EP0781929B1 - Device for pumping or compressing a multi-phase fluid comprising tandem blading - Google Patents

Description

The present invention relates to a fluid compression device multiphase which, before being compressed and under pressure conditions and of temperature considered, consist of a mixture in particular of a liquid phase and a gaseous phase not dissolved in the liquid, this liquid may or may not be saturated with gas.

The compression device or compression cell according to the invention is particularly well suited for pumping a multiphase fluid, for example, but not exclusively, a multiphase petroleum effluent composed of a mixture of water, oil and gas, and possibly particles solid. Pumping such an effluent poses problems all the more difficult to solve that in the thermodynamic conditions where is found the multiphase fluid before pumping, the value of the volumetric ratio of the gas to liquid is greater.

Recall that the volumetric ratio of gas and liquid, called thereafter abbreviated "volumetric report" or GLR from English "Gas Liquid Ratio ", is defined as the ratio of the volume of fluid in gaseous state to volume of fluid in liquid state, the value of this ratio being in particular function of the thermodynamic conditions of the multiphase fluid.

Whatever the design of the pumps used (alternative pumps, rotary pumps or trumpet pumps), good results are obtained when the value of the volumetric ratio of the fluid is very low or even zero, because the fluid then behaves like a liquid monophasic fluid. These materials are still usable when their operating conditions do not do not reveal phenomena likely to allow the vaporization of a significant part of the gas dissolved in the liquid, or when the value of the volumetric ratio at the input of the pump is at most equal to 0.2. Experience shows that beyond this value, the efficiency of these devices decreases very quickly.

To improve the functioning of existing devices, a solution consists in separating the liquid phase from the gas phase before pumping, and process the phases separately, in separate compression circuits respectively adapted to communicate a compression value to a essentially liquid phase or an essentially gaseous phase. Setting using separate circuits is not always possible and often leads to larger, more expensive and more complex pumping systems.

That’s why we tried to develop pumping devices adapted, not only to increase the total energy of the multiphase fluid, but capable of producing a multiphase fluid whose value of the ratio volumetric output of the pumping device is less than the value it has before pumping.

The prior art describes different blading profiles making it possible to obtain this result, in particular the applicant's patents FR-2,157,437, FR-2,333,139, FR-2,471,501 and FR-2,665,224, which specify blade profiles or even a geometry chosen for the fluid passage section delimited by two successive blasting. In all cases, these profiles relate to blading simple, that is to say comprising only one piece unlike Blades, called "tandem blading", which include for the same group, at minus two blades.

The performance of multiphase fluid pumping including so-called "simple" blades can be improved.

Thus, the prior art described, for example in the article "Optimization for Rotor Blades of Tandem Design for Axial Flow Compressors ", published in journal of Engineering for Power, Vol. 102, page 369 in April 1980, the use compression devices comprising blades having tandem profiles.

However, the teaching of this prior art concerns only the compression of monophasic fluid, i.e. which, at the input of the device compression, essentially consist of a single phase, i.e. liquid or gas. The geometric characteristics of type blades tandem described in this document are particularly well suited to the compression of a monophasic fluid whose behavior in compression cannot be compared to the behavior of a fluid with several phases, for example fluids having at least one liquid phase and at least one gas phase, and therefore which are not suitable for pumping of a multiphase fluid.

It has been discovered, and this is one of the objects of the present invention, that the pumping of multiphase fluid can be improved by using blades tandem or "tandem blading" type with a geometric configuration adapted to compress a multiphase fluid comprising at least one liquid phase and at least one vapor or gas phase, the proportions of these two phases that can vary over time.

As a reminder and throughout the description, we define the skeleton of a dawn like the surface at all equidistant from the faces intrado and extrado of this dawn. So when we consider the intersection of a vane with a current surface of the fluid flow around this dawn, we can describe a dawn profile using coordinates of the camber line and the law of thickness distribution dawn along this line.

• A_ij : désigne une aube ayant le numéro i dans le groupe d'aubes j,
• a_ij : désigne le bord d'attaque d'une aube A_ij,
• f_ij : le bord de fuite d'une aube A_ij,
• G_j : se réfère au groupe d'aubes,
• C_Tj : corde totale d'un groupe d'aubes qui correspond à la corde définie à partir d'une pale ayant un profil équivalent au profil déterminé à partir de l'ensemble des aubes,
• C_Fj : corde de la première aube d'un groupe d'aubes,
• C_Rj : corde de la seconde aube d'un groupe d'aubes, pour des groupes d'aubes comportant deux aubes, mais qui pourrait sans sortir du cadre de l'invention être étendue à un nombre supérieur à 2,
• h le décalage tangentiel qui correspond à la distance (f_ij, a_ij) projetée sur la direction périphérique (perpendiculaire à l'axe de rotation),
• α angle qui est défini sur des cylindres sensiblement coaxiaux de rayons constants dont l'axe est confondu avec l'axe de rotation de la machine. Sur ces surfaces, α est l'angle que fait la direction périphérique (perpendiculaire à l'axe de rotation) et la tangente en un point quelconque à la courbe tracée par le squelette tel que défini précédemment.

In the following description, the following references will be used:

• A _ij : designates a blade having the number i in the group of blades j,
• a _ij : designates the leading edge of a blade A _ij ,
• f _ij : the trailing edge of a blade A _ij ,
• G _j : refers to the group of blades,
• C _Tj : total chord of a group of blades which corresponds to the chord defined from a blade having a profile equivalent to the profile determined from all the blades,
• C _Fj : chord of the first blade of a group of blades,
• C _Rj : chord of the second blade of a group of blades, for groups of blades comprising two blades, but which could without departing from the scope of the invention be extended to a number greater than 2,
• h the tangential offset which corresponds to the distance (f _ij , a _ij ) projected onto the peripheral direction (perpendicular to the axis of rotation),
• α angle which is defined on substantially coaxial cylinders of constant radii whose axis coincides with the axis of rotation of the machine. On these surfaces, α is the angle made by the peripheral direction (perpendicular to the axis of rotation) and the tangent at any point on the curve drawn by the skeleton as defined above.

To obtain the aforementioned improvement, the device according to the present invention uses tandem blades, comprising blades formed by a or more profiles or blades.

For example, when the blade or the group of blades G _j has two blades A _1j and A _2j , the first blade, called for example the main blade, is the one which sees the fluid in flow, or the particle of fluid, the first, and the second blade is called, for example, auxiliary blade.

The particular geometric characteristics of each of these blades, as well as their arrangement with respect to each other, make it possible to optimize the compression of a multiphase fluid and remixing at least part of the liquid phase coming from a first group of blades with at least one part of the gas phase from the previous group of blades. We thus promotes the meeting of at least part of the gas phase which flows near the upper surface and at least part of the phase liquid which circulates on the side of the lower surface.

The different blades forming a blade can be found completely separate from each other or derive from a dawn in which are arranged orifices, or passage lights, each of the parts separated by these orifices which can be assimilated to a blade.

• paramètre 1 : le décalage tangentiel h rapporté au pas t, exprimé sous la forme du rapport h/t, où t est le pas correspondant à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux deuxième aubes de chacun des groupes d'aubes, la valeur du paramètre 1 est compris dans l'intervalle de 0,95 à 1,05,
• paramètre 2 : le rapport du recouvrement axial r_j et de la corde totale CTj correspondant à un groupe d'aubes qui est compris dans l'intervalle de valeurs de 0,0, à 0,15,
• paramètre 3 : le rapport de corde R_Cj = (C_Fj / C_Rj) défini pour un groupe d'aubage par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la deuxième aube C_Rj pour un des groupes d'aubes compris entre 0,5 et 1,5,
• paramètre 4 : le rapport de cambrure Φ_j défini par la valeur de la cambrure Φ_Fj de la première aube à la valeur de la cambrure Φ_Rj de la deuxième aube d'un même groupe d'aube, compris entre 0,5 et 1.

Thus, the present invention relates to a device for compressing or pumping a multiphase fluid comprising at least one liquid phase and at least one gaseous phase, the device comprising at least one hollow casing (1) having at least one inlet orifice (2) and at least one discharge orifice (3) for said fluid, at least one rotor which can rotate inside this casing along an axis of rotation Ox, an impeller comprising two groups of blades each comprising a first blade and a second blade, the impeller being integral with the rotor, the blades of the impeller having a leading edge a _ij and a trailing edge f _ij , the angle α formed by the tangent to the curve of the skeleton, said angle being counted from the leading edge aij of at least one of said first and / or second blade relative to the peripheral or tangential direction of the device is between 0 and 45 °, the device comprising a rectifier comprising two groups of '' blades comprising c each a third and a fourth blade, characterized in that the characteristics and the positioning of the impeller blades are determined as a function of at least one parameter chosen from the following four parameters:

• parameter 1: the tangential offset h relative to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades of each of the groups blades, the value of parameter 1 is in the range from 0.95 to 1.05,
• parameter 2: the ratio of the axial overlap r _j and the total chord CTj corresponding to a group of blades which is included in the range of values from 0.0, to 0.15,
• parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second dawn C _Rj for one of the groups of blades between 0.5 and 1.5,
• parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first blade to the value of the camber Φ _Rj of the second blade of the same group of blades, between 0.5 and 1 .

As a reminder and in the following description, we define the skeleton a dawn like the surface at any equivalent point of the lower surface and extrado of this dawn. When we consider the intersection of a dawn with a current surface of the flow around this dawn we can describe a blade profile using the geometric coordinates of the line of curvature and the law of distribution of the blade thickness along this line.

The present invention also relates to a device comprising for example at least one impeller comprising two blades or group of blades G ₁ , G2 each comprising a first blade A _1j and a second blade A _2j .

• paramètre 1 : le décalage tangentiel h rapporté au pas t, exprimé sous la forme du rapport h/t, où t est le pas correspondant à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux secondes aubes A₂₁ et A₂₂ de chacun des groupes d'aubes G₁ et G₂, la valeur du paramètre 1 est compris dans l'intervalle [0,95 1,05],
• paramètre 2 : le rapport du recouvrement axial r_j et de la corde totale C_Tj correspondant à un groupe d'aubes G_j qui est compris dans l'intervalle de valeurs [0,0; 0,15],
• paramètre 3 : le rapport de corde R_Cj = (C_Fj / C_Rj) défini pour un groupe d'aubage G_j par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj pour un des groupes d'aubage compris entre [0,5 1,5],
• paramètre 4 : le rapport de cambrure Φ_j défini par la valeur de la cambrure Φ_Fj de la première aube à la valeur de la cambrure Φ_Rj de la seconde aube d'un même groupe d'aubage, compris entre [0,5 ; 1].

It is characterized in that the geometrical characteristics of the first and / or of the second blade of each of the groups of blades Gj and the positioning of the different groups of blades with respect to each other are determined as a function of '' at least one parameter chosen from the following four parameters:

• parameter 1: the tangential offset h relative to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and A ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of the parameter 1 is included in the interval [0.95 1.05],
• parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [0,0; 0.15]
• parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group G _j by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second vane C _Rj for one of the vane groups between [0.5 1.5],
• parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first blade to the value of the camber Φ _Rj of the second blade of the same blade group, between [0.5; 1].

• paramètre 1 : le décalage tangentiel h rapporté au pas t, exprimé sous la forme du rapport h/t, où t est le pas correspondant à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux secondes aubes A₂₁ et A₂₂ de chacun des groupes d'aubes G₁ et G₂, la valeur du paramètre 1 est compris dans l'intervalle [0,60 ; 0,80],
• paramètre 2 : le rapport du recouvrement axial r_j et de la corde totale C_Tj correspondant à un groupe d'aubes G_j qui est compris dans l'intervalle de valeurs [-0,01 ; 0,05],
• paramètre 3 : le rapport de corde R_Cj = (C_Fj / C_Rj) défini pour un groupe d'aubage Gj par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj pour un des groupes d'aubage compris entre [0,5 ; 1,5],
• paramètre 4 : le rapport de cambrure Φ_j défini par la valeur de la cambrure Φ_Fj de la première aube à la valeur de la cambrure Φ_Rj de la seconde aube d'un même groupe d'aubage, compris entre [0,10 ; 1].

The device comprises at least one rectifier comprising two blades or group of blades G ₁ , G ₂ each comprising a first blade A _1j and a second blade A _2j . It is characterized in that the geometric characteristics of the first and / or of the second blade of each of the groups of blades G _j and the positioning of the different groups of blades with respect to each other are determined as a function at least one parameter chosen from the following four parameters:

• parameter 1: the tangential offset h related to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and A ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of the parameter 1 is included in the interval [0.60; 0.80]
• parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [-0.01; 0.05]
• parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group Gj by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second dawn C _Rj for one of the blading groups between [0.5; 1.5]
• parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first vane to the value of the camber Φ _Rj of the second vane of the same blade group, between [0.10; 1].

The device comprises for example a rectifier and / or an impeller comprising at least two groups of blades G ₁ , G ₂ each comprising a first blade (A ₁₁ , A ₁₂ ) and a second blade (A ₂₁ , A ₂₂ ), the geometric characteristics of said first and second blades of each of the groups of blades and the positioning of the different groups of blades relative to one another are for example determined as a function of three of the parameters given in claims 2 and / or 3, parameter 1, parameter 2 and parameter 3, each of these parameters belonging to the intervals cited above.

The geometric characteristics of at least one impeller and / or at least one rectifier of the compression device are for example specified using the fourth parameter, the value of the camber ratio Φ _j being chosen in combination with the three values of the parameters of claims 2 and / or 3.

The ratio of maximum thicknesses of the first and second blading e1 / e2 is for example between 0.5 and 1, for an impeller and / or a rectifier.

The thickness e1 of the first blade is between 2 and 10 mm and / or the thickness e2 of the second blade is between 2 and 20 mm.

A dawn is for example linked to a previous dawn and / or a dawn next using a mechanical element.

The device comprises for example at least one rectifier and at least an impeller, the impeller is for example placed before the impeller when we consider the direction of fluid flow.

The device comprises for example at least one impeller and at least two rectifiers, the impeller being for example disposed between the two rectifiers.

The invention also relates to a compression or pumping a multiphase fluid comprising at least one gaseous phase and at least one liquid phase, the device comprising a hollow casing having a inlet port and an outlet port for said multiphase fluid, at at least one rotor which can rotate inside said casing along an axis of Ox rotation, said rotor consisting of a hub and at least one blade integral with this hub, said blade comprising a first face or upper surfaces and a second face designated lower surface.

The device for compressing or pumping a multiphase fluid is characterized in that said blade is provided on at least part of its length of one or more openings allowing communication the two said lower and upper surfaces, in order to promote the encounter at least part of the gaseous phase flowing near the upper surface and at least part of the liquid phase flowing from the side of the lower surface.

The invention also relates to a multiphase pump intended for example with the pumping of multiphase petroleum type effluents. She is characterized in that it comprises at least one impeller and at least one rectifier which has one of the geometric characteristics for example previously mentioned.

It also applies to the definition of a multiphase pump intended pumping multiphase petroleum effluent, comprising for example a liquid phase, a gas phase and possibly a solid phase in the form of particles.

• elle permet de minimiser la séparation des phases liquide et gaz contenues dans l'effluent en favorisant au moins en partie leur remélange de phases,
• les pertes d'énergie hydraulique sont minimisées car :
  • l'aubage est mieux adapté à l'incidence de l'écoulement entrant dans le dispositif de compression,
  • le taux de décélération du fluide, élevé dans le cas de cambrures d'aubage fortes et ayant notamment pour conséquence d'augmenter les pertes hydrauliques et les risques de décollement de l'écoulement, s'en trouve minimisé, et
• au niveau du stator, la structure tandem des pales améliore le guidage du fluide et permet ainsi d'égaliser les vitesses des filets fluides dans la section de sortie.

Compared to devices comprising so-called "simple" blades, the tandem-type structure applied in particular to the field of pumping multiphase fluid, such as a petroleum effluent, in an optimized configuration defined above, gives the compression device the following advantages:

• it makes it possible to minimize the separation of the liquid and gas phases contained in the effluent by at least partially promoting their remixing of phases,
• hydraulic energy losses are minimized because:
  • the blading is better adapted to the incidence of the flow entering the compression device,
  • the rate of deceleration of the fluid, high in the case of strong vane camber and having in particular the consequence of increasing the hydraulic losses and the risks of separation of the flow, is thereby minimized, and
• at the level of the stator, the tandem structure of the blades improves the guidance of the fluid and thus makes it possible to equalize the speeds of the fluid threads in the outlet section.

• les figures 1 et 1A représentent schématiquement et en coupe axiale, un mode particulier de réalisation du dispositif selon l'invention pour le pompage, d'un effluent polyphasique,
• la figure 2 montre un impulseur ou roue mobile, vu en perspective,
• la figure 3 est une figure développée de la trace résultant de l'intersection des pales avec une surface cylindrique de rayon fixe, montrant les paramètres de définition d'une géométrie aubages tandem selon l'invention,
• la figure 4 schématise le mélange des flux de la phase gazeuse et de la phase liquide
• la figure 5 schématise un exemple de dispositif selon l'invention pour lequel les différents groupes d'aubes sont reliées par un moyen mécanique, et
• la figure 6 est un exemple de réalisation simpliste d'aubages selon l'invention pourvus de lumières permettant d'optimiser le mélange des phases.

Other advantages and characteristics of the invention will appear better on reading the description given below by way of exemplary embodiments, in the context of in no way limiting applications, in the compression or pumping of a multiphase effluent of petroleum type, comprising at least one liquid phase, one gaseous phase and possibly a solid phase, with reference to the appended drawings where:

• FIGS. 1 and 1A show schematically and in axial section, a particular embodiment of the device according to the invention for pumping, a multiphase effluent,
• FIG. 2 shows a moving impeller or wheel, seen in perspective,
• FIG. 3 is a developed figure of the trace resulting from the intersection of the blades with a cylindrical surface of fixed radius, showing the parameters for defining a tandem blade geometry according to the invention,
• Figure 4 shows schematically the mixture of gas phase and liquid phase flows
• FIG. 5 shows diagrammatically an example of a device according to the invention for which the different groups of blades are connected by mechanical means, and
• Figure 6 is a simplistic embodiment of blades according to the invention provided with lights to optimize the mixing of phases.

In what follows, we will designate under the word "fluid", a fluid multiphase including in particular a liquid phase and a gas phase, and possibly a solid phase which can be in the form of solid particles for example sand or viscous particles such as hydrate agglomerates. The liquid phase can in particular consist of liquids of different natures, just as the gas phase can be made up of gases of different types.

The fluid has phases of different natures inside and outside. the exterior of the compression device, unlike fluids monophasics which can undergo transformations inside the device.

Figures 1 and 1A schematically show in axial section a particular, non-limiting embodiment of the device according to the invention intended for pumping a multiphase petroleum effluent.

The pumping device comprises a hollow casing 1, which is by cylindrical example to be easily introduced into a well, for non-limiting applications of the device according to the invention relating to pumping effluent in a production well. The casing 1 is provided with at least one orifice 2 for admitting the multiphase fluid and at least one orifice discharge 3, which communicates with the flow circuit of the pumped fluid. This circuit is shown diagrammatically by a pipe or pipe 4 at the end of which the housing 1 is fixed by any suitable means known to those skilled in the art loom for example a thread referenced 5 in the figure.

In the example illustrated in FIG. 1A, the intake port 2 is present in the form of lights made in the wall of the casing 1, and the pumping device comprises at these orifices a deflector 14 integral with the casing 1 to deflect the fluid after it enters the casing and it print a speed having a substantially axial direction, that is to say substantially parallel to the axis of rotation of the pump.

Inside the casing 1 is placed a rotor comprising a shaft 6 rotated by motor means 7 (Figure 1), such as for example, but not exclusively, an electric motor, and possibly a transmission, shown schematically at 8 (Figure 1) allowing in particular to adapt the rotational speed of the motor shaft at the rotational speed at which be trained tree 6.

The shaft 6 is for example held in position by at least two separate bearings 9 and 10, for example described in the applicant's patent FR-2471501.

The bearing 10 is made integral with the casing 1 by radial arms 11, of so that the spaces between these radial arms allow the fluid to flow in the direction indicated by the arrow F.

Details concerning the mounting of bearings 9 and 10 are given explicitly in patent FR 2,471,501, in particular the assemblies for get the seal between the different parts of the device and are further sufficiently known to those skilled in the art not to be described further in detail below.

Between the inlet 2 and outlet 3 ports of the pumping and inside the casing 1, is placed at least one element or stage adapted to increase the total energy of the fluid.

In Figure 1, there are shown three elements having the function to increase the energy of the fluid, referenced 17, 18 and 19. This number is not limiting and depends on the increase in pressure which it is desired to obtain. These elements are hereinafter called impellers.

These elements described below in detail in Figure 3 are integral with the shaft 6 on which they are, for example, force fitted, the spacing between the elements being ensured by spacers 20 to 23.

Preferably, the device also includes one or more elements rectifiers. For example, a rectifier (24, 25, 26) is placed at the outlet of each pressurizing element (17, 18, 19), each rectifier being secured to housing 1, for example, by means of fixing screws 27.

The presence of rectifiers is not necessary for the implementation of the device according to the invention. Nevertheless, it offers a significant advantage because it allows to guide the fluid or effluent through the different stages of the compression device.

It is understood that the clearances between the pressurizing elements and the casing and the clearances between the pressurizing elements and the rectifiers are reduced in a manner known to those skilled in the art to their minimum value compatible with the operation of the pump.

Figure 2 shows, in perspective view, a non-limiting embodiment of a pressurizing element or impeller stage essentially comprising a hub 28 integral with the shaft 6 which, during the operation of the device, is rotated in the direction indicated by the arrow R . This hub 28 comprises at least one blade 30 composed of two blades 30a and 30b, hereinafter called first blade or main blade and second blade or auxiliary blade, whose geometric characteristics and positioning relative to each other are given in connection with FIG. 3. The number of blades 29, 30 is in no way limiting and given by way of example only. In general, this number is chosen to facilitate the static and dynamic balancing of the rotor. The height of the blades is such that the shape which they define during their rotation is complementary to the bore which, in this embodiment, is cylindrical.

The effective profile of a tandem blade or a group of blades corresponding to the profile that dawn would have if it were made up of a single part, may be substantially identical to one of the profiles described in the FR-2,157,437, FR-2,333,139, FR-2,471,501 and FR-2,665,224 of the applicant, the latter defining the profile of a blade from the section variation of an orthoradial canal defined by two successive blades. The profile of a blade tandem comprising a first blade 30a and a second blade 30b can effect be assimilated to an effective profile taking into account the profiles of each of the blades. It is also possible to define an orthoradial channel as the channel delimited by two effective blades or group of blades.

Likewise, each blade of a tandem blade can be chosen according to one profiles described in these patents.

The number of tandem blades, i.e. groups of blades arranged in tandem with each other, is always preferably greater than 2.

Without departing from the scope of the present invention, this number of blades can be between 3 and 8, and preferably between 4 and 6, in particular for impellers with a large outer diameter of the blades, understood by example between 200 and 400mm.

To ensure and optimize the compression of a multiphase fluid, the blades forming a blade or a group of blades and the arrangement of the blades and / or blades relative to each other inside the device compression have geometrical characteristics determined, by example using at least one of the parameters given in FIG. 3.

In the example described in FIG. 3, each group of blades G _j comprises, for example two blades A _1j and A _2j arranged one after the other, but could without departing from the scope of the invention be extended to groups of blades with a number of blades greater than 2.

The groups of blades are designated in FIG. 3, respectively by G ₁ and G ₂ . Each of the groups includes a first dawn A _1j or main dawn and a second dawn A _2j or auxiliary dawn.

A representation to describe a blade in a simple way, is to define its geometric layout on the developed surface of the envelope cylindrical to the outside radius.

In FIG. 3, the axis of rotation is represented by the line m, and the line p corresponds to the peripheral or tangential direction of the compression device. The arrow E corresponds to the direction of flow of the multiphase fluid entering the compression device.

Generally, a blade A _ij has a leading edge referenced in the figure "a _ij " and a trailing edge "f _ij ", where i is the number of a blade A _ij inside group d 'vanes indexed j.

Thus a group of blades G _j is associated with a first blade _labeled A _1i and a second blade labeled A _2j , for example, A ₁₁ corresponds to the first blade of the first blade group G ₁ and A ₂₁ corresponds to the second dawn of this same group of blades.

The chord is defined for a blade as the distance between its leading edge a _ij and its trailing edge f _ij . It is marked on the right m respectively by C _Fj for the first dawn A _1j and C _Rj for the second dawn A _2j .

It is also possible to define the total chord length C _Tj for a group of blades Gj, identified on the right m by the projection of the distance separating the leading edge a ₁₁ from the first blade, and the trailing edge f ₂₁ of the second blade for the same group of blades G _j .

The characteristics of the compression device are determined by example, from at least one parameter chosen from a set of characteristic parameters, specific to the blades and to the position of the groups blade. The choice thus makes it possible to delimit a field of operation optimal for the compression device.

• le décalage tangentiel h, correspondant à la distance entre le bord d'attaque a₂₁ de la seconde aube A₂₁ du premier groupe d'aube G₁, et le bord de fuite f₁₂ de la première aube A₁₂ du second groupe d'aube G₂. La valeur de ce paramètre est par exemple exprimée en fonction du pas t, et donné sous la forme d'un rapport h/t. Le pas t correspond à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux aubes auxiliaires A₂₁ et A₂₂ des premiers et second groupes d'aubes G₁ et G₂,
• le recouvrement axial "r_j" repéré par rapport à la direction m et qui correspond au recouvrement de la première aube A_1j du groupe d'aubes G_j et de la seconde aube A_2j du même groupe d'aubes G_j, avantageusement on définit la valeur relative de recouvrement "r_j" rapportée à la corde C_Fj de la première aube d'un groupe d'aubes,
• le rapport de corde R_Cj = (C_Fj / C_Rj) défini, par exemple, par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj, pour le groupe d'aubes G_j.

The set of parameters, from which these characteristics are selected, includes, for example, at least the following three parameters:

• the tangential offset h, corresponding to the distance between the leading edge a ₂₁ of the second blade A ₂₁ of the first group of blades G ₁ , and the trailing edge f ₁₂ of the first blade A ₁₂ of the second group of dawn G ₂ . The value of this parameter is for example expressed as a function of the step t, and given in the form of an h / t ratio. The pitch t corresponds to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the auxiliary blades A ₂₁ and A ₂₂ of the first and second groups of blades G ₁ and G ₂ ,
• the axial overlap "r _j " marked with respect to the direction m and which corresponds to the overlap of the first blade A _1j of the group of blades G _j and of the second blade A _2j of the same group of blades G _j , advantageously we defines the relative recovery value "r _j " relative to the chord C _Fj of the first blade of a group of blades,
• the chord ratio R _Cj = (C _Fj / C _Rj ) defined, for example, by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second dawn C _Rj , for the group vanes G _j .

By an appropriate choice of the values of at least one of the three parameters previously defined, it is possible to obtain a compression device optimized.

According to a preferred embodiment for the pumping device or compression according to the invention, the values of at least one of the three previously defined parameters.

• le décalage tangentiel h rapporté au pas t est compris dans l'intervalle [0,95; 1,05],
• le rapport r_j/C_Tj appartient à l'intervalle [0,0 ; 0,15],
• le rapport de corde R_Cj est compris entre [0,5 ; 1,5 ]

To define an impeller, the value of at least one of the three parameters is preferably chosen in the intervals given below:

• the tangential offset h related to the step t is included in the interval [0.95; 1.05]
• the ratio r _j / C _Tj belongs to the interval [0,0; 0.15]
• the chord ratio R _Cj is between [0.5; 1.5]

This defines a geometry for the blades and an arrangement of at least minus two groups of blades, for an impeller, in order to obtain a optimal functioning of the fluid compression device polyphasic.

Advantageously, the three parameters are chosen from the three intervals previously given and a fourth parameter chosen in combination with the first three is associated with them to optimize the compression operation. This fourth parameter is, for example the camber ratio Φ _j determined for a group of blades and defined as the ratio of the value of the camber Φ _Fj of the first blade A _1j to the value of the camber Φ _Rj of the second dawn A _2d for a given dawn group.

The value of this parameter is preferably chosen in the range [0.5; 1].

• le décalage tangentiel h rapporté au pas t est compris dans l'intervalle [0,60; 0,80],
• le rapport r_j/C_Tj appartient à l'intervalle [-0,01 ; 0,05],
• le rapport de corde R_Cj est compris entre [0,5; 1,5 ]

Identically, a rectifier is defined for example by choosing these characteristics in the following way:

• the tangential shift h related to the step t is included in the interval [0.60; 0.80]
• the ratio r _j / C _Tj belongs to the interval [-0.01; 0.05]
• the chord ratio R _Cj is between [0.5; 1.5]

This defines a geometry for the blades and an arrangement of at least at least two groups of blades, at the level of the rectifiers, making it possible to obtain preferential operation of the fluid compression device polyphasic.

In this case, the camber ratio Φ _j determined for a group of blades of a rectifier, and defined as the ratio of the value of the camber Φ _Fj of the first blade A _1j to the value of the camber Φ _Rj of the second blade A _2j for a given group of blades, is preferably chosen from the interval [0.10; 1].

According to a preferred embodiment, the following three parameters are selected to produce the impellers and / or for the rectifiers: the tangential offset h relative to the pitch t, the ratio r _j / C _Tj and the chord ratio R _Cj . This defines a field of pumping or compression devices adapted to communicate to a multiphase type fluid, for example an oil effluent, a compression value sufficient to ensure its transfer from a production location for example a source or a well. production to a place of destination, such as a processing platform or even an intermediate place, without having to separate the phases.

A section offered for the flow of fluid in an impeller and / or a rectifier is for example defined by the total area of passage of the fluid in a plane Pi perpendicular to the axis of rotation of the device and located between the input and the output of the device. The total area changes for example according to a law that is substantially constant and bounded by a minimum value of area and a maximum value, chosen so that the ratio of two areas chosen for two Pi planes as defined above is preferably included in the interval [2.2; 0.45].

It follows in particular that according to an optimized embodiment the impellers have a fluid passage area considered in their plane of limited exit according to the value of the corresponding area in their plan input.

According to one embodiment of the device, the ratio of the thicknesses maximum of the first and second vane e1 / e2, is preferably chosen in the interval [0.6; 1] for an impeller and preferably chosen in the interval [0.5; 1] for a rectifier.

According to a preferred embodiment, the characteristics geometric groups of blades for the moving or impeller wheels are defined for example by values chosen so that the diameter ratio outside of the wheel expressed in mm, on the number of blades belongs to the interval [40; 60].

According to a particular embodiment for which only the impellers have one of the characteristics of the invention as described previously, it is possible to use a rectifier of any type, known from a person skilled in the art, and which may in particular have characteristics adapted to the characteristics of the impeller stage.

At the output of an impeller stage, the multiphase fluid is animated by a speed having at least one axial component and one component circumferentially. As is well known to specialists, the use of a rectifier increases the static pressure by removing or less by reducing the circumferential components of speed fluid flow.

It is possible to realize the pumping or compression device according to the invention, to comply for example with the provisions of the various elements, for example impellers and rectifiers, given for example in one of the applicant's patents FR 2,333,139, FR 2,471,501, or FR 2,665,224.

Thus a multi-stage pumping or compression device is formed for example by a succession of several compression stages formed for example by a movable wheel (impeller) preceded or succeeded by a fixed wheel (rectifier), according to the direction of flow of the fluid. The section of passage offered to the fluid is for example substantially continuous and the flow of the fluid takes place in a preferential direction aligned with the axis of rotation of the device.

In order to better understand the phenomena acting during pumping of a multiphase fluid in a compression device comprising tandem blades, Figure 4 illustrates the different flows of the different phases, liquid and gaseous in a pumping or compression device, in particular when they flow into a channel delimited by two tandem blades.

Thus in FIG. 4, there is shown in a diagram identical to that of FIG. 3, two groups of blades G ₁ and G ₂ and dashed lines corresponding to the groups of blades G ₀ and G ₃ arranged on one side and the other of the two groups previously defined.

In this way, several fluid flow channels are identified, E ₀ , E ₁ , E ₂ located respectively between the groups of blades G ₀ and G ₁ , G ₁ and G ₂ , G ₂ and G ₃ .

To each of the blades, there is associated a reference I _ij designating the pressure side of the blade and E _ij the suction side of the blade.

For each group of blades, a flow passage is defined between the lower surface I _1j of the first blade and upper surface E _2j of the second blade, for example.

Thus, in FIG. 4, the passage p ₁ corresponds to the flow passage located between the two blades A ₁₁ , A ₁₂ of the first group of blades and p ₂ the flow passage located between the blades A ₁₂ , A ₂₂ of the second group of blades, the flow passages each having a width the value of which is fixed by the positioning of the two blades within the same group of blades.

This flow channel remixes at least part of the liquid phase from a flow channel with at least part of the gas phase flowing in an adjacent flow channel.

Indeed, during its passage through a pressurizing element, and under the effect of the rotation, there is a separation of the phases composing the multiphase fluid, in particular the separation of the liquid phase and the gaseous phase, referenced respectively l _k and g _k , with k index associated with the channel in which the fluid circulates (E ₀ , E ₁ , E ₂ ).

Under the effect of a transverse pressure gradient, the liquid phase l _k is entrained towards the face of the blade under overpressure, the lower surface of the blade while the gas phase g _k will on the contrary migrate towards the face in dawn depression or upper surface. This phenomenon is also seen in compression devices comprising blades called simple blades.

According to the diagram shown in FIG. 4, the multiphase fluid to which it is desired to communicate a certain energy value circulates between two groups of successive tandem blades, for example the flow channel E ₁ and according to the arrow E for example.

Inside this channel, the fluid decomposes into a liquid fraction l ₁ which migrates towards the lower surface side I ₁₁ of the vane A ₁₁ and a gaseous fraction g ₁ which is attracted towards the upper surface E21 of the first vane At ₁₂ of the second group of blades.

The liquid fraction l ₁ attracted by the pressure side I ₁₁ flows through the flow passage p ₁ and also opens into the flow channel E ₀ , continues to circulate until it mixes with at least part of the gas fraction g ₀ coming from the separation of the liquid and gas phases in the flow channel E ₀ .

The gas g ₀ and liquid l ₁ phases by remixing, at least partially compensate for the phenomenon of segregation of the liquid and gas phases which appears during the pumping of a multiphase fluid and which contributes to the reduction in efficiency for pumping. .

This phenomenon is reproduced at the level of each of the passages flow and therefore at the level of each group of blades, the gaseous fluids and liquid, for example from adjacent channels are remixed.

Advantageously, the presence of a flow passage between two blades of a group of blades significantly improves the performance of the devices compression compared to the yield obtained with a formed blade a single blade with substantially identical surface and equivalent geometry.

The dimension of the flow passage is for example chosen from of the set of parameters previously defined.

Figure 5 is a perspective view of a group of blades which are by example linked together by at least one mechanical element 40. Thus a first dawn is for example connected to at least the following dawn (by taking the flow direction) and / or at a previous dawn. This mechanical element 40 can be positioned anywhere along and / or across the width of a blade and can take any geometric shape that respects the flow of the fluid, that is to say which does not disturb the flow of the fluid.

Advantageously, the presence of at least one mechanical element allows to maintain the distance between the blades, and to respect the provision specific of the blades between them. It thus plays the role of mechanical reinforcement of the device.

Figure 6 shows schematically an alternative embodiment of the device according to the invention for which a group of blades is obtained from a blade provided with one or more orifices distributed over at least part of its length. The parts of the blade separated by these orifices thus form "sub-blades" which each have a function substantially identical to the function fulfilled by the blades A _ij described in FIG. 3.

The lights or orifices distributed along the blade 50 thus allow the passage of the liquid and gaseous fractions circulating respectively in the vicinity on the lower side of the dawn and on the upper side of the dawn and coming from channels adjacent, for example as described in Figure 3.

In Figure 6, there is shown a shape which can be taken by a gas pocket or liquid pocket.

The liquid fraction tends to pass through at least one of the lights 51 to mix with the gaseous fraction circulating on the upper side and thus form a multiphase mixture. In this way, we decrease notably the value of the GLR ratio, due to the enrichment of the fraction gas with a liquid part and the compression of the fluid is improved multiphase, by compensating for the separation from the compression of the multiphase fluid as previously described in relationship to Figure 4.

Mixing ports or lights may have geometries different sizes chosen, in particular depending on the nature of the phases constituting the fluid to facilitate the passage of these phases one towards the other.

Claims (14)

1. A device for compressing or for pumping a multiphase fluid comprising at least one gas phase and at least one liquid phase, the device comprising at least one hollow casing (1) with at least one inlet port (2) and at least one outlet port (3) for said fluid, at least one rotor that can rotate within said casing with an axis of rotation Ox, an impeller comprising two groups of blades including each a first blade and a second blade, the impeller being secured to the rotor, the blades of the impeller having a leading edge a_ij and a trailing edge f_ij, the angle α formed by the tangent to the curve of the skeleton, said angle being counted from the leading edge a_ij of at least one of said first and/or second blade in relation to the peripheral or tangential direction of the device, ranges between 0 and 45°, the device comprising a diffuser including two groups of blades comprising each a third and a fourth blade, characterized in that the characteristics and the position of the blades of the impeller are determined according to at least one parameter selected from the following four parameters:

   parameter 1 : the tangential offset h in relation to pitch t, expressed in the form of ratio h/t, where t is the pitch corresponding to the distance between the two trailing edges f₂₁ and f₂₂ corresponding to the second blade of each group of blades, the value of parameter 1 is in the range of values from 0.95 to 1.05,

   parameter 2 : the ratio of the axial lap r_j and of the total chord C_Tj corresponding to a group of blades which is in the range of values from 0.0 to 0.15,

   parameter 3 : the chord ratio R_Cj = (C_Fj/C_Rj) defined for a group of blades by the ratio of the value of chord C_Fj of the first blade to the value of the chord of the second blade C_Rj for one of the groups of blades ranging between 0.5 and 1.5,

   parameter 4 : the camber ratio Φ_j defined by the value of the camber Φ_Fj of the first blade to the value of the camber Φ_Rj of the second blade of the same group of blades, ranging between 0.5 and 1.
2. A device as claimed in claim 1, characterized in that the characteristics and the position of the blades of the diffuser are determined according to at least one parameter selected from the following four parameters :

   parameter 5 : the tangential offset h in relation to the pitch t, expressed in the form of the ratio h/t, where t is the pitch corresponding to the distance between the two trailing edges f₂₁ and f₂₂ corresponding to the fourth blades of each group of blades, the value of parameter 5 is in the range of values from 0.60 to 0.80,

   parameter 6 : the ratio of the axial lap r_j and of the total chord C_Tj corresponding to a group of blades which is in the range of values from -0.01 to 0.05,

   parameter 7 : the chord ratio R_Cj = (C_Fj/C_Rj) defined for a group of blades by the ratio of the value of the chord C_Fj of the third blade to the value of the chord C_Rj of the fourth blade for one of the groups of blades ranging between 0.5 and 1.5,

   parameter 8 : the camber ratio Φ_j defined by the value of the camber of the first blade to the value of the camber Φ_Rj of the second blade of the same group of blades, ranging between 0.10 and 1.
3. A device as claimed in any one of claims 1 and 2, characterized in that the geometric characteristics of the impeller blades are determined according to parameters 1, 2 and 3.
4. A device as claimed in any one of claims 2 and 3, characterized in that the geometric characteristics of the diffuser blades are determined according to parameters 5,6 and 7.
5. A device as claimed in any one of claims 3 and 4, characterized in that the geometric characteristics of the impeller blades are specified by means of parameter 4.
6. A device as claimed in any one of claims 4 and 5, characterized in that the geometric characteristics of the diffuser blades are specified by means of parameter 8.
7. A device as claimed in any one of claims 1 to 6, characterized in that the ratio of the maximum thickness of the first and of the second blades e1/e2 of the impeller ranges between 0.6 and 1.
8. A device as claimed in any one of claims 1 to 7, characterized in that the ratio of the maximum thickness of the third and of the fourth blades e1/e2 of the diffuser ranges between 0.5 and 1.
9. A device as claimed in any one of claims 7 and 8, characterized in that the thickness e1 of the first or of the third blade ranges between 2 and 10 mm and/or the thickness e2 of the second or of the fourth blade ranges between 2 and 20 mm.
10. A device as claimed in any one of the previous claims, characterized in that a blade is connected to a preceding blade and/or to the next blade by means of a mechanical element (40).
11. A device as claimed in any one of claims 1 to 10, characterized in that said impeller is arranged before said diffuser in relation to the direction of flow of the fluid.
12. A device as claimed in any one of claims 1 to 10, characterized in that it comprises at least two diffusers, said impeller being arranged between the two diffusers.
13. A device as claimed in any one of the previous claims, the impeller blades comprising a first face or upper face and a second face or lower face, the blades being provided over at least part of their length with one or more openings (51) allowing to communicate said two upper and lower faces so as to favour meeting of at least part of the gas phase flowing in the vicinity of the upper face and of at least part of the liquid phase circulating on the lower face side.
14. Use of the device as claimed in any one of the previous claims for pumping a multiphase effluent.

Images