Patent Description:
Turbomachines, for example rotary compressors and rotary turbines, are machines designed to process a working fluid that flows inside a flow path during operation of the machine. A turbine transfers energy from the working fluid to a rotor of the machine. A compressor transfers energy from a rotor of the machine to the working fluid. The flow path is defined partially by surfaces of a rotor of the machine and partially by surfaces of a stator of the machine.

During operation, a turbomachine, in particular the surfaces delimiting its flow path, gets dirty; this is particularly true for turbomachines used in the "Oil & Gas" industry. Dirt may derive from the composition of the working fluid and/or from substances or droplets or particles carried by the working fluid. Dirt may stick even firmly to the surfaces delimiting the flow path; typical surfaces that get dirty are the airfoil surfaces of (rotary) blades and (stationary) vanes of a turbomachine.

<CIT> discloses a compressor comprising a guide vane having a washing system. <CIT> discloses an engine compressor wash system. <CIT> discloses a steam turbine with an extraneous matter removing system. A solution for cleaning a gas turbine compressor is known from US patent application published as "<CIT>". According to <CIT>, a washing assembly is located at the bellmouth of the compressor upstream of its struts, and includes a number of nozzles ejecting water droplets.

A washing assembly located at the bellmouth of the compressor upstream of its struts is easy to be installed as the bellmouth is quite big and is easily accessible being at the inlet of the machine.

However, a washing assembly located at the bellmouth of the compressor upstream of its struts is fully effective only in cleaning the struts.

Accordingly, it would be desirable to have a cleaning system and method effective in cleaning (stationary) vanes and/or (rotary) blades of a turbomachine, preferably also (stationary) vanes and/or (rotary) blades far from the inlet of the turbomachine.

According to an aspect, the subject-matter disclosed herein relates to a stator aerodynamic component to be placed inside a flow path of a working fluid of a turbomachine; the component comprises: a duct arranged to receive a washing liquid from a pipe, and one or more nozzles fluidly connected to said duct and arranged to eject liquid into the flow path; the one or more nozzles are located internally to poles projecting from airfoil surfaces of the stator aerodynamic component.

The stator aerodynamic components as disclosed herein are used to eject a washing liquid being for example water, in particular demineralized water, and possibly a detergent.

In order to clean a dirty surface, a washing liquid, for example water, may be sprayed onto the surface from one or more nozzles. Cleaning is very effective if the nozzle is very close to the surface to be cleaned. Dirt deposits on blades disturb aerodynamic flow around them leading to loss of entire turbine efficiency; furthermore, uneven dirt deposits on blades may cause vibrations; thus effective washing of blades is advantageous.

In a turbomachine, a strut or a (stationary) vane is positioned near an array of (rotary) blades that are immediately downstream of the strut or vane. During rotation of the rotor, the distance between a blade of the array and the strut or vane first decreases, reaches a minimum and then increases. To be more precise, during rotation of the rotor, the distance between a leading edge region of the blade of the array and a trailing edge region of the strut or vane first decreases, reaches a minimum and then increases.

As disclosed herein, it has been discovered that a specially configured stator aerodynamic component, for example a strut or a (stationary) vane, equipped with at least one nozzle, may advantageously be used for ejecting a washing liquid from the at least one nozzle that washes (rotary) blades and/or (stationary) vanes downstream, preferably immediately downstream, of the strut or vane. Nozzles for ejecting the washing liquid may advantageously be located at the trailing edge region of the stator aerodynamic component.

As the strut or vane is stationary, the washing liquid may be easily fed to the strut or vane in a continuous manner through e.g. a pipe from a supply system that may be external to the turbomachine.

Use of embodiments of the new stator aerodynamic component is contrary traditional approaches for washing turbomachines, which wash from the exterior of the turbomachine. Advantageously, embodiments of the new stator aerodynamic component and turbomachine "interior" washing method may be used for any (rotary) blades and/or (stationary) vanes even if they are far from the inlet and outlet of the turbomachine, because the cleaning system (e.g., at least a stator aerodynamic component equipped with at least one wash nozzle) is integrated into what are considered to be normal components of the turbomachine, and/or fits within the interior dimensions / spatial volume of the turbomachine to clean from the inside (or interior) of the turbomachine.

Referring now to the drawings, <FIG> shows a partial schematic longitudinal-section view of an embodiment of a turbomachine, namely a compressor <NUM>.

Compressor <NUM> is divided into a bellmouth section <NUM> and a compression section <NUM>. Section <NUM> is enclosed in a bellmouth section casing <NUM> that is part of the stator of the compressor. Section <NUM> is enclosed in a compression section casing <NUM> that is part of the stator of the compressor. Casings <NUM> and <NUM> are joined together and may be in a single piece or in multiple pieces fixed between each other. A flow path <NUM> stretches inside compressor <NUM>. A rotation axis of the compressor <NUM> is indicated as XX.

Bellmouth section <NUM> includes an array of struts <NUM> that are parts of the stator of the compressor.

Compression section <NUM> includes stator vanes and rotor blades. In particular, moving from the inlet to the outlet, i.e. from a low-pressure side of the compressor (on the left of <FIG>) to a high-pressure side of the compressor (on the right of <FIG>), there is a first array of vanes <NUM>, a first array of blades <NUM> (belonging to a first compression stage of the compressor), a second array of vanes <NUM>, a second array of blades <NUM> (belonging to a second compression stage of the compressor). The vanes <NUM> and <NUM> are parts of the stator, and the blades <NUM> and <NUM> are parts of the rotor.

Flow path <NUM> is partially defined by the airfoil surfaces of struts <NUM>, vanes <NUM> and <NUM>, blades <NUM> and <NUM>; in other words, these aerodynamic components are placed inside flow path <NUM> of a working fluid of turbomachine <NUM>.

According to the embodiment of <FIG>, compressor <NUM> includes two cleaning assemblies, one in the bellmouth section <NUM> and one in the compression section <NUM>. It is to be noted that according to variants of this embodiment, there may be only one cleaning assembly (for example only the one assembly in the bellmouth section <NUM> or only the one assembly in the compression section <NUM>), or three cleaning assemblies (i.e. an assembly in the bellmouth section <NUM> and two assemblies in the compression section <NUM>, one for each compression stage of the compressor), or even more cleaning assemblies.

The first cleaning assembly in <FIG> includes a duct <NUM> and e.g. three nozzles <NUM> fluidly connected to duct <NUM> through e.g. three channels <NUM>. Duct <NUM> receives a washing liquid from a pipe <NUM>; in particular, duct <NUM> is completely internal to strut <NUM> and pipe <NUM> comes from outside of compressor <NUM>, goes through casing <NUM> and reaches duct <NUM>. The nozzles eject the washing liquid into flow path <NUM>. It is to be noted that according to variants of this embodiment, the number of nozzles may vary but being greater than one.

As can be appreciated from e.g. <FIG>, compressor <NUM> has a number of struts <NUM>, in particular six struts. In the embodiment of <FIG>, at least one of the struts has a duct and one or more nozzles; however, preferably, this is replicated in one or two or three or more or all the struts (as shown in <FIG>).

Washing liquid ejected from nozzles <NUM> is very effective in cleaning vanes <NUM> of turbomachine <NUM> being immediately downstream of struts <NUM> of turbomachine <NUM>. Washing liquid ejected from nozzles <NUM> is still effective in cleaning blades <NUM> of turbomachine <NUM> being in turn immediately downstream of vanes <NUM> of turbomachine <NUM>.

The second cleaning assembly in <FIG> includes a duct <NUM> and e.g. two nozzles <NUM> fluidly connected to duct <NUM> through e.g. two channels <NUM>. Duct <NUM> receives a washing liquid from a pipe <NUM>; in particular, duct <NUM> is completely internal to vane <NUM> and pipe <NUM> comes from outside of compressor <NUM>, goes through casing <NUM> and reaches duct <NUM>. The nozzles eject the washing liquid into flow path <NUM>. It is to be noted that according to variants of this embodiment, the number of nozzles may vary but being greater than one.

As can be appreciated, compressor <NUM> has a number of vanes <NUM>. In the embodiment of <FIG>, at least one of the vanes <NUM> has a duct and one or more nozzles; however, preferably, this is replicated in one or more or all the vanes.

Washing liquid ejected from nozzles <NUM> is very effective in cleaning blades <NUM> of turbomachine <NUM> being immediately downstream of vanes <NUM> of turbomachine <NUM>.

From the above, it is apparent that the stator aerodynamic component comprising a cleaning assembly may be a bellmouth strut (for example strut <NUM>) or an inlet guide vane (for example vane <NUM>) or intermediate guide vane (for example vane <NUM>).

Referring to <FIG>, a stator aerodynamic component, for example strut <NUM>, may be divided into a leading edge region <NUM>, a trailing edge region <NUM> and an intermediate region <NUM>. According to these embodiments, nozzles <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> of the component are located in trailing edge region <NUM> so to be in a favorable position for effective ejecting washing liquid; however, nozzles <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> are arranged differently as explained later. According to these embodiments outside the subject-matter of the claims, the duct <NUM> of the component is located in leading edge region <NUM> where there is big space for housing even a big strut; it is to be noted that the position of duct <NUM> in these three figures is the same but it may be different according to other embodiments.

Referring to <FIG>, there is at least one nozzle <NUM>-<NUM> (receiving washing fluid from a channel <NUM>-<NUM>) arranged to eject washing liquid in an ejection direction ED-<NUM> corresponding to a flow direction FD of flow path <NUM>; regarding the angle, you may consider a tolerance of +/-<NUM>°. In this case, the nozzle is on the tip of trailing edge region <NUM>.

Referring to <FIG>, there is at least one nozzle <NUM>-<NUM> (receiving washing fluid from a channel <NUM>-<NUM>) arranged to eject washing liquid in an ejection direction ED-<NUM> inclined with respect to a flow direction FD of flow path <NUM>, the inclination being between -<NUM>° and -<NUM>°; regarding the angle, you may consider a tolerance of +/-<NUM>°. In this case, the nozzle is on a first lateral surface of trailing edge region <NUM>.

Referring to <FIG>, there is at least one nozzle <NUM>-<NUM> (receiving washing fluid from a channel <NUM>-<NUM>) arranged to eject washing liquid in an ejection direction ED-<NUM> inclined with respect to a flow direction FD of flow path <NUM>, the inclination being between +<NUM>° and +<NUM>°; regarding the angle, you may consider a tolerance of +/-<NUM>°. In this case, the nozzle is on a second lateral surface of trailing edge region <NUM>.

It is to be noted that a nozzle may be designed to eject liquid in different directions, i.e. its ejection looks like a wide cone; alternatively, a cone-shaped ejection from a component may derive from the combination of the ejections from a set of nozzles mounted to the component.

It is further to be noted that nozzles of the same component may be arranged to eject liquid in different directions. For example, with reference to <FIG>, the upper (first radial position) nozzle of strut <NUM> may eject in a first direction, the middle nozzle (second radial position) of strut <NUM> may eject in a second direction, the lower nozzle (third radial position) of strut <NUM> may eject in a third direction.

Referring to <FIG> concerning embodiments not according to the claimed invention, the component has a removable part <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, and the nozzles <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> are located in the removable part <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. In general, in embodiments different from these figures, the nozzles of the cleaning assembly and/or the duct of the cleaning assembly may be located in the removable part. The removal part may be useful in order to facilitate repairing compressor <NUM>. The removal part may be useful in order to facilitate customizing compressor <NUM> to the requirement of e.g. a customer; in fact, for example, the body of strut <NUM> in these figures remain the same and, based on a request or a requirement, it is possible to easily mount part <NUM>-<NUM> or part <NUM>-<NUM> or part <NUM>-<NUM> to the body.

<FIG> shows a possible positioning of multiple nozzles at the struts <NUM> of compressor <NUM> of <FIG> not encompassed by the wording of the claims. There are nozzles located on the tips of the trailing edge regions of the struts. There are also nozzles <NUM> located on an inner wall delimiting flow path <NUM> at bellmouth section <NUM>. There are also nozzles <NUM> located on an outer wall delimiting flow path <NUM> at bellmouth section <NUM>. These three positioning may be combined in any possible way independently from the specific combination shown in <FIG>.

It is to be noted that, even if this is not shown in any figure, nozzles may be located on an inner and/or an outer wall delimiting flow path <NUM> at positions different from bellmouth. In this case, they may be located between a first stage (for example blades <NUM>) of compressor <NUM> and a last stage (for example blades <NUM>) of compressor <NUM>, for example close to vanes (for example vanes <NUM>).

Referring to <FIG> and <FIG> and <FIG>, three embodiments of a stationary vane <NUM>, namely <NUM>-<NUM> and <NUM>-<NUM> and <NUM>-<NUM> not according to the claimed invention, are shown and their effect on rotary blades <NUM> of a compression stage of compressor <NUM> - arrow R shows the rotation direction of blades <NUM>. In the embodiment of <FIG>, a nozzle <NUM>-<NUM> is located on the tip of the trailing edge and ejects washing liquid in an ejection direction ED-<NUM> corresponding to flow direction FD of flow path <NUM>. In the embodiment of <FIG>, a nozzle <NUM>-<NUM> is located on the tip of the trailing edge and ejects washing liquid in an ejection direction ED-<NUM> inclined with respect to flow direction FD of flow path <NUM> by an angle A-<NUM> of approximately e.g. -<NUM>°. In the embodiment of <FIG>, a nozzle <NUM>-<NUM> is located on the tip of the trailing edge and ejects washing liquid in an ejection direction ED-<NUM> inclined with respect to flow direction FD of flow path <NUM> by an angle A-<NUM> of approximately e.g. +<NUM>°.

Nozzles <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> eject washing liquid so to reach blades <NUM>; in particular, ejection form one nozzle reach only one blade at a time (or a limited number of vane at a time, for example two or three or four). According to these embodiments, nozzles <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> eject washing liquid so to reach both the pressure side and the suction side of blades <NUM>; in <FIG>, portion from V to P1-<NUM> of suction side is reached by washing liquid and portion from V to P2-<NUM> of pressure side is reached by washing liquid, in <FIG>, portion from V to P1-<NUM> (i.e. all) of suction side is reached by washing liquid and (small) portion from V to P2-<NUM> of pressure side is reached by washing liquid; in <FIG>, (small) portion from V to P1-<NUM> of suction side is reached by washing liquid and portion from V to P2-<NUM> (all) of pressure side is reached by washing liquid. In general, the quantity of washing liquid reaching the pressure side may be equal to or different from the quantity of washing liquid reaching the suction side.

As it is apparent from the above description, the cleaning methods disclosed herein provide that blades and/or vanes of a turbomachine are washed by ejecting a washing liquid from at least one stator aerodynamic component placed inside a flow path of a working fluid of the turbomachine; in particular, the washing liquid is ejected from one or more nozzles at least one stator aerodynamic component. The blades may be blades of a first stage of the turbomachine and/or blades of an intermediate stage of the turbomachine and/or blades of a last stage of the turbomachine. The vanes may be vanes of a first vanes array of the turbomachine and/or vanes of an intermediate vanes array of the turbomachine and/or vanes of a last vanes array of the turbomachine.

The stator aerodynamic components as disclosed herein may be used to eject a washing liquid being for example water, in particular demineralized water, and possibly a detergent. The composition of the washing liquid may depend on when (for example in operating mode or in non-operating mode) and/or where cleaning is carried out. However, the stator aerodynamic components as disclosed herein may be used to eject other liquids useful for specific applications in a turbomachine.

The cleaning method as disclosed herein may be carried out online and/or offline. In other words, the nozzles in the stator aerodynamic components may be activated when the turbomachine is operative, when the turbomachine is non-operative (but rotating) and both in operating mode and in non-operating mode.

The washing liquid may be ejected for example in continuous manner or in pulsating manner.

During cleaning as disclosed herein, at least one parameter may be set or controlled when the blades and/or the vanes are washed. Such parameter may be for example temperature of the washing liquid, pressure of the washing liquid, composition of the washing liquid, ejection velocity of the washing liquid, ejection direction of the washing liquid.

<FIG> show a stator aerodynamic component, in particular a strut, of the turbomachine of <FIG> wherein the fluid connection between nozzle and duct is according to extreme cases.

In <FIG>, a duct <NUM>-<NUM> is directly fluidly connected to a nozzle <NUM>-<NUM> that ejects washing liquid in direction ED-<NUM>; in other words, the connection channel has length equal to zero (i.e. no connection channel); the duct has roughly the same cross-section area as the stator aerodynamic component.

In <FIG>, according to the claimed invention a duct <NUM> is fluidly connected to at least two nozzles <NUM>-<NUM> that eject washing liquid in direction ED-<NUM> through a long channel <NUM>-<NUM> that, in particular, is branched (a first branch goes to a first nozzle <NUM>-<NUM> and a second branch goes to a second nozzle <NUM>-<NUM>); nozzles <NUM>-<NUM> are located respectively on poles <NUM> that may project from the airfoil surface of the stator aerodynamic component (a first branch is internal to a first pole and a second branch is internal to a second pole) and that may have an aerodynamic cross-section for example smaller than the cross-section of the component (as e.g. in <FIG>). The poles <NUM> may be movable (for example, they can rotate and/or translate) so that they may be located internally to the stator aerodynamic component when not used for ejecting the liquid. Such movement may be advantageously caused by a pressure of the liquid to be ejected; for example, when the pressure increases a pole moves, by effect of the pressure, out of the component and the liquid is ejected and when the pressure decreases a pole moves back, by effect of the pressure, into the component and the liquid is no longer ejected.

<FIG> shows a flow chart <NUM> of a cleaning method. This cleaning method comprises the steps of:- step <NUM>: washing blades and/or vanes of a turbomachine by ejecting a washing liquid from at least one stator aerodynamic component placed inside a flow path of a working fluid of the turbomachine, and.

The at least one parameter is selected from the group comprising temperature of the washing liquid, pressure of the washing liquid, composition of the washing liquid, ejection velocity of the washing liquid, ejection direction of the washing liquid. It is to be noted that these two steps can be performed in any suitable order and/or repeated one or more times, although in <FIG> there is only one step <NUM> and only one step <NUM>. and step <NUM> precedes step <NUM>.

Claim 1:
A stator aerodynamic component to be placed inside a flow path (<NUM>) of a working fluid of a turbomachine (<NUM>), the component (<NUM>, <NUM>) comprising:
- a duct (<NUM>, <NUM>) arranged to receive a washing liquid from a pipe (<NUM>, <NUM>),
and
- one or more nozzles (<NUM>, <NUM>) fluidly connected (<NUM>, <NUM>) to said duct (<NUM>, <NUM>) and arranged to eject liquid into said flow path (<NUM>);
characterized in that said one or more nozzles (<NUM>-<NUM>) are located internally to poles (<NUM>) projecting from airfoil surfaces of the stator aerodynamic component.