JP2020532679A - Momentum-transporting turbopump with speed-variable device for closed circuits, especially Rankine cycle type, especially automobiles - Google Patents

Abstract

The present invention comprises a pump (16,116) having a pump rotor (14,114) supported by a pump shaft (18,118) and a turbine rotor (20,120) supported by a turbine shaft (24,124). The present invention relates to a turbo pump having a fixed casing (12, 12'; 112) including a turbine (22, 122) containing According to the present invention, the pump shaft (18,118) is separated from the turbine shaft (24,124), and the turbopump has a rotational speed between the pump shaft (18,118) and the turbine shaft (24,124). A speed fluctuation device (26,126) for generating a difference is provided.

Description

The present invention relates to closed circuits, especially Rankine cycle type turbopumps, especially momentum transport turbopumps for automobiles.
A momentum-transporting turbopump is understood to be an assembly consisting of a pump and a turbine.

According to the unique characteristics of the pump, the rotor supports a number of radial fins that form the impeller, which has the effect of causing the rotation and acceleration of the fluid in the liquid state. Through the effect of the rotation of the pump's impeller, the fluid is aspirated axially, then accelerated radially and expelled through the volute normally provided by the turbopump. A turbine connected to a pump on the same axis consists of a stator section that includes a stator assembly called a diffuser that is intended to convert the pressure of a vaporized fluid into kinetic energy. This kinetic energy is then converted into mechanical energy via a movable vane assembly of the rotor portion of the turbine. Turbine vanes consist of radial fins that allow expansion of the discharged fluid.
As is widely known, the Rankine cycle is a thermodynamic cycle in which heat from an external heat source is transferred to a closed loop containing the working fluid. During the cycle, the working fluid undergoes a phase change (liquid / vapor).
This type of cycle generally breaks down into a step in which the working fluid used in the liquid form is issentropically compressed and then a step in which the compressed liquid fluid is heated and vaporized by contact with a heat source. Will be done.
Then, in another step, the steam is expanded in an expansion device, and then in the final step, the expanded steam is cooled and condensed by contact with a cold source.

To carry out these various steps, the loop is swept by at least one pump for circulating and compressing the fluid in liquid form and a hot fluid for at least partial vaporization of the compressed fluid. It comprises a heat exchange evaporator and an expansion device for expanding this steam, such as a turbine that converts the energy of this steam into another energy such as mechanical or electrical energy, and a heat exchange condenser. .. To convert this vapor into a fluid in liquid form, the heat exchange condenser transfers the heat contained in the vapor to a cold source, typically outside air or a cooling water circuit, that sweeps the condenser.

In this type of circuit, the fluid used is generally water, but other types of fluids, such as organic fluids or mixtures of organic fluids, can also be used. This cycle is called the Organic Rankine Cycle (ORC).

As an example, the working fluid can be butane, ethanol, hydrofluorocarbons, ammonia, carbon dioxide and the like.

As is well known, hot fluids for vaporizing compressed fluids are liquid cooling media (from combustion engines, industrial processes, furnaces, etc.), hot gases resulting from combustion (exhaust gas from industrial processes and boilers, combustion engines or It can come from a variety of hot sources such as (such as exhaust fumes from turbines), heat flux from solar collectors or geothermal sources.

In general and in more detail, as described in WO 2013/046885 (Patent Document 1), the pump and turbine are combined and formed as an integral unit, thus forming a small turbopump.
The shaft of this turbopump, which is common to pumps and turbines, can be rotationally driven in different ways.
As described in French Patent Application Publication No. 2003227 (Patent Document 2), the shaft is formed by a pulley provided on the crankshaft of an internal combustion engine and another connecting pulley arranged on the shaft. It is connected to the crankshaft of the internal combustion engine by a belt that is laid over and controlled by a controlled coupler.

U.S. Patent Application Publication No. 2015/0064039 (Patent Document 3) discloses a turbopump in which a pump shaft and a turbine shaft are separate bodies. In this turbopump, a mechanical device such as a gear train is provided between the two shafts in order to change the direction of rotation of the turbine.
This device rotates the turbine in the first rotational direction and also operates the air conditioning circuit so that it operates as a turbine while associated with the pump that the turbo pump is equipped with for the Rankin cycle operation arrangement. Due to the arrangement, the turbine can be rotated in the opposite direction of rotation so that the turbine operates as a pump while it is disconnected from the pump of the turbo pump.

International Publication No. 2013/046885 French Patent Application Publication No. 30022779 U.S. Patent Application Publication No. 2015/0064039

All of these prior art turbopumps have some non-essential issues in the sense that the turbine operates at the same rotational speed as the pump. Therefore, the turbine speed can be low with respect to the optimum rotational speed, which can reduce its performance.

The present invention allows a turbine to have a significantly higher rotational speed than a combustion engine, while providing a turbopump in which the rotational speed of the pump is lower than the rotational speed of the turbine.
The pump efficiency is improved by using this appropriate speed, and the turbine efficiency is improved by increasing the speed.

Accordingly, the present invention relates to a turbopump comprising a momentum transport pump comprising a pump rotor supported by a pump shaft and a fixed casing including a turbine accommodating a turbine rotor supported by the turbine shaft. The pump shaft is separated from the turbine shaft, and the turbo pump includes a speed fluctuation device for generating a rotational speed difference between the pump shaft and the turbine shaft.

According to one embodiment of the present invention, the turbopump is a speed variable device for reducing the rotational speed of the pump shaft with respect to the turbine shaft or increasing the rotational speed of the turbine shaft with respect to the pump shaft. To be equipped.

Advantageously, the pump shaft and turbine shaft are substantially parallel to each other.
According to one aspect, the speed variable device comprises a gear supported by a pump shaft and a pinion supported by a turbine shaft.
According to one embodiment, the pump and turbine shafts are substantially coaxial with each other.
According to the feature, the speed variable device includes a planetary gear mechanism.
Advantageously, the sun gear of the planetary gear mechanism is supported by the turbine shaft.
Advantageously, the planetary gear carrier of the planetary gear mechanism is supported by the fixed wall of the turbopump casing.
Alternatively, the planetary gear carrier of the planetary gear mechanism is supported by a pump shaft.
According to one embodiment, the crown of the planetary gear mechanism is supported by a fixed wall in the casing of the turbopump.
Alternatively, the crown of the planetary gear mechanism is supported by the pump shaft.
According to one embodiment, a connecting pulley supported by a pump shaft is provided.
According to the features, the turbopump comprises a controlled coupler for the connection of the coupling pulley and the pump shaft.
According to one aspect, the turbopump comprises a speed variable device between the turbine shaft and the connecting pulley.
Advantageously, it comprises an electric motor that drives the pump shaft.

Furthermore, the present invention relates to the application of turbopumps based on one of the above features to closed loops, especially Rankine or ORC (Organic Rankine Cycle) closed loops.

Other features and advantages of the present invention will become apparent from reading the following description given as a non-limiting example with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an embodiment of a turbo pump according to the present invention. FIG. 2 is a cross-sectional view of another embodiment of the turbopump according to the present invention. It is sectional drawing of the different modification of FIG. It is sectional drawing of the different modification of FIG. It is sectional drawing of the different modification of FIG. It is sectional drawing of the different modification of FIG. It is sectional drawing of the different modification of FIG. It is sectional drawing of the different modification of FIG.

FIG. 1 shows a turbo pump 10 for a closed loop, especially for the Rankine cycle type, especially for automobiles.

Here, the turbine pump 10, which is a momentum transport type turbo pump, is a fixed casing that is supported by a pump shaft 18 and houses a rotating portion 14 (or rotor) of a means called a pump that is intended to circulate and compress the fluid 16. 12 and another fixed casing 12'supporting the turbine shaft 24 and accommodating a rotating portion 20 (or rotor) of means intended to inflate the compressed fluid 22, called a turbine.
In the example of FIG. 1, according to a particular feature of the turbopump, the two shafts 18, 24 are separated from each other, and they are arranged parallel to each other and vertically to each other.
As can be seen in detail from FIG. 1, the two shafts are separated (or distinguished) from each other, and they allow a speed variation device 26 to generate a rotational speed difference between the pump shaft and the turbine shaft. Are connected to each other by.
More specifically, the purpose of the speed variable device is to increase the rotational speed between the pump shaft and the turbine shaft when the pump shaft gives a rotational speed pulse, as described in detail below. That is, or if the turbine shaft produces a rotational speed, the rotational speed between the turbine and the pump is reduced.

The speed variable device comprises a gear train 28 with a large diameter gear 30 supported by a pump shaft 18, which cooperates with a pinion 32 having a smaller diameter than the gear supported by the turbine shaft 24. .. Advantageously, the gear and the pinion are placed in the same vertical plane.
The diameter difference between the gear and the pinion thus makes it possible to achieve a gear ratio between the two axes, which gear ratio is preferably in the range between 2 and 6 in the context of the present invention. It is in.
Therefore, in order to obtain the desired gear ratio between the two shafts 18, 24, the diameters of the gear and pinion need to be exactly parameterized to achieve these ratios.

The turbopump also includes a coupling pulley 34 that is rotationally connected to the pump shaft 18 via a controlled coupler 36, which is an electromagnetic clutch here.
The pulley is rotationally controlled by a band that is itself closed, such as a chain or fastening belt 38.
Advantageously, this band is connected to a crankshaft pulley that is rotationally connected to the crankshaft of an internal combustion engine (not shown).

A variant consists of replacing mechanical links (pulleys and electromagnetic clutches) with a generator to form a turbopump generator.

Turbo pumps such as those described above can be used in many fields such as petroleum, aviation, and automobile fields.

Examples of applications of this turbopump are found more specifically in closed loops, especially in the Rankine cycle closed loop 40 as illustrated in FIG.

This closed Rankine cycle loop is advantageously of the ORC (Organic Rankine Cycle) type and uses an organic working fluid or organic fluid mixture such as butane, ethanol, hydrofluorocarbon.

It is also understood that closed loops can operate with fluids such as ammonia, water and carbon dioxide.

Therefore, the outlet 42 of the pump 16 is connected to the inlet 44 of the heat exchanger 46 called an evaporator, the working fluid compressed by the pump flows through the evaporator, and the working fluid is vaporized in the form of compressed steam by the evaporator. Reach the outlet 48 of the vessel.
The evaporator is also traversed by a heat source 50 in the form of a liquid or gas, which heat can be applied to the working fluid. This hot source allows the vaporization of the fluid. Hot sources are from combustion engines and industrial processes, cooling media from furnaces, hot gases from combustion (such as exhaust from combustion engines, industrial processes, exhaust from boilers or turbines), solar collectors or geothermal sources. It can come from various hot sources such as heat flux.
The evaporator outlet is connected to the inlet 52 of the turbine 22 to receive a working fluid in the form of high pressure compressed steam, which fluid exits the turbine through the outlet 54 of the turbine in the form of low pressure expanded steam.
The outlet of the turbine is connected to the cooling heat exchanger 58, that is, the inlet 56 of the condenser. The condenser makes it possible to convert the received low pressure expansion vapor into a low pressure liquid fluid in order to supply the low pressure liquid fluid to the inlet of the pump. The condenser is swept by a cold source, which is generally a stream of ambient air or cooling water, to cool the expanded vapor so that it condenses into a liquid.

Of course, the various elements of the loop are connected to each other by fluid circulation lines that allow them to be connected continuously.

Therefore, the internal combustion engine is operable during the closed loop operation and during the start phase, and the pump 16 of the turbopump requires start. Therefore, the shaft 18 is connected to the connecting pulley 34 of the turbo pump by the clutch 36. Next, the rotational movement of the crankshaft is transmitted to the connecting pulley 34 via the connecting belt 38. This rotational motion is then retransmitted to the pump shaft 38 and the pump rotor.
During this rotational movement of the pump shaft, which is a rotational movement generating element, the gear 30 meshes with the pinion 32. Considering the gear ratio resulting from the difference in diameter between the gear and the pinion, the turbine shaft 24 rotates at a higher speed than the pump shaft, and therefore the turbine rotates at a higher speed than the pump.
Therefore, the speed variable device 26 performs a speed multiplying function between the pump and the turbine.

After this start-up stage, the turbine produces more power than is consumed by the pump, and thus the turbine becomes a rotational motion generating factor for the loss due to the pump.

The internal combustion engine is still operable, and the shaft 18 is connected to the pulley 34 of the turbopump by a clutch 36.
The power generated by the turbine 22 is transmitted to the pinion 32, which transmits the power to the gear 30, and then to the pulley 34 of the turbo pump. The power of the pulley 34 is subsequently transmitted by the belt 38 to the crankshaft pulley, which gives power to the crankshaft and thus to the internal combustion engine. This can support the work required by the engine and thus reduce the fuel consumption of the engine.
In this configuration, the speed variable device 26 acts as a speed reducer between the turbine shaft and the pump shaft.
In fact, contrary to the starting stage, the rotational motion is transmitted from the pinion to the gears. Given the gear ratio, the gears, and thus the pump, rotate at a slower speed than the pinion of the turbine shaft. Therefore, turbines can have much higher rotational speeds than engines and pumps, which is favorable for turbine efficiency.

FIG. 2 is a diagram showing another embodiment of the turbo pump according to the present invention.

The turbopump 110, which is also a momentum transport turbopump, includes a fixed casing 112 that houses the rotor 114 of the pump 116 supported by the pump shaft 118 and the rotor 120 of the turbine 122 supported by the turbine shaft 124.
In the example of FIG. 2, the pump shaft and the turbine shaft are separated from each other, but are aligned with each other, preferably coaxially.
Advantageously, the pump shaft 118 runs coaxially through the turbine shaft 124 and exits beyond the turbine. Therefore, the turbine shaft 124 is hollow.

As in the example of FIG. 1, the two shafts are connected to each other by the speed variable device 126.

This device can also generate a rotational speed difference between the pump shaft and the turbine shaft.
Similar to the example described in FIG. 1, the purpose of the speed variable device is between the pump shaft and the turbine shaft when the pump shaft gives a rotational speed pulse, as detailed in the rest of the specification. It is to increase the rotational speed of the turbine and to decrease the rotational speed between the turbine and the pump when the turbine shaft generates the rotational speed.
The speed changer includes a planetary gear mechanism 128 in which the sun gear 130 is supported by the hollow shaft 124 of the turbine, the crown 132 of which is supported by the pump shaft 118, and the planetary gear carrier 134 of which is supported by the vertical wall 135 of the casing 112. Be supported.
The turbopump also comprises a coupling pulley 136 that is rotationally connected to the pump shaft 118 via an electromagnetic clutch type controlled coupler 138 that is rotationally controlled by a band that itself is closed, such as a chain or coupling belt 140. ing.
This band is advantageously connected to a crankshaft pulley that is rotationally coupled to the crankshaft of an internal combustion engine (not shown).

As in the example of FIG. 1, applications of this turbopump are found more specifically in closed loops, especially in Rankine cycle closed loops.
Therefore, the outlet 142 of the pump 116 is connected to the inlet of the evaporator through which the working fluid compressed by the pump flows, and the outlet of the evaporator is connected to the inlet 144 of the turbine 122. A working fluid in the form of high pressure compressed steam is supplied through the inlet 144 of the turbine 122, and this fluid exits the turbine through the outlet 146 in the form of low pressure expanded steam.
The turbine outlet is connected to the inlet of the condenser, which can convert the received low pressure expanded vapor into a low pressure liquid fluid so as to supply the low pressure liquid fluid to the inlet 148 of the pump.

The operation of this turbo pump is the same as that of the turbo pump of FIG.

Therefore, during the start phase of the closed loop, the internal combustion engine is operable and the pump 116 of the turbopump requires a start. Therefore, the shaft 118 is connected to the connecting pulley 136 of the turbo pump by the clutch 138. The rotational movement of the crankshaft is then transmitted to the connecting pulley via the connecting belt 140. This rotational motion is then retransmitted to the pump shaft and pump rotor, as well as the crown 132 of the planetary gear mechanism 128.
During the rotational movement of the crown, which is a rotational movement generating element, the crown meshes with a fixed planetary gear carrier. The rotational motion of the planetary gears of this planetary gear carrier is transmitted to the sun gear 130 and then to the turbine shaft.
In this configuration, the planetary gear mechanism has a gear ratio that allows the sun gear speed to be increased relative to the crown. Therefore, the turbine rotates at a higher speed than the pump.
The planetary gear mechanism 128 is therefore a function of the speed multiplier between the pump and the turbine, which comprises a rotational speed transmission mechanism between the crown, the planetary gear carrier and the sun gear and has a first speed multiplier ratio to the turbine. Fulfill.
After this start-up stage, the turbine produces more power than is consumed by the pump, and thus the turbine becomes a rotational motion generating factor for the loss due to the pump.
The internal combustion engine is still operable, and the shaft 118 is connected to the pulley 136 of the turbopump by a clutch 138.
The power generated by the turbine 122 is transmitted to the sun gear 130, which transmits power to the crown 132 via the planetary gear carrier 134. The power of the crown is transmitted to the turbine shaft and the pulley 136 of the turbo pump.
The power of the pulley is then transmitted by the belt 140 to the crankshaft pulley, which gives power to the crankshaft and thus to the internal combustion engine.
In this configuration, the speed variable device 126 acts as a reducer between the turbine shaft and the pump shaft, having a first reduction ratio to the pump, with rotational transmission between the sun gear, planetary gear carrier and crown. To do. The advantage of this configuration is that it allows the turbine to have a much higher rotational speed than the engine and pump, which favors turbine efficiency.

The modified example of FIG. 3 includes the same elements as in FIG. 2, but has a planetary gear mechanism 128 having a specific configuration.
In this configuration, the sun gear 130 is supported by the hollow shaft 124 of the turbine, the crown 132 is supported by the vertical wall 135 of the casing 112, and the planetary gear carrier 134 is supported by the pump shaft 118.
The operation of the configuration of this planetary gear mechanism is similar to that of FIG. 2 having a speed multiplying function between the pump and the turbine in response to the transmission of rotational speed between the planetary gear carrier, crown and sun gear, and the turbine. Has a second speed multiplication ratio for.

A variant of FIG. 4 also comprises the same elements as FIG. 2 or 3, but with a particular arrangement of planetary gear mechanisms 128 housed between the turbine and the pump.
In this variant, the planetary gear mechanisms include a sun gear 130 supported by a hollow shaft 124 of the turbine, a crown 132 supported by a pump shaft 118, and a planetary gear carrier 134 supported by a vertical wall 135 of the casing 112. Has the same arrangement as in FIG.
The operation of the configuration of this planetary gear mechanism is the speed multiplication function between the pump and the turbine at the first speed multiplication ratio for the turbine, which has rotational speed transmission between the planetary gear carrier, crown and sun gear. And the same as that of FIG. 2 with a speed reduction function between the turbine and the pump having a first speed reduction ratio between the sun gear, the planetary gear carrier and the crown.
The main advantage of this variant is the distance between the pump and the turbine, which can limit the heat exchange between the hot part of the turbine and the hot part of the pump, resulting in efficiency. Is improved.

Also in the modified example of FIG. 5, the planetary gear mechanism is arranged between the pipe and the turbine as in the modified example of FIG. 4, but has a specific arrangement of the planetary gear mechanism 128.
In this configuration, the sun gear 130 is supported by the hollow shaft 124 of the turbine, the crown 132 is supported by the vertical wall 135 of the casing 112, and the planetary gear carrier 134 is supported by the pump shaft 118.
The operation of the configuration of this planetary gear mechanism is similar to that of FIG. 4, which has a speed multiplying function between the pump and the turbine in response to rotational speed transmission between the planetary gear carrier, crown and sun gear. It has a second speed multiplication ratio for the turbine.

A variant of FIG. 6 differs from FIG. 2 only in an inverted turbine 122 arrangement where the turbine inlet 144 is on the planetary gear mechanism 128 side and the outlet 146 is on the pump 116 side. Embodiments of this variant allow for juxtaposition of large turbine diameters and planetary gear mechanisms, thus providing a more compact design.
The operation of this configuration is the speed-up function between the pump and the turbine, which has a first speed-boosting ratio for the turbine by rotational speed transmission between the planetary gear carrier, crown and sun gears, and the sun gears, planets. It is identical to that of FIG. 2 with a speed reduction function between the turbine and the pump having the first reduction ratio between the gear carrier and the crown.

Also in the modified example of FIG. 7, the planetary gear mechanism 128 is arranged between the pump 116 and the turbine 122. In this variant, the pump 116 is housed between the gear mechanism 128 and the connecting pulley 136, while the turbine is located beneath this gear mechanism.
In the example of FIG. 7, the pump shaft 118 and the turbine shaft 124 are separated from each other, but are coaxial and arranged in a line with each other. The planetary gear mechanism 128 comprises a crown 132 supported by a pump shaft 118, a sun gear 130 supported by a turbine shaft 124, and a planetary gear carrier 134 supported by a fixed wall 150 of the casing 112. It is mounted between the two shafts.

A modification of FIG. 8 differs from FIG. 7 in that the crown 132 is supported by the fixed wall 150 of the casing 112, the sun gear 130 is supported by the turbine shaft 124, and the planetary gear carrier 134 is supported by the pump shaft 118.
This variant of FIG. 7 also has a speed multiplying function between the pump and the turbine having a second speed multiplying ratio for the turbine by rotational speed transmission between the planetary gear carrier, crown and sun gear, and the sun gear. It makes it possible to achieve a speed reduction function between the turbine and the pump, which has a first speed reduction ratio between the planetary gear carrier and the crown.

Claims (16)

A momentum transport pump (16,116) with a pump rotor (14,114) supported by a pump shaft (18,118) and a turbine rotor (20,120) supported by a turbine shaft (24,124). In a turbopump with a fixed casing (12,12'; 112) including a turbine (22,122) to accommodate.
The pump shaft (18,118) is separated from the turbine shaft (24,124), and the turbopump has a rotational speed difference between the pump shaft (18,118) and the turbine shaft (24,124). A turbo pump characterized by being provided with a speed fluctuation device (26,126) for generating the above. The turbopump either reduces the rotational speed of the pump shaft (18,118) relative to the turbine shaft (24,124) or the turbine shaft (24, 118) relative to the pump shaft (18,118). The turbo pump according to claim 1, further comprising a speed fluctuation device (26,126) for increasing the rotation speed of 124). The turbo pump according to claim 1 or 2, wherein the pump shaft (18) and the turbine shaft (24) are substantially parallel to each other. The speed changer (26) comprises a gear (30) supported by the pump shaft (18) and a pinion (32) supported by the turbine shaft (24). The turbo pump according to any one of 1 to 3. The turbo pump according to claim 1 or 2, wherein the pump shaft (118) and the turbine shaft (124) are substantially coaxial with each other. The turbo pump according to claim 1 or 2, wherein the speed fluctuation device includes a planetary gear mechanism (128). The turbo pump according to claim 6, wherein the sun gear (130) of the planetary gear mechanism (128) is supported by the turbine shaft (124). 6. Or 7, claim 6, wherein the planetary gear carrier (134) of the planetary gear mechanism (128) is supported by a fixed wall (135, 150) of the casing (112) of the turbopump. Turbo pump. The turbo pump according to claim 6 or 7, wherein the planetary gear carrier (134) of the planetary gear mechanism (128) is supported by the pump shaft (118). One of claims 6 to 9, wherein the crown (132) of the planetary gear mechanism (128) is supported by a fixed wall (135, 150) of the casing (112) of the turbo pump. The turbo pump described in. The turbo pump according to any one of claims 6 to 9, wherein the crown (132) of the planetary gear mechanism (128) is supported by the pump shaft (118). The turbo pump according to any one of claims 1 to 10, further comprising a connecting pulley (34, 136) supported by the pump shaft (18, 118). 12. The twelfth aspect of claim 12, wherein the turbopump includes a controlled coupler (36,138) for connecting the coupling pulley (34,136) to the pump shaft (18,118). Turbo pump. The turbo pump according to any one of claims 1 to 11, wherein the turbo pump includes a speed fluctuation device between the turbine shaft (24, 124) and the connecting pulley (34, 136). .. The turbo pump according to any one of claims 1 to 14, further comprising an electric motor for driving the pump shafts (18, 118). The application of the turbo pump according to any one of claims 1 to 15 to a closed loop, particularly a Rankine type or ORC (organic Rankine cycle) type closed loop.

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