction of flying of the aircraft, and in which said exhaust conduit extends transversely.
22 A combination of a mixing device as claimed in any one of Claim 1 1 to Claim 1 9 inclusive, and an aircraft having a gas turbine motor including a compressor for compressing ambient air prior to combustion, in which combination said compressor is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to said gas turbine motor to bleed off a small portion of compressed, high temperature air downstream of the compressor and upstream of a combustion chamber of the gas turbine motor, and in which combination said inlet opening is communicated with the atmosphere, said exhaust end of the mixing chamber being communicated with a cabin of the aircraft to supply the cabin with air appropriate for inhalation by humans
23 A combination of a mixing device as claimed in any one of Claim
1 1 to Claim 1 9 inclusive, and an aircraft having a gas turbine motor including a compressor for compressing ambient air prior to combustion, the aircraft including a filter arrangement in which, in use, a scavenge air flow stream laden with dust or other particles and a filtered air flow stream purged of dust and other particles to provide filtered inlet air for the gas turbine engine are generated, in which combination said compressor is said source of drive gas under pressure, said connection means of said inlet nozzle being connected to said gas turbine motor to bleed off a small portion of compressed, high temperature air downstream of the compressor and upstream of a combustion chamber of the gas turbine motor, and in which combination said inlet opening is communicated with said filter arrangement to collect said scavenge air flow to be entrained or induced into said drive gas flow stream.
PCT/IB2000/000767 1999-06-09 2000-06-08 Method and device for mixing gases WO2000074831A1 (en)

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ZA993879 1999-06-09
ZA99/3879 1999-06-09

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023039634A1 (en) * 2021-09-17 2023-03-23 Samuel Kang A turbine assisted venturi mixer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2678913C1 (en) * 2018-03-06 2019-02-04 Владимир Евгеньевич Иванов Multi-nozzle jet engine

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1491215A (en) * 1965-09-21 1967-08-11 Bertin & Cie Improvements to ejectors-mixers or tubes
US3441045A (en) * 1966-12-02 1969-04-29 Boeing Co Variable orifice nozzle mixing ejector
GB2123486A (en) * 1982-07-12 1984-02-01 Gen Electric Turbofan mixed flow exhaust system
EP0149574A2 (en) * 1984-01-13 1985-07-24 Compagnie De Raffinage Et De Distribution Total France Method for diluting a gas, or mixture of gases, with air before discharge to atmosphere
JPS6227030A (en) * 1985-07-26 1987-02-05 Reika Kogyo Kk Ejector device
EP0474524A1 (en) * 1990-07-27 1992-03-11 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process and device for mixing two gases
EP0888966A2 (en) * 1997-07-02 1999-01-07 Boeing North American, Inc. High efficiency environmental control systems and methods
FR2785643A1 (en) * 1998-11-05 2000-05-12 Snecma Heat screening for jet engines, has hollow bulb shaped body held in jet outlet nozzle by arms, which feed cooling fluid into body; fluid is then evacuated through wall openings and downstream neck.

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1491215A (en) * 1965-09-21 1967-08-11 Bertin & Cie Improvements to ejectors-mixers or tubes
US3441045A (en) * 1966-12-02 1969-04-29 Boeing Co Variable orifice nozzle mixing ejector
GB2123486A (en) * 1982-07-12 1984-02-01 Gen Electric Turbofan mixed flow exhaust system
EP0149574A2 (en) * 1984-01-13 1985-07-24 Compagnie De Raffinage Et De Distribution Total France Method for diluting a gas, or mixture of gases, with air before discharge to atmosphere
JPS6227030A (en) * 1985-07-26 1987-02-05 Reika Kogyo Kk Ejector device
EP0474524A1 (en) * 1990-07-27 1992-03-11 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process and device for mixing two gases
EP0888966A2 (en) * 1997-07-02 1999-01-07 Boeing North American, Inc. High efficiency environmental control systems and methods
FR2785643A1 (en) * 1998-11-05 2000-05-12 Snecma Heat screening for jet engines, has hollow bulb shaped body held in jet outlet nozzle by arms, which feed cooling fluid into body; fluid is then evacuated through wall openings and downstream neck.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 011, no. 202 (C - 432) 30 June 1987 (1987-06-30) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023039634A1 (en) * 2021-09-17 2023-03-23 Samuel Kang A turbine assisted venturi mixer

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