Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
  • F04F5/00—Jet pumps, i.e. devices in which flow is induced by pressure drop caused by velocity of another fluid flow
  • F04F5/44—Component parts, details, or accessories not provided for in, or of interest apart from, groups F04F5/02 - F04F5/42
  • F04F5/46—Arrangements of nozzles
  • F04F5/463—Arrangements of nozzles with provisions for mixing
• • 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
  • B01F23/20—Mixing gases with liquids
  • B01F23/29—Mixing systems, i.e. flow charts or diagrams
• • 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
  • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
• • 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
  • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
  • B01F25/3124—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow
  • B01F25/31243—Eductor or eductor-type venturi, i.e. the main flow being injected through the venturi with high speed in the form of a jet
• • 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
  • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
  • B01F25/3125—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characteristics of the Venturi parts
  • B01F25/31253—Discharge
  • B01F25/312533—Constructional characteristics of the diverging discharge conduit or barrel, e.g. with zones of changing conicity

Definitions

• the present invention relates to an ejector device for forming a pressurized mixture of liquid and gas.
• WO-Ol / 34285 describes such an ejector device comprising a suction chamber, a tube
• a nozzle injects a high velocity liquid into the suction chamber, which then sucks gas through an inlet.
• the cylindrical tube is located between the suction chamber and the diffuser, such
• Such an ejector device makes it possible to obtain compression ratios (see definition below) of the order of 4 to 8.
• 20 atm can be compressed to a pressure of 16 atm.
• the present invention aims to improve an ejector device of this type, in particular to optimize its energy efficiency and increase the compression rate.
• the invention relates to an ejector device for forming a pressurized mixture of liquid and gas, comprising a suction chamber and a diffuser, wherein the suction chamber comprises: an injection nozzle for producing a jet of liquid flowing in a longitudinal direction;
• the diffuser is connected to the outlet opening of the suction chamber and has along the longitudinal direction an increasing cross section from said outlet opening, the expanding section diffuser being located immediately after the opening outlet of the suction chamber, and wherein the diffuser (6) comprises at least a first conical portion having a first angle of between 0.1 and 7 degrees.
• the mixture of liquid and gas can be made at different axial positions inside the diffuser, and the ejector device then allows operation over a wide range of compression ratio.
• the first angle is preferably between 1.5 and 4 degrees;
• the diffuser further comprises a second conical portion continuously in the extension of the first portion in the longitudinal direction, said second portion having a second angle greater than the first angle;
• the second angle is between 5 and 15 degrees, and preferably of the order of 7 degrees;
• the diffuser further comprises a second portion continuously in the extension of the first portion in the longitudinal direction, said second portion having a convex profile shape;
• the second convex portion has a gradually increasing angle along the longitudinal direction from the first angle to an angle less than 15 degrees, and preferably of the order of 10 degrees;
• the diffuser is substantially coaxial with the injection nozzle and the outlet opening of the suction chamber;
• the ejector device is such that: the outlet opening, also called a neck, has a neck surface S 0 perpendicular to the longitudinal direction,
• the injection nozzle has a nozzle surface S 2 internally to the nozzle and perpendicular to the longitudinal direction, and
• a geometric ratio R is the ratio between the nozzle surface S2 and at the neck surface S c , said geometric ratio R being between 0.5 and 0.9;
• the ejector device is such that:
• the injection nozzle comprises an end in the longitudinal direction
• the outlet opening has a circular section with a neck diameter Dc
• the end is at a withdrawal distance x 2 from the outlet opening, said withdrawal distance x 2 being between one and five times the neck diameter Dc;
• the suction chamber comprises walls in the longitudinal direction extending radially in said suction chamber, so that the ga 2 flows into the suction chamber with a low turbulence flow, without rotation, the Axial velocity distribution is fairly homogeneous;
• the injection nozzle comprises means for channeling the liquid adapted to obtain in the nozzle after said channeling means, a liquid flow little turbulent, without rotation and whose axial velocity distribution is substantially homogeneous;
• the means for channeling the liquid in the nozzle are chosen from:
• a device having walls extending in the longitudinal direction and a device having walls extending in the longitudinal direction and said walls having a honeycomb shape
• a device comprising a wall in a direction substantially perpendicular to the longitudinal direction and comprising holes for distributing the liquid flow substantially uniformly in the cross section of the nozzle.
• the invention also relates to the use of an ejector device of the above type, in which:
• the suction pressure of the gas pi is measured at the gas inlet (3), the liquid supply pressure p 2 supplying the injection nozzle (5), the delivery pressure p 3 of the gas mixture and liquid downstream of the diffuser (6), and the absolute pressure of supply of liquid p 2 is adjusted to within twenty percent of an optimum pressure p 2 , O pt, such that: Thanks to these usage arrangements, the energy performance of the ejector device is optimized.
• the invention may for example be used in a gas compressor comprising an ejector device fed with a gas on the one hand and a liquid on the other hand, and a separator device adapted to receive a mixture of liquid and gas from the ejector device and extracting a gaseous component of this mixture, wherein the ejector device comprises a suction chamber and a diffuser, wherein the suction chamber comprises: an injection nozzle for producing a jet of liquid flowing according to a longitudinal direction;
• the diffuser is connected to the outlet opening of the suction chamber and has along the longitudinal direction an increasing cross section from said outlet opening, the expanding section diffuser being located immediately after the opening outlet of the suction chamber, and wherein the gas separator device has two outlets, one for the gas and the other for the liquid.
• the diffuser comprises at least a first conical portion having a first angle of between 0, 1 and 7 degrees;
• the separator device is a gravity separator;
• the separating device is a cyclonic separator;
• the gas compressor further comprises a pump adapted to suck the pressurized liquid at the separator device, and to supply with said liquid the injection nozzle of the ejector device.
• FIG. 1 is a diagrammatic view in longitudinal section of an ejector device according to the invention
• FIG. 2 is a graph, based on experimental results, showing the entrainment rate ⁇ e (see definition below) as a function of the compression ratio ⁇ c (see definition below) for different values of the pressure.
• FIG. 3 is a graph showing the theoretical efficiency of the ejector device (see definition below) of FIG. 1, for a compression ratio of the order of 4, as a function of a geometric ratio R for different training rate values
• FIG. 4 is a graph showing the efficiency of the ejector device of FIG. 1, as a function of a compression parameter ⁇ for different values of the parameter
• the driving pressure ⁇ (see definition below) is a schematic view of a gas compressor comprising the ejector device of FIG.
• the longitudinal direction mentioned in this description is understood to be the direction indicated by a mixed line X in FIG. 1, and corresponds to the direction of flow in the ejector device 1 between the upstream side situated to the left and the downstream side. located to the right in this figure.
• FIG. 1 represents a schematic view in longitudinal section of an ejector device 1 according to the invention.
• This ejector device extends along the longitudinal axis X and comprises along this axis:
• a suction chamber 2 adapted to suck a gas by injecting a jet of liquid at high speed into said suction chamber 2,
• the suction chamber 2 comprises: a lateral inlet opening 3 through which the gas is fed,
• an injection nozzle terminating in a cylindrical tube substantially coaxial with the longitudinal axis X and opening into said suction chamber, and through which a liquid is injected at a high speed into said suction chamber, and
• the outlet opening 4 therefore forms at the outlet of the suction chamber 2 a shrinkage also called collar.
• a first upstream conduit 3a supplies gas the inlet opening 3 of the suction chamber 2, to one suction pressure p x with volume flow Qi.
• a second upstream pipe 5a feeds the injection nozzle 5 with liquid at a supply pressure p 2 with a volume flow rate Q 2 .
• the nozzle 5 has an end 5b in the suction chamber 2, of internal diameter D 2 and having a nozzle surface S 2 , perpendicularly to the longitudinal axis X. This end 5b is placed at a withdrawal distance X 2 from the outlet opening 4 of the suction chamber 2.
• the internal diameter D 2 of the end 5b is possibly less than one internal diameter of the nozzle 5, such that said nozzle has at its end 5b a contracted section.
• the injection nozzle 5 optionally comprises liquid channeling means adapted to obtain in the nozzle after said channeling means, a liquid flow little turbulent, without rotation and whose axial velocity distribution is substantially homogeneous, that is, that is, whose axial velocity distribution in a cross-section of the nozzle is substantially constant.
• the jet of liquid produced by the nozzle 5 in the suction chamber 2 then remains substantially cylindrical to the outlet opening 4 of said chamber.
• the liquid jet diverges little in this chamber and does not begin to mix with the gas before the diffuser 6.
• having a jet of liquid diverges helps to form a mixture of liquid and water. gas.
• this arrangement makes it possible to obtain a better mixture of liquid and gas in the diffuser 6 and a better compression ratio of this mixture.
• nozzle 5 may for example be a device having walls extending in the longitudinal direction X, or a device having walls extending in the direction longitudinal X and said walls having a honeycomb shape, or a device comprising a wall in a direction substantially perpendicular to the longitudinal direction X and comprising holes for distributing the liquid flow substantially uniformly in the cross section of the nozzle, or a combination of these devices in the nozzle 5 and arranged one after the other along the longitudinal direction X.
• the channeling means can then be placed in the nozzle at a short distance from its end 5b, for example at a distance of between 10 and 30 times the internal diameter D 2 of the nozzle 5, and preferably equal to 20 times this diameter. .
• the diffuser 6 is mounted in the extension of the outlet opening 4 of the suction chamber.
• This diffuser 6 has along the longitudinal direction X an increasing cross-section from said outlet opening 4.
• This diffuser 6 is for example of conical shape, flaring in the direction of the flow, and is also substantially coaxial to the longitudinal axis X. It therefore has an upstream diameter substantially equal to the diameter D c of the outlet opening 4 of the suction chamber 2, and a downstream diameter D 3 greater than the upstream diameter D c .
• the diffuser 6 forms a cone having an angle CXa-
• the angle (Xd is defined as the total opening angle of the cone, and has a low value, at least in a first part of the diffuser 6.
• a downstream pipe 6a outputs the mixture of liquid and gas at the discharge pressure p 3 .
• the ejector device 1 of the invention has a diffuser 6 located immediately at the outlet of the suction chamber 2, that is to say without interposition of a cylindrical tube for mixing liquid and gas, so that the mixture occurs directly in the diffuser 6.
• the driving pressure parameter% is defined as the ratio between the liquid supply pressure p 2 supplying the injection nozzle 5 and the gas suction pressure pi:
• the ejector device 1 operates as follows.
• the suction chamber 2 optionally comprises from said distance from the longitudinal axis X radially and longitudinally extending walls, so that the liquid jet does not come into contact with said walls and that the gas contained in this suction chamber 2 is driven with a low turbulent flow, without rotation and whose axial velocity distribution is substantially homogeneous towards the outlet opening 4 of the suction chamber 2.
• the flow comprises along the X axis, a first, a second and a third zone.
• the first zone of the flow the two coaxial phases flow relatively independently.
• the mixing zone the flow changes its structure rather suddenly and becomes a mixture of the liquid and the gas, which is more and more homogeneous. This change in the structure of the flow is accompanied by a fairly sudden slowing down of the liquid phase and an increase in pressure.
• the third flow zone the two phases flow in the form of a finely mixed emulsion. In this third zone, the flow gradually slows under the effect of the section increase of the diffuser. The kinetic energy of the mixture is then converted into pressure energy.
• first, second and third zones of the flow are not separated by clear and sharp transitions, the phenomena being continuous.
• these zones of the flow can move longitudinally in the diffuser 6, in particular by the effect of variations in the discharge pressure p 3 downstream of the diffuser 6.
• the operation of the ejector device is undisturbed, which shows that such a device is stable and tolerant of variations in operating parameters.
• the amount of movement of the liquid jet at the inlet of the diffuser 6 is converted into pressure forces applied on both sides of the mixing zone. If one makes an analogy with the compressible flows, this conversion can be seen as a shock. If one makes an analogy with the free surface flows, this conversion can be seen as a hydraulic jump.
• the diffuser 6 of conical shape has a low angle (X d , but not zero.
• a conical diffuser 6 with a higher angle OCa, for example greater than 10 degrees, does not cause a hydraulic shock as effective and does not allow achieve such high compression rates.
• the diffuser 6 comprises along the axis X a first conical portion with a first angle OCa / and then a second conical portion with a second angle. The second portion is continuously in the extension of the first portion. The second angle is greater than the first angle.
• the second angle may be between 5 and 15 degrees, and preferably of the order of 7.
• the first portion is intended to accommodate the mixing zone, which must operate under a slight angle of divergence in order to maximize the com rate
• the second portion provides the final pressure recovery by conversion of the kinetic energy of the mixture. This energy conversion can take place at a higher angle of divergence, for example of the order of 10 °, without generating a significant loss of load.
• a high compression ratio ⁇ c is obtained at the same time by the first portion with a small divergence angle and a total length of the shortened diffuser 6.
• the diffuser 6 has a flared shape with a first portion of conical shape with a small first angle, then in continuity a shape having a convex profile.
• the second convex portion has an incrementally increasing angle along the longitudinal direction X from the first angle to an angle, for example less than 15 degrees, and preferably of the order of 10 degrees.
• the overall length of the diffuser 6 can thus be further shortened without affecting the compression ratio.
• the diffuser 6 has a flared shape with a shape having a convex profile, said convex profile having a gradually increasing angle along the longitudinal direction X from a first angle OCa to an angle , for example less than 15 degrees, and preferably of the order of 10 degrees.
• the overall length of the diffuser 6 can thus be further shortened.
• the first angle ⁇ a of the preceding variants preferably has a value in the range of 0.1 ° to 7 °, as indicated above.
• the efficiency ⁇ of the ejector device 1 is the ratio between the compression power P c in the ejector device 1 and the hydraulic power P h provided.
• Ph Q 2 (P 2 -Ps) where the following yield ⁇ : that one can write according to the adimensional parameters defined previously: ln ( ⁇ c )
• the efficiency ⁇ of an ejector device 1 can therefore be measured on experimental devices, or be calculated by a mathematical model of hydraulic flow.
• the dimensionless geometric ratio R is also defined as being the ratio of the nozzle area S 2 to the neck area S c :
• the efficiency ⁇ is linked to this geometric ratio R of the ejector device 1.
• the efficiency ⁇ is maximum for a geometric ratio R between 0.5 and 0 , 9, or more precisely between 0.6 and 0.8. This trend has been confirmed by experimental results.
• a first advantage of this compression parameter ⁇ is that it can be calculated only with the pressure values, measurable on an experimental ejector device.
• the efficiency ⁇ is related to the value of this compression parameter ⁇ of the ejector device 1.
• the curves of FIG. 4 show this dependence for several values of the driving pressure parameter ⁇ .
• yield ⁇ is then maximum for a compression parameter ⁇ in the range of 0.4 to 0.6, or preferably equal to about 0.5.
• a second advantage of this compression parameter ⁇ is that, inversely, it can make it possible to determine the liquid supply pressure p 2 adapted to obtain the optimum efficiency ⁇ ot of the ejector device 1. Indeed, the preceding interval for the compression parameter ⁇ makes it possible to determine that the liquid supply pressure p 2 must be in the following range:
• the ejector device 1 can then be used in a gas compressor 10 as shown in FIG. 5.
• This gas compressor 10 comprises: a gas inlet 11 at low pressure,
• the hydraulic circuit comprises in series: an ejector device 1 supplied on the one hand with a low-pressure gas, coming from the gas inlet 11 and on the other hand with a high-pressure liquid; said ejector device 1 supplying a mixture of gas and liquid at intermediate pressure, - a separating device 13 supplied with a mixture of gas and liquid by the ejector device 1 and supplying on the one hand a gas component at the gas outlet 12 at intermediate pressure and a liquid, at the same intermediate pressure, at a return circuit 14, - a heat exchanger 15 in the return circuit 14 adapted to maintain the temperature of the hydraulic circuit at an adequate level,
• a pump 16 fed by the liquid of the return circuit 14 and supplying a liquid of higher pressure to a supply circuit 17.
• the supply circuit 17 then supplies the ejector device 1 of the gas compressor 10 with liquid.
• the separator device 13 is either a gravity separator or a cyclonic separator.
• a bypass circuit 14a bypasses
• the heat exchanger 15 of the return circuit 14 and comprises a valve 14b.
• This branch circuit 14a is adapted to adjust the temperature of the hydraulic circuit.
• the heat exchanger 15 is also fed with a cold fluid, for example water, by a cooling circuit 15a and a pump 15b.
• a cold fluid for example water
• the gas compressor 10 operates as follows.
• the ejector device 1 mixes the gas with a liquid injected at high speed, and compresses this mixture of gas and liquid at a high pressure.
• the mixture is separated in the separator device 13, which then supplies at the gas outlet 12 a high pressure gas, and the return circuit 14 also a high pressure liquid.
• the heat exchanger 15 makes it possible to extract heat from the liquid.
• the pump 16 increases the pressure of the liquid before supplying the supply circuit 17 and the ejector device 1.
• the ejector device 1 comprises an injection nozzle adapted to inject at high speed said liquid into its suction chamber.
• the injection nozzle of the ejector device 1 performs a relaxation of the liquid (transformation of the pressure energy of the liquid into kinetic energy).
• the diffuser of the ejection device 1 performs mixing and compression of the mixture.
• the pump 16 completes the compression of the liquid to reach the inlet supply pressure of the nozzle of the ejector device.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Jet Pumps And Other Pumps (AREA)
• Nozzles (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=41343301

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (10)

Citations (11)

Family Cites Families (12)

• 2009
  • 2009-04-09 FR FR0952369A patent/FR2944218B1/fr not_active Expired - Fee Related
• 2010
  • 2010-04-02 WO PCT/FR2010/050637 patent/WO2010116076A1/fr active Application Filing
  • 2010-04-02 EP EP10723191.2A patent/EP2416874B1/de not_active Not-in-force
  • 2010-04-02 US US13/263,681 patent/US20120034106A1/en not_active Abandoned
  • 2010-04-08 AR ARP100101192A patent/AR076244A1/es active IP Right Grant

Patent Citations (11)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events