WO2019048319A1

WO2019048319A1 - Kinetic turbopump with speed-varying device for a closed circuit, particularly of the rankine cycle type, notably for a motor vehicle

Info

Publication number: WO2019048319A1
Application number: PCT/EP2018/073300
Authority: WO
Inventors: Pascal SMAGUE; Philippe Pagnier; Pierre Leduc; Gabriel Henry; Arthur Leroux; Christophe LECHARD; Benoît TALVARD; Richard Tilagone; Stephane Venturi
Original assignee: IFP Energies Nouvelles; Enogia
Priority date: 2017-09-06
Filing date: 2018-08-30
Publication date: 2019-03-14
Also published as: EP3679253A1; FR3070725B1; JP2020532679A; FR3070725A1

Abstract

The present invention relates to a turbopump comprising a fixed casing (12, 12'; 112) comprising a pump (16, 116) with a pump rotor (14, 114) borne by a pump shaft (18, 118) and a turbine (22, 122) housing a turbine rotor (20, 120) borne by a turbine shaft (24, 124). According to the invention, the pump shaft (18, 118) is separate from the turbine shaft (24, 124) and the turbopump comprises a speed-varying device (26, 126) for generating a difference in rotational speed between the pump shaft (118, 118) and the turbine shaft (24, 124).

Description

The present invention relates to a kinetic turbopump for a closed circuit, in particular of a Rankine cycle type, for example a kinetic turbopump for a closed circuit, in particular of the Rankine cycle type. , especially for a motor vehicle.

By kinetic turbopump it is understood, an assembly formed by a pump and a turbine.

The pump has the particularity that its rotor carries a multiplicity of radial fins to form an impeller whose effect is the setting in rotation and the acceleration of the fluid in liquid condition. By the effect of the rotation of the impeller of the pump, the fluid is drawn axially, then accelerated radially and discharged by the volute usually contained in a turbopump. The turbine, which is connected to the pump on the same shaft, consists of a stator part having a fixed blade called diffuser to convert the fluid pressure into a vapor condition into kinetic energy. This kinetic energy is then converted into mechanical energy through a moving blade of the rotor part of the turbine. The blades of the turbine consist of radial fins for the relaxation of the fluid which is ejected

As is widely known, a Rankine cycle is a thermodynamic cycle by which heat from an external heat source is transmitted to a closed circuit that contains a working fluid. During the cycle, the working fluid undergoes phase changes (liquid / vapor).

This type of cycle is generally broken down into a step during which the working fluid used in liquid form is compressed isentropically, followed by a step where the compressed liquid fluid is heated and vaporized in contact with a heat source.

This steam is then relaxed, in another step, in an expansion machine, then, in a final step, this expanded steam is cooled and condensed in contact with a cold source.

In order to carry out these various steps, the circuit comprises at least one pump for circulating and compressing the fluid in liquid form, a heat exchanger evaporator which is swept by a hot fluid to effect the at least partial vaporization of the compressed fluid, an expansion machine for relaxing the steam, such as a turbine, which converts the energy of this vapor into another energy, such as an energy mechanical or electrical, and a heat exchanger-condenser by which the heat contained in the steam is transferred to a cold source, usually outside air, or a cooling water circuit, which sweeps this condenser, to transform this steam in a fluid in liquid form. In this type of circuit, the fluid used is generally water but other types of fluids, for example organic fluids or mixtures of organic fluids, can also be used. The cycle is then called Organic Rankine Cycle or ORC (Organic Rankine Cycle). By way of example, the working fluids may be butane, ethanol, hydrofluorocarbons, ammonia, carbon dioxide, etc.

As is well known, the hot fluid for vaporizing the compressed fluid can come from various hot sources, such as a coolant (a combustion engine, an industrial process, a furnace, etc. .), hot gases resulting from combustion (fumes from an industrial process, a boiler, exhaust gas from a combustion engine or turbine, etc.), heat flow from solar thermal collectors or a geothermal source, etc.

Generally and as better described in WO 2013/046885, the pump and the turbine are combined in one piece to form a compact turbopump.

The shaft of this turbopump, which is common to the pump and the turbine, can be rotated in several ways.

As described in the French patent application No. 3,002,279 the shaft is coupled to the crankshaft of the internal combustion engine, generally by a belt surrounding a pulley placed on this crankshaft and another pulley of link placed on this shaft, being controlled by a controlled-control coupling.

It is also known from US patent application 2015/0064039 a turbopump in which the pump shaft and the turbine shaft are separated from each other. In this turbopump, a mechanical device, such as a gear train, is placed between the two shafts to change the direction of rotation of the turbine.

This device thus makes it possible to turn the turbine, for a functioning configuration in a Rankine cycle circuit, in a first direction of rotation so that it acts as a turbine while being associated with the pump contained in this turbopump or, in a reverse direction of rotation, for an operating configuration in an air conditioning circuit, so that the turbine operates as a pump while being disconnected from the pump of the turbopump.

All these turbopumps of the prior art have a significant disadvantage in the sense that the turbine rotates at the same rotational speed as the pump. Thus, the speed of the turbine can be low compared to an optimal rotational speed, which can reduce its performance.

The present invention provides a turbopump that allows the turbine to have a significantly higher rotational speed than that of the combustion engine while having a pump rotation speed lower than that of the turbine.

The efficiency of the pump is improved by this moderate speed while the efficiency of the turbine is improved by the use of a higher speed.

To this end, the present invention relates to a turbopump comprising a stationary housing comprising a kinetic pump with a pump rotor carried by a pump shaft and a turbine housing a turbine rotor carried by a turbine shaft. The pump shaft is separated from the turbine shaft and in that said turbopump comprises a speed variation device for generating a difference in rotational speed between the pump shaft and the turbine shaft. According to one embodiment of the invention, said turbopump comprises a speed variation device for reducing the speed of rotation of the pump shaft relative to the turbine shaft or for multiplying the speed of rotation of the shaft. of turbine relative to the pump shaft.

Advantageously, the pump and turbine shafts are substantially parallel to one another.

In one aspect, the speed variation device comprises a gear wheel carried by the pump shaft and a pinion carried by the turbine shaft.

In accordance with one embodiment, the pump and turbine shafts are substantially coaxial with each other.

According to one characteristic, the speed variation device comprises an epicyclic gear train.

Advantageously, the sun gear of the epicyclic gear is carried by the turbine shaft.

Advantageously, the planet carrier of the epicyclic gear is carried by a fixed wall of the turbopump housing.

Alternatively, the planet carrier of the epicyclic gear is carried by the pump shaft.

According to one embodiment, the ring of the epicyclic gear is carried by a fixed wall of the turbopump housing.

Alternatively, the ring of the epicyclic gear is carried by the pump shaft.

According to one implementation, it comprises a connecting pulley carried by the pump shaft.

According to one characteristic, the turbopump comprises a controlled-controlled coupling for connecting the connecting pulley and the pump shaft.

According to one aspect, the turbopump comprises a speed variation means between the turbine shaft and a connecting pulley.

Advantageously, it comprises an electric machine driving the pump shaft. In addition, the invention relates to an application of a turbopump according to one of the preceding characteristics to a closed circuit, in particular of the Rankine or ORC (Organic Rankine Cycle) type.

The other features and advantages of the invention will appear on reading the description which follows, given by way of illustration and not limitation, and to which are appended:

- Figure 1 which shows a sectional view of an embodiment of a turbopump according to the invention;

FIG. 2 which is a sectional view of another embodiment of a turbopump according to the invention and

- Figures 3 to 8 which show sectional views of different variants of Figure 2.

FIG. 1 shows a turbopump 10 for a closed circuit, in particular of the Rankine cycle type, in particular for a motor vehicle. The turbopump 10, which is here a kinetic turbopump, comprises a stationary housing 12 which houses the rotating part 14 (or rotor) of a means for circulating and compressing a fluid 1 6, called a pump, carried by a pump shaft. pump 18, and another fixed housing 12 'housing the rotating part 20 (or rotor) of a means of expansion of a compressed fluid 22, said turbine, carried by a turbine shaft 24.

In the example of FIG. 1, the turbopump has the particularity that the two shafts 18 and 24 are separated from one another and are placed above one another substantially parallel to each other. the other.

As best seen in FIG. 1, the two shafts are separated (or distinct) from one another and are connected to one another by a speed variation device 26 which makes it possible to generate a speed difference of rotation between the pump shaft and the turbine shaft.

More particularly, the function of the speed variation device is to multiply the speed of rotation between the pump shaft and the turbine shaft when the pump shaft gives the rotational speed pulse or to reduce the speed. rotation between the turbine and the pump when the turbine shaft generates the rotation speed, as will be explained in detail in the following description.

The speed variation device comprises a gear train 28 with a gear wheel 30, of large diameter, carried by the pump shaft 18 and which cooperates with a pinion 32, of smaller diameter than that of the wheel, carried by the turbine shaft 24, the wheel and the pinion being advantageously placed in the same vertical plane.

The difference in diameter between the wheel and the pinion thus makes it possible to produce a speed ratio between the two shafts, this speed ratio preferably being between 2 and 6 in the context of the present invention.

Thus in order to obtain the desired gear ratios between the two shafts 18 and 24, it is sufficient to set the diameters of the wheel and pinion to obtain these ratios.

This turbopump also comprises a link pulley 34 which is rotatably connected to the pump shaft 18 through a controlled-control coupling 36, here an electromagnetic type clutch.

This pulley is controlled in rotation by a band closed on itself, such as a chain or a connecting belt 38.

This band is advantageously connected to a crankshaft pulley which is connected in rotation with the crankshaft of an internal combustion engine (not shown). An alternative is to replace the mechanical connection (pulley and electromagnetic clutch) by an electric generator so as to constitute a turbo-pump-generator.

The turbopump as described above can be used in many fields, such as oilfields, aeronautics, automobiles ...

This turbopump finds its application more particularly with a closed circuit, in particular of Rankine cycle type 40 as illustrated in FIG. This Rankine cycle closed circuit is advantageously of the ORC (Organic Rankine Cycle) type and uses an organic working fluid or mixtures of organic fluids, such as butane, ethanol and hydrofluorocarbons.

It is understood that the closed circuit can also operate with a fluid such as ammonia, water, carbon dioxide ...

Thus, the outlet 42 of the pump 1 6 is connected to an inlet 44 of a heat exchanger 46, called evaporator, which is traversed by the working fluid compressed by the pump and through which the working fluid reaches the outlet 48 of this evaporator in the form of compressed steam.

This evaporator is also traversed by a hot source 50, in liquid or gaseous form so as to transfer its heat to the working fluid. This hot source makes it possible to carry out the vaporization of the fluid and can come from various hot sources, such as a cooling liquid of a combustion engine, an industrial process, a furnace, hot gases resulting from combustion (exhaust gas from a combustion engine, fumes from an industrial process, a boiler, or a turbine, etc.), heat flux from solar thermal collectors, geothermal source, etc.

The outlet of the evaporator is connected to an inlet 52 of the turbine 22 to admit the working fluid in the form of vapor compressed at high pressure, this fluid emerging through an outlet 54 of this turbine in the form of low-pressure vapor pressure.

The outlet of the turbine is connected to an inlet 56 of a cooling exchanger 58, or condenser, which makes it possible to transform the low-pressure vapor it receives into a low-pressure liquid fluid to introduce it to an inlet 60 of the pump. This condenser is swept by a cold source, usually a flow of ambient air or cooling water, so as to cool the expanded steam so that it condenses and turns into a liquid. Of course, the various elements of the circuit are interconnected by fluid circulation lines for connecting them successively to each other. Thus in operation and in the start-up phase of the closed circuit, the internal combustion engine is operational and it is necessary to prime the pump 1 6 of the turbopump. To do this, the shaft 18 is coupled to the connecting pulley 34 of the turbopump by the clutch 36. The rotational movement of the crankshaft is then transmitted to the connecting pulley 34 by the connecting belt 38. This movement of rotation is then relayed back to the pump shaft and the pump rotor.

During this rotational movement of the pump shaft, which is the rotational movement generating element, the toothed wheel 30 meshes with the pinion 32. Given the speed ratio resulting from the difference in diameter between the wheel and the pinion, the shaft 24 of the turbine rotates at a speed greater than that of the pump shaft and thus the turbine rotates at a higher speed than that of the pump.

The speed variation device 26 thus has a speed multiplier function between the pump and the turbine.

After this start-up phase, the turbine produces more power than the consumption of the pump and consequently this turbine then becomes the generating element of rotational movement to the detriment of the pump. The internal combustion engine is still operational and the shaft 18 is coupled to the pulley 34 of the turbopump via the clutch 36.

The power generated by the turbine 22 is transmitted to the pinion 32 which transmits it to the toothed wheel 30 and then to the pulley 34 of the turbopump. The power of the pulley 34 is then transmitted by the belt 38 to the crankshaft pulley which will bring extra power to the crankshaft and therefore to the internal combustion engine. This goes therefore to assist the work requested the engine and thus reduce the fuel consumption of the engine. In this configuration, the speed variation device 26 has a speed reduction function between the turbine shaft and the pump shaft.

Indeed, unlike the startup phase, the rotational movement is transmitted from the pinion to the toothed wheel. Given the gear ratio, the gearwheel, and therefore the pump, will run at a slower speed than that of the pinion of the turbine shaft. In this way, the turbine can have a rotational speed much higher than the rotational speed of the motor and the pump, which is favorable to the efficiency of the turbine. Referring now to Figure 2 which shows another embodiment of a turbopump according to the invention.

The turbopump 1 10, which is also a kinetic turbopump, comprises a fixed housing 1 12 which houses a rotor 1 14 of a pump 1 1 6 carried by a pump shaft 1 18, and a rotor 120 of a turbine 1 22 carried a turbine shaft 124.

In the example of Figure 2, the shafts of the pump and the turbine are separated from each other while being in the extension of one another, and preferably coaxially.

Advantageously, the shaft of the pump 1 18 coaxially passes through the shaft of the turbine 124, which is thus hollow, to open beyond the turbine.

As for the example of FIG. 1, the two shafts are connected to one another by a speed variation device 1 26.

This device also makes it possible to generate a difference in speed of rotation between the pump shaft and the turbine shaft.

Similarly to the example described in FIG. 1, the function of the speed variation device is to multiply the speed of rotation between the pump shaft and the turbine shaft when the pump shaft gives the speed pulse. rotating or reducing the speed of rotation between the turbine and the pump when the turbine shaft generates the rotational speed as will be explained in detail in the following description. This speed variation device comprises an epicyclic gear train 128 whose sun gear 130 is carried by the hollow shaft of the turbine 124, whose ring 132 is carried by the pump shaft 1 18, and whose planet carrier 134 is carried by a vertical wall 135 of the housing 1 12.

This turbopump also comprises a link pulley 136 which is rotatably connected to the pump shaft 1 18 through a controlled-control coupling 138, of the electromagnetic clutch type, and which is rotated by a closed band on it. itself, such as a chain or a connecting belt 140.

This band is advantageously connected to a crankshaft pulley which is connected in rotation with the crankshaft of an internal combustion engine (not shown).

As for the example of FIG. 1, this turbopump more particularly finds its application for a closed circuit, in particular of the Rankine cycle type.

For this, the outlet 142 of the pump 1 16 is connected to an inlet of an evaporator, which is traversed by the working fluid compressed by the pump, the outlet of the evaporator is connected to an inlet 144 of the turbine 122 for admitting the working fluid in the form of vapor compressed at high pressure, this fluid emerging through an outlet 146 of the turbine in the form of low-pressure expanded steam.

The outlet of the turbine is connected to an inlet of a condenser, which makes it possible to convert the low-pressure vapor it receives into a low-pressure liquid fluid to introduce it to an inlet 148 of the pump.

The operation of this turbopump is similar to that of Figure 1.

Thus, in the start-up phase of the closed circuit, the internal combustion engine is operational and it is necessary to prime the pump 1 1 6 of the turbopump. To do this, the shaft 1 18 is coupled to the connecting pulley 136 of the turbopump by the clutch 138. The rotational movement of the crankshaft is then transmitted to the connecting pulley by the connecting belt 140. This rotational movement is then retransmitted to the pump shaft and the pump rotor as well as to the ring gear 132 of the planetary gear train 128.

During the rotational movement of the crown, which is the generating element of rotational movement, this crown meshes with the planet carrier which is fixed. The rotation movement of the satellites of this planet carrier is communicated to the sun gear 130 and then to the shaft of the turbine.

In this configuration, the planetary gear train has a speed ratio that increases the speed of the sun gear relative to that of the crown. By this the turbine rotates at a speed greater than that of the pump.

The epicyclic train 128 thus has a speed multiplier function between the pump and the turbine with a first multiplier speed ratio for the turbine with a rotational speed transmission between the crown, the planet carrier and the sun gear.

After this start-up phase, the turbine produces more power than the consumption of the pump and consequently this turbine then becomes the generating element of rotational movement to the detriment of the pump.

The internal combustion engine is still operational and the shaft 1 18 is coupled to the pulley 136 of the turbopump by the clutch 138.

The power generated by the turbine 122 is transmitted to the sun gear 130 which transmits it to the ring gear 132 through the planet carrier 134. The power of the ring gear is transmitted to the turbine shaft and to the pulley 136 of the turbopump.

The power of the pulley is then transmitted by the belt 140 to the crankshaft pulley which will bring extra power to the crankshaft and therefore to the internal combustion engine.

In this configuration, the speed variation device 126 has a speed reduction function between the turbine shaft and the pump shaft with a first reduction ratio for the pump with a transmission of rotation between the sun gear, the planet carrier and the crown. The advantage of this configuration is to allow the turbine a rotational speed much higher than the rotational speed of the motor and the pump, which is favorable to the efficiency of the turbine.

The variant of FIG. 3 comprises the same elements as those of FIG. 2 but with a particular arrangement of the epicyclic gear train 128. In this configuration, the sun gear 130 is carried by the hollow shaft of the turbine 124, the ring 132 is carried by a vertical wall 135 of the housing 1 12, and the planet carrier 134 is carried by the shaft of the pump 1 18.

This operation of this epicyclic gear configuration is similar to that of FIG. 2 with a speed multiplier function between the pump and the turbine, with a second multiplier speed ratio for the turbine, during the transmission of rotation speed between the planet carriers, the crown, and the sun gear. The variant of Figure 4 also comprises the same elements as those of Figure 2 or 3 but with a particular arrangement of the epicyclic gear train 128, which is housed between the turbine and the pump.

In this variant, the epicyclic gear train comprises the same arrangement as that of FIG. 2 with the sun gear 130 carried by the hollow shaft of the turbine 124, the ring gear 132 carried by the shaft of the pump 1 18, and the carrier satellites 134 is carried by the vertical wall 135 of the housing 1 12.

The operation of this epicyclic train configuration is identical to that of FIG. 2 with a speed multiplier function between the pump and the turbine with a first multiplier speed ratio for the turbine with a rotational speed transmission between the carrier and the turbine. satellites, the ring gear, and the sun gear, and a speed reduction function between the turbine and the pump with a first reduction gear ratio between the sun gear, the planet carrier and the ring gear.

The main advantage of this variant lies in the distance of the pump and the turbine, which limits the heat exchange between the hot parts of the turbine and the pump, resulting in improved performance.

In the variant of Figure 5, the epicyclic train is also disposed between the pump and the turbine as for the variant of Figure 4 but with a particular arrangement of the epicyclic gear train 128.

In this configuration, the sun gear 130 is carried by the hollow shaft of the turbine 124, the ring 132 is carried by a vertical wall 135 of the housing 1 12, and the planet carrier 134 is carried by the shaft of the pump 1 18. This operation of this epicyclic train configuration is similar to that of FIG. 4 with a speed multiplier function between the pump and the turbine, with a second multiplier speed ratio for the turbine, when transmitting rotational speed between the turbine and the turbine. planet carriers, the crown, and the sun gear.

The variant of FIG. 6 differs from FIG. 2 only in the arrangement of the turbine 122, which is reversed, with the inlet 144 of the turbine which is situated on the side of the epicyclic gear train 128 and its output 146 on the side of the pump 1 1 6. This embodiment allows to juxtapose the large turbine diameter and the epicyclic train, facilitating a more compact design.

The operation of this configuration is identical to that of FIG. 2 with a speed multiplier function between the pump and the turbine with a first multiplier speed ratio for the turbine with a rotational speed transmission between the planet carrier, the turbine and the turbine. crown, and the sun gear, and a speed reduction function between the turbine and the pump with a first reduction gear ratio between the sun gear, the planet carrier and the ring gear.

In the variant of Figure 7, the epicyclic train 128 is also placed between the pump 1 1 6 and the turbine 122. In this embodiment, the pump 1 1 6 is housed between the train 128 and the connecting pulley 136 while the turbine is placed below this same train.

In the example of Figure 7, the pump shafts 1 18 and turbine 124 are separated from each other while being coaxial and in the extension of one another. The epicyclic gear train 128 is mounted between these two shafts with the ring gear 132 carried by the pump shaft 1 18, the sun gear 130 carried by the turbine shaft 124 and the planet carrier 134 carried by a fixed wall 150 of the housing 1 12.

The variant of Figure 8 differs from Figure 7 in that the ring 132 is carried by a fixed wall 150 of the housing 1 12, the sun gear 130 is carried by the turbine shaft 124 and the planet carrier 134 is worn by the pump shaft 1 18.

This variant of FIG. 7 also makes it possible to perform a speed multiplier function between the pump and the turbine with a second multiplier speed ratio for the turbine with a rotational speed transmission. between the planet carrier, the ring gear, and the sun gear, and a speed reduction function between the turbine and the pump with a first reduction gear ratio between the sun gear, the planet carrier and the crown

Claims

1) Turbopump comprising a fixed housing (12, 12 '; 1 12) having a kinetic pump (1 6, 1 1 6) with a pump rotor (14, 1 14) carried by a pump shaft (18, 18 ) and a turbine (22, 122) housing a turbine rotor (20, 120) carried by a turbine shaft (24, 124), characterized in that the pump shaft (18, 1 18) is separated from the turbine shaft (24, 124). turbine shaft (24, 124) and in that said turbopump comprises a speed variation device (26, 126) for generating a difference in rotational speed between the pump shaft (18, 1 18) and the turbine shaft (24, 124).

2) Turbopump according to claim 1, characterized in that said turbopump comprises a speed variation device (26, 126) for reducing the speed of rotation of the pump shaft (18, 1 18) relative to the shaft turbine (24, 124) or to multiply the rotational speed of the turbine shaft (24, 124) relative to the pump shaft (18, 1 18).

3) Turbopump according to claim 1 or 2, characterized in that the pump shafts (18) and turbine (24) are substantially parallel to each other.

4) Turbopump according to one of the preceding claims, characterized in that the speed variation device (26) comprises a toothed wheel (30) carried by the pump shaft (18) and a pinion (32) carried by the turbine shaft (24). 5) Turbopump according to claim 1 or 2, characterized in that the pump shafts (1 18) and turbine (124) are substantially coaxial with each other.

6) Turbopump according to claim 1 or 2, characterized in that the speed variation device comprises an epicyclic gear (128).

7) Turbopump according to claim 6, characterized in that the sun gear (130) of the epicyclic gear (128) is carried by the turbine shaft (124). 8) Turbopump according to one of claims 6 or 7, characterized in that the planet carrier (130) of the epicyclic gear (128) is carried by a fixed wall (135, 150) of the housing (1 12) of the turbopump . 9) Turbopump according to one of claims 6 or 7, characterized in that the planet carrier (130) of the epicyclic gear (128) is carried by the pump shaft (1 18).

10) Turbopump according to one of claims 6 to 9, characterized in that the ring (132) of the epicyclic gear (128) is carried by a fixed wall (135,

150) of the casing (1 12) of the turbopump.

1 1) Turbopump according to one of claims 6 to 9, characterized in that the ring (132) of the epicyclic gear (128) is carried by the pump shaft (1 18).

12) Turbopump according to one of claims 1 to 10, characterized in that it comprises a connecting pulley (34, 136) carried by the pump shaft (18, 1 18).

Turbocharger according to Claim 12, characterized in that the turbopump comprises a controlled-controlled coupling (36, 138) for connecting the connecting pulley (34, 136) and the pump shaft (18, 18). ). 14) Turbopump according to one of claims 1 to 1 1, characterized in that the turbopump comprises a speed variation means between the turbine shaft (24, 124) and a connecting pulley (34, 136).

15) Turbopump according to one of claims 1 to 14, characterized in that it comprises an electric machine driving the pump shaft (18, 1 18).

16) Application of a turbopump according to one of the preceding claims to a closed circuit, in particular of the Rankine or ORC (Organic Rankine Cycle) type.