WO2007090420A1

WO2007090420A1 - Thermodynamic flow machine

Info

Publication number: WO2007090420A1
Application number: PCT/EP2006/001111
Authority: WO
Inventors: Klaus-Peter Renner
Original assignee: Klaus-Peter Renner
Priority date: 2006-02-08
Filing date: 2006-02-08
Publication date: 2007-08-16

Abstract

In a method for operating a thermodynamic flow machine with a gas as the working agent and on the basis of the Brayton cycle or the inverse Brayton cycle, the gas is compressed and expanded in the interior of a body which rotates about a rotation axis (4), and the compression and expansion work is produced by flow in gas columns in the centrifugal force field of the rotating body in that, in the rotating body, the gas is carried in at least one channel (2) which not only forces the gas to flow from areas close to the axis to areas remote from the axis of the body which can rotate, thus resulting in compression, but also forces the gas to flow from areas remote from the axis to areas close to the axis of the rotating body, thus producing expansion. The Coriolis forces which occur in the at least one channel (2) during the radial compression and expansion flow of the gas are in this case completely absorbed by a side wall (24) which bounds the channel (2) in the tangential direction.

Description

Thermodynamic turbomachine

The invention relates to a thermodynamic fluid machine, which is operated with a gas as a working fluid.

Conventional flow heat engines (e.g., gas turbines) suffer particularly from aerodynamic losses in both the compressor and expansion stages. Although these losses are relatively low in relation to the respective compression and expansion performance, but high in comparison to the usable work, the difference between compression and expansion performance, and represent a significant limitation of the achievable efficiency.

Conventional heat pumps often use a working medium with phase transitions in closed circuits. Because of the necessary heat exchangers, ancillaries and the temperature range predetermined by the working fluid, the theoretically possible efficiency is far from being achieved.

An approach that seeks to exploit the centrifugal force for compression and expansion of the working gas in support of the so-called. Lorin drive is described in the published patent application DE 199 19 616 A1 in the embodiment of FIG. In practice, however, only low efficiencies result in this embodiment, and especially at low flow rates of the working gas, the construction shown is impracticable.

An object of the present invention is to make the compression and expansion process of a turbomachine almost loss-free and to subject only the usable work the usual conversion losses of flow work in mechanical work. Another object of this invention is to maintain the high efficiency in a wide performance range from part load to full load.

This object is achieved by the method according to claim 1 and the device according to claim 13 according to the invention.

Advantageous embodiments are described in the subclaims. According to the invention, the principle of hydrostatic compression and expansion, as occurs, for example, in the atmosphere, is technically realized in a thermodynamic machine, wherein the centrifugal force is used instead of gravity, in small dimensions necessary for thermodynamic turbomachines temperature and pressure differences to reach.

The compression and expansion takes place in a rotating body by flow against a positive or negative pressure gradient in adiabatically layered gas columns almost lossless, the pressure gradients are generated in the hydrostatic equilibrium gas columns by centrifugal forces. In the rotating body, the following parts of the cycle process take place: hydrostatic compression, high-pressure phase and hydrostatic relaxation. The existing from Restentspannung or residual compression mechanical active power can be implemented outside of the rotating body by means of fans or turbines. The cycle is closed on low temperature side either inside the rotating body or by the external gaseous environment as a heat reservoir.

Further details, features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

1 shows a schematic diagram of the method according to the invention in a closed circuit in the centrifugal force field,

2 shows a schematic diagram of the method according to the invention in an open circuit in the centrifugal force field,

3 shows a state diagram which explains the circuits according to the invention,

4a to c show a longitudinal sectional view and two cross-sectional views of an embodiment of an open turbomachine according to the invention, and 5 shows a longitudinal sectional view of another open turbomachine according to the invention.

The underlying principle will be described with reference to FIGS. 1 and 2. Fig. 1 shows a closed pipe system in a rotating body, for example mounted in a rotor. In a channel 2, the working gas circulates as indicated by the arrows. The rotation axis 4 is perpendicular to the plane of the drawing and intersects it at x. The radial arrows represent the radially increasing centrifugal forces. In the centrifugal force field, even without flow, a radially increasing hydrostatic pressure distribution in the working gas sets in. If now a flow is generated in the pipe system, for example by a fan (shown schematically at L), an adiabatic temperature increase arises after a short time between A and B, likewise a temperature drop between C and D. Without heat exchange via the walls of the channel 2 a static, only depending on the distance from the axis of rotation and radially increasing temperature distribution sets. Temperature gradient and centrifugal acceleration are linearly related for a given gas type (dT / dr ~ ω ² ή.) The temperature differences (BA or DC) depend only on the rotor speed, the distances to the axis of rotation 4 and the gas used, but not of the (from 0 different) flow rate of the working gas.

The flow of gas in the rotating reference system creates in the gas Coriolis forces acting on the walls of the pipe. As a result, on the way from A to B, a torque is generated counter to the direction of rotation, on the way from C to D, a torque in the direction of rotation. Both torques cancel each other out completely, but lead to tensions or twists in the rotating body. From an energy point of view, the release of Coriolis in the rotating body during relaxation (from C to D) is immediately and losslessly plugged into the Coriolis power required for compression (from A to B).

Fig. 2 shows an open system with the difference from Fig. 1 that the working gas is connected through openings, ie inlet 6 and outlet 8, in the rotating body at A and D with the non-rotating environment. The circuit is thus closed by externally mounted fan (not shown here). The system operates as a chiller when heat is removed from the environment at the low temperature level (at D) or as a heat engine when heat is released to the environment at a high temperature level in a thin channel section 10 (between B and G). FIG. 3 illustrates the state diagram of a gas packet that traverses the representations of FIG. 1 or FIG. 2. The gas package is compressed by the fan from the initial pressure and temperature (P1, T1) while working on P2, T2 at the inlet 6 of the rotating body (A). Then the further adiabatic compression takes place in the channel 2 by flow in the hydrostatic gas column up to the pressure and temperature maximum (P3, T3) at B. The gas packet now flows at constant pressure in the channel section 10 to C and releases heat. After cooling down around T4-T3, the relaxation in the gas column against the centrifugal force to the outlet 8 begins at D. During the relaxation, the gas package again passes through the same temperature difference as in the compression (T3-T2 = T4-T5), provided the radial Paths of the two gas columns are the same. In the closed system (Figure 1), the gas at D takes up heat again (from T5 to T1). In the open system (Figure 2), the gas exits the rotating body at initial pressure P1 by the amount T1-T5. The necessary compaction pressure through the fan (P2-P1) is adjusted automatically so that the flow losses and the necessary thermodynamic work output of the heat / chiller are provided. For the theoretical efficiency of the chiller after the Brayton cycle:

For the theoretical efficiency of the heat engine, the following applies after the Brayton cycle: _Whe i _Z / W _mech = T4 / (T4-T5).

The system works as a heat engine when heat is introduced into the system at high temperature levels (between B and C) and released into the environment at low temperature levels (at A). In this case, the state diagram in Fig. 3 is reversed. The gas package starts at A with initial pressure and temperature P1, T5. From A to B, the adiabatic compression in channel 2 takes place through flow in the hydrostatic gas column to P3, T4 at B. The gas package now flows at constant pressure to C and absorbs heat from an external heat source. After heating up by T3-T4, the relaxation in the gas column begins against the centrifugal force to D. During the relaxation, the gas package runs through the same temperature difference as in the compression (T3-T2 = T.4- T5), assuming the radial paths of the both gas columns are the same. Between D and A, the residual relaxation takes place on P1, T1 with delivery of work in a turbine. The waste heat T1-T5 is released into the environment. The corresponding theoretical efficiency is: W _meCh / W _he i _z = (T4-T5) / T4. .

The lossless compression and relaxation means a significant improvement over conventional thermodynamic turbomachinery.

By using the gaseous environment as the heat reservoir of the open system no heat exchange losses occur on the low temperature side.

The speed can be used to optimally adjust the machine to the required temperature levels.

The performance of the device as a heat pump or chiller can be controlled over the mass flow generated by the fan over a wide range. Even with low mass flows, a high level of efficiency is to be expected since the compressor only has to apply active power and the rotating body only has to compensate for bearing losses.

The fan or the turbine transmits only the active work, i. The turbine efficiency is a simple factor in the overall efficiency.

In a closed system design using heavy monatomic gases, the necessary speed can be substantially reduced.

An embodiment of an open system according to the invention is shown in FIGS. 4a to 4c in a longitudinal section and two cross sections. The thermodynamic fluid machine consists of a symmetrical rotatable body having an outer drum, which consists of several successive sections 12, 14, 16, 18 and 20. The end portions 12 and 20 thereby form a cylindrical shape, wherein they are relatively close to the axis of rotation 4, while the portions 14 and 18 form the shape of a truncated cone, which opens to a central portion 16, which in turn takes the form of a cylinder of larger radius forms around the axis of rotation 4. The central portion 16 is thus also referred to as a lateral surface portion of the rotatable body. The turbomachine also has an inner drum 22, which is arranged in the region of the lateral surface portion 16 and extends close to this. In the interior of the body, in turn, channels 2 are formed, which are separated from one another in the tangential direction by side walls 24. They open at each end face in a concentric circular opening (inlet 6 and outlet 8) about the axis of rotation 4. The opening diameter should be as small as possible, for example 25% of the diameter of the rotating body does not exceed. In the area between the inner drum 22 and the lateral surface portion 16 of the outer drum of the thin channel portion 10 is formed, in which the gas has a high temperature and high pressure during operation. It is essential that the radial extent of the channel sections 10 between the inner drum 22 and lateral surface section 16 (see section YY) is kept as low as possible, since at maximum distance from the axis of rotation 4 both pressure gradient and temperature gradient are maximal. Large dimensions reduce the efficiency.

The essential for the operating principle side walls 24 serve to receive the occurring due to the radial gas flow component Coriolis forces and must therefore be performed mechanically stable. The beginning and end portions of the side walls 24 may be aerodynamically shaped. Only in areas in which no or only a small Coriolis force occurs, the side walls 24 may be interrupted, so for example in the region of the channel portion 10th

All of the radially extending structures of this embodiment are made of as few thermally conductive and high strength materials as possible, e.g. Fiber composites.

The rotating body can be driven by a conventional motor, such as an electric motor, which controls the speed. The shaft shown in the region of the axis of rotation 4 is not absolutely necessary, but can serve as storage. Not shown are fans or turbines, which are attached to the inlet 6 or outlet 8 and implement the mechanical power. The end sections 12, 20 of the outer drum can also be used for storage, also as an airtight connection for fans or turbine. Alternatively, an impeller may be installed between axis 4 and the outer sections 1220 of the outer drum for the fan or turbine function. The embodiment of the invention shown here as an air-to-air heat pump uses the air as a heat source and working gas. At the inlet, a fan (not shown) is mounted as a drive. The heat is dissipated via the rotating lateral surface portion 16, which should consist of good heat conducting material, to the body surrounding air layer, which is used directly as heating air.

An embodiment according to the invention as an air-water heat pump (not shown) arises from the same arrangement in that the rotating body is surrounded by a heat exchanger, e.g. a tube winding around the lateral surface portion 16, in which the liquid circulates. The heat is mainly transported by heat conduction in the smallest possible air gap between lateral surface portion 16 and heat exchanger.

For embodiments as a heat engine, in principle any external heat source can be used which supplies heat to the lateral surface section 16 at the selected temperature. However, the use of solar energy as a heat source is particularly favorable. With the help of reflectors, the radiation can be focused directly on the lateral surface portion 16, without detours through other heat exchangers. In steady state operation, a turbine (not shown) attached to the outlet 8 converts the residual pressure of the working gas into available shaft power.

Another embodiment of the invention as a heat engine uses the internal combustion with air as the working gas. The fuel is passed approximately through a separate supply channel (not shown) in the region of the axis of rotation 4 of the rotating body and a radially extending supply line (not shown) and admixed with the air in the channel section 10. The combustion and thus the heat supply thus takes place in the pressure maximum. In this design, the body is best thermally insulated, so that here, too, a nearly ideal implementation of the thermodynamic principle is achieved. To reduce losses, the body may be stored in an evacuated housing.

Another embodiment according to the invention is shown in FIG. This embodiment combines a heat pump and a heat engine. From the left, the working gas enters a rotating body and is compressed. In the temperature and pressure maximum at the highest peripheral speed in a first thin channel portion 10a adjacent to a first lateral surface portion 16a is in turn externally or by combustion heat supplied (heat supply devices not shown). After partial relaxation, heat is released at a lower temperature level in the region of a second thin channel section 10b via a second good heat-conducting lateral surface section 16b.

In this embodiment, the influence of heating and cooling on the residual pressure at the outlet 8 cancel, a further mechanical drive source for conveying the working gas is not needed. This arrangement represents a thermally driven heat pump or chiller, again at the highest possible efficiency. The body only needs to be kept at speed by a suitable drive, but with low power consumption to overcome the friction.

It is clear that various geometrical configurations are conceivable, which deviate from the previously mentioned examples, but nevertheless fall under the inventive concept, as defined by the appended claims. In addition, a turbine can also be coupled to the inlet, which then acts as a "suction turbine", and a fan can also be coupled to the outlet, which then sucks the gas out of the rotating body, which makes sense if one and the same machine So both heat / chiller and used as a heat engine and aerodynamic reasons, the flow direction is maintained.

In the refrigeration and heat engineering, the present invention provides considerable energy savings potential through better efficiencies. As a heat engine, possible applications include e.g. in power plants, in particular solar power plants, when using low temperature differences for power generation, in hybrid drives in conjunction with internal combustion. Due to the small number of parts, a cost-effective production in all applications possible.

Claims

claims

1. A method for operating a thermodynamic fluid machine with a gas as a working fluid on the basis of the Brayton cycle or the reverse Brayton cycle, wherein the gas is compressed and relaxed inside a rotating about a rotation axis (4) body and the compression and relaxation work Flow in gas columns in the centrifugal force field of the rotating body is carried out by the gas in the rotating body in at least one channel (2), which both a flow of gas from near-axis regions to off-axis portions of the rotating body, whereby the compression is effected, as well a flow of the gas from off-axis areas to near-axis areas of the rotating body, whereby the relaxation is effected forces,

characterized in that

the Coriolis forces occurring in the radial compression or expansion flow of the gas in the at least one channel (2) are completely absorbed by a side wall (24) bounding the channel (2) in the tangential direction.

2. The method according to claim 1, characterized in that a gas with the lowest possible specific heat capacity, such as xenon, is used.

3. The method according to claim 1 or 2, characterized in that in a parallel to a lateral surface portion (16) of the rotating body extending portion (10) of the at least one channel (2) takes place in the high pressure phase of the gas heat exchange.

4. The method according to claim 3, characterized in that the environment of the lateral surface portion (16) is heated by the heat exchange.

5. The method according to claim 3, characterized in that the Mantelflä- chenabschnitt (16) by the heat exchange additional heat from the environment is supplied.

6. The method according to claim 3, characterized in that the heat exchange takes place in the high pressure phase of the gas by internal combustion of a fuel.

7. The method according to claim 5 or 6, characterized in that in a first, parallel to a first lateral surface portion (16a) extending portion (10a) of the channel (2) the gas in the high pressure phase by heat exchange or by internal combustion of a fuel additional heat is supplied, and that in a second, parallel to a second, closer to the axis arranged lateral surface portion (16b) extending portion (10b) of the channel (2), the environment of the second lateral surface portion (16b) is heated by heat exchange.

8. The method according to any one of claims 5 to 7, characterized in that the gas is passed via a near-axis outlet (8) of the channel (2) to a turbine, by which the residual pressure of the gas is converted into mechanical power.

9. The method according to claim 1 or 2, characterized in that takes place in a parallel and close to the axis of the rotating body extending portion of the at least one channel (2) in the low pressure phase of the gas heat exchange with the environment.

10. The method according to claim 9, characterized in that the environment of the parallel and arranged close to the axis portion of the channel (2) is cooled by the heat exchange.

11. The method according to claim 9, characterized in that the heat exchange in the low pressure phase of the gas by mass exchange via a near-axis inlet (6) and outlet (8) of the channel (2) to the environment.

12. The method according to any one of the preceding claims, characterized in that the gas is conveyed by means of a compressor via a near-axis inlet (6) in the channel (2).

A thermodynamic turbomachine comprising a gas acting as a working fluid and a body rotatable about an axis of rotation (4) having at least one channel (2) into which the gas is insertable and which is oriented to rotate upon rotation the gas from near-axis regions to achsfemen areas of the rotatable body, whereby a compression is effected, as well as a flow of the gas from off-axis regions to near-axis regions of the rotatable body, whereby a relaxation is caused to force

characterized in that

the at least one channel (2) is delimited in the tangential direction by a side wall (24) which serves to completely accommodate the Coriolis forces arising during the radial compression or expansion flow of the gas.

14. Thermodynamic turbomachine according to claim 13, characterized in that the gas, for example xenon, has the lowest possible specific heat capacity.

15. Thermodynamic turbomachine according to claim 13 or 14, characterized in that the rotatable body has a lateral surface portion (16) and a thin portion (10) of the at least one channel (2) in the region of the lateral surface portion (16), in the gas in the High pressure phase is performed.

16. Thermodynamic turbomachine according to claim 15, characterized in that the lateral surface section (16) has a good thermal conductivity.

17. Thermodynamic turbomachine according to claim 16, characterized in that a heat exchanger is arranged around the lateral surface section (16).

18. Thermodynamic turbomachine according to claim 16, characterized in that in the region of the axis of rotation (4) a supply channel for fuel is provided, which is connected via a radially extending supply line with the thin portion (10) of the channel.

19. Thermodynamic turbomachine according to one of claims 16 to 18, characterized in that the rotatable body has a first, parallel to a first lateral surface portion (16 a) extending portion (10 a) of the channel (2), which is for the passage of gas in the high pressure phase is used, wherein either the first lateral surface portion (16a) has a good thermal conductivity or in the region of the rotation axis (4) a supply channel for fuel is provided, which via a radially extending feed line with the thin channel portion (10a), in the region of the first lateral surface portion ( 16a), and that the rotatable body has a second, closer to the axis arranged lateral surface portion (16b), which has a good thermal conductivity.

20. Thermodynamic turbomachine according to one of claims 16 to 19, characterized in that the channel (2) has a near-axis outlet (8), and that the turbomachine has a turbine which communicates with the outlet (8).

21. Thermodynamic turbomachine according to claim 13 or 14, characterized in that the channel (2) has a parallel and close to the axis of the rotating body extending portion having an inner wall with good thermal conductivity.

22. Thermodynamic turbomachine according to claim 13 or 14, characterized in that the channel (2) has an inlet (6) and an outlet (8) for the gas in the area close to the axis.

3. Thermodynamic turbomachine according to one of claims 13 to 22, characterized in that it comprises a compressor which is adapted to promote the gas via a near-axis inlet (6) in the channel (2).