JPH03111625A - Thermal electric power generating system for space use - Google Patents

Abstract

PURPOSE:To efficiently cool a claw pole generator by supplying a gas which is cooled by adiabatic expansion via a cooling gas turbine and further cooled sufficiently by heat radiation into space via a second radiator. CONSTITUTION:Cooling gas branched at a branch inlet A from a main cycle gas line is expanded by a cooling gas turbine 8, thus obtaining an auxiliary drive force. The cooling gas is decreased in temperature by a second heat radiator 7 are supplied to cool a generator 1. The temperature increased gas discharged from the generator 1 is compressed by a cooling gas compressor 9 to be returned to the main cycle gas line at a combined outlet B. A mechanical loss inside the generator 1 can be reduced as well as intrusive heat from a turbine 2 can be prevented so that the cooling gas at a considerably low temperature can be supplied, thereby cooling the generator 1 efficiently. Since the branch inlet A and the combined outlet B on the branched cycle gas line are in the same thermal condition region, the efficiency of the main cycle gas line is nearly unchangeable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a space thermal power generation system that supplies power to a spacecraft by concentrating thermal power generation.

(Conventional technology) The power demand at the space base is different from the small output, short-term power generation of the space shuttle, etc., and the power generation is large-output, long-term power generation. Therefore, the power generation/storage system of solar power generation and storage batteries is However, there are many problems in terms of area and weight, so a solar thermal engine power generation system consisting of a solar collector, a heat receiver, a heat engine generator, and a radiator is promising. Furthermore, as a thermal cycle in this solar thermal engine power generation system, the Brayton cycle (thermodynamic cycle consisting of two constant entropy processes and two constant pressure processes) is the most promising in the space environment where 1 gravity is extremely small.

Figures 3 and 5 show system diagrams of two types of conventional Brayton cycle space thermal power generation systems, and Figures 4 and 6 are T-8 diagrams of the cycles, with O marks. The symbols with asterisks indicate the corresponding piping positions in both cases.

The system diagram in Figure 3 basically shows the configuration of a normal Brayton cycle regeneration cycle, in which the working medium gas with the lowest temperature in the system after exiting from radiator 0 is used to cool the generator ■. The system is to do so.

In other words, in the Brayton cycle, the working medium gas, which has been heated and pressurized by the compressor (2), is heated by exchanging heat with the exhaust gas of the turbine (2) in the regenerative heat exchanger (0), and then raised to a predetermined temperature in the heat receiver (0). Inflate with ■. The driving force of this turbine (■) rotates the generator (■) and compressor (■). Exhaust gas exiting the turbine (2) passes through the regenerative heat exchanger (0), lowers its temperature in the radiator (2), cools the generator (0), and then is supplied to the compressor (2).

This will be explained using the T-8 diagram shown in FIG.

Internal gas leaving the compressor ■ is used as cycle gas.
The temperature is raised at the same pressure in the regenerative heat exchanger 0, which is the same as the point ``■'' in the T-S diagram, so it rises to the ``■'' position, rises again in the heat receiver (A), and reaches the ``■'' position. This (2) → (3) →
■ is an isobaric change. The cycle gas that has reached the position (2) performs adiabatic expansion work in the turbine (3) and is decompressed and temperature-reduced to the position (2) by turning the generator 0) and compressor 0. The cycle gas at the outlet (■) of the turbine (2) exchanges heat with the cycle gas (2) exiting the compressor (2) in the regenerative heat exchanger 0, and its temperature is reduced to (2) while maintaining the same pressure. Then, the heat radiator ■ radiates the heat outside and reduces the temperature to ■. The cycle gas that exits the radiator (2) is heated to (2) by cooling the generator, and is then supplied to the compressor (3), where the cycle gas is heated to (2) by adiabatic compression of 7.

The system shown in FIG. 5 has a configuration in which the cooling gas from one generator (2) is branched off at the outlet of the compressor (2), and the temperature is reduced to a predetermined temperature by a second radiator (2) placed separately before use. In the working medium gas system, the gas whose temperature has been reduced by the radiator 0 is heated and pressurized by the compressor ■, and although the main system is directly supplied to the regenerative heat exchanger 0, is cooled by the second heat radiator (2), then cools the generator (G), and is supplied to the regenerative heat exchanger (0). expands and drives the generator ■ and compressor ■. The gas exiting the turbine (2) is cooled down by the regenerative heat exchanger (0) and the radiator (2).

The system shown in Figure 5 is explained using the T-3 diagram shown in Figure 6.
Compressor (3) → Regenerative heat exchanger 0 → Heat receiver (a) →
The basic system of turbine (2) → regenerative heat exchanger 0 → radiator (5) → compressor ■ is shown on the T-3 diagram as (1) → (
Flows in the order of 2)→(3)→■→(5)→(6)→■.

The cycle gas branched at the outlet of the compressor ■ is cooled down to ■ by the second radiator ■, heated to ■ by the generator (υ), merges with the gas [phase] at the outlet of the regenerative heat exchanger, and reaches the temperature of ■. becomes.

On the other hand, a claw pole generator is used as the generator in order to increase cycle efficiency and reduce size and weight. FIGS. 7 and 8 are a vertical cross section and a cross section taken along line A--A of the relevant part thereof, showing the principle structure of a conventional claw pole generator.

The rotor (10), which is the rotor shaft of the generator, is supported by bearings (11) and bearing brackets (12) provided at both shaft ends, and the bearing brackets (12) are supported by the stator frame (1
3), and a stator core (15) containing an armature winding (14) is fitted into the center of the stator frame (13) via a core support tube (13a) made of a non-magnetic material. ing.

As shown in the cross section in Fig. 8, the rotor (10) is divided into two parts in the axial direction, and the central cross section of the rotor (10) is divided into N and S poles respectively.
It is magnetized as a pole and made by butt welding with a non-magnetic member (16). The rotor (10) with this two-pole permanent magnet becomes a mechanically rigid rotor and is suitable for an ultra-high speed rotating body.

When this Cropol generator is used in a Brayton cycle power generation system, a turbine (3) and a compressor (3) are attached to the end of the rotor shaft, as shown in Figure 9.
Particularly in the case of space thermal power generation, in order to reduce the size and weight of the generator, which is heavier than the turbine blades and compressor blades, it is necessary to rotate at extremely high speeds. Therefore, mechanical heat loss such as windage loss increases. In addition, in the Brayton cycle, the temperature at the entrance and exit of the turbine is much higher than the allowable temperature of the various windings that make up the generator, so the stator frame (
13) Due to heat conduction, the allowable temperature of various windings is exceeded. Furthermore, in space, the only way to dissipate heat to the outside is through radiation, which has poor cooling efficiency, and the only means of cooling is to use cycle gas. However, in order to improve the efficiency of the heat exchanger, a mixture of 11g gas and Xe with a large molecular weight at an appropriate ratio is used as the cycle gas, so the specific gravity is high and mechanical heat loss is large. The temperature rise in the wire becomes a problem.

(Problems to be Solved by the Invention) Problems in such a conventional Brayton cycle type space thermal power generation system are as follows.

(1) To rotate the generator rotor at ultra high speed.

Since the mechanical loss in the rotor and bearing parts is large,
Cooling cannot be achieved by natural convection and heat conduction.

■ Heat conduction from the high-temperature turbine side causes the temperature in the windings and bearings to rise, exceeding the allowable temperature.

■ If cycle gas is used to cool the generator, the temperature of the cycle gas will rise significantly.

The temperature of the components inside the generator rises and exceeds the allowable temperature.

(b) As shown in Figures 3 and 4, the temperature of the cycle gas after leaving the radiator is the lowest and is most suitable for cooling, but the pressure loss is large, so the cycle gas is not sufficiently supplied into the generator. Supplying is the inner wall.

■ The temperature of the cycle gas at the compressor outlet ■, which has the second lowest temperature in the cycle of FIGS. 5 and 6, is too high.

■ In the case of Figures 5 and 6, even if the cycle gas branched from the compressor outlet is cooled and used to cool the generator, the pressure loss is large and even if the temperature rises, the cycle gas is Since the cycle gas cannot be supplied to the generator, the only means is to directly combine it with the cycle gas at the turbine outlet, and this cycle gas cannot be used for the driving force of the generator, resulting in a decrease in efficiency.

The present invention is a claw point system that rotates a rotor at ultra-high speed in a space thermal power generation system that is required to be compact and lightweight.
- The purpose is to efficiently cool the generator.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a driving turbine in which a cooling gas turbine is provided at one shaft end of a rotor of a generator with a cooling gas turbine placed inside.

a compressor provided at the other shaft end of the rotor in parallel with a cooling gas compressor, a heat receiver that receives sunlight to make the internal gas high temperature and high pressure, and a radiator that cools the internal gas without receiving sunlight; It is equipped with a regenerative heat exchanger that exchanges heat with the internal gas and a second radiator that cools the internal gas that enters the generator, and is used as cycle gas at the inlet of the compressor (1) →
Compressor outlet (2) → Heat receiver side of regenerative heat exchanger (
3) → Heat receiver → Drive turbine (5) → Heat radiator side of regenerative heat exchanger (6) → From radiator to compressor inlet (
1) The piping forming the Brayton cycle connected to 1) and the radiator side piping of the regenerative heat exchanger are branched at the branch inlet to connect the cooling gas turbine (6) → second radiator (7) → generator (3) → Cooling gas compressor ■ → Confluence outlet (10) to regenerative heat exchanger → Cooling gas turbine (6) Piping that forms a branched cycle is provided.

(Function) In this way, the cycle gas that has been adiabatically expanded and cooled by the cooling gas turbine is further radiated into space by the second radiator, and the sufficiently cooled gas is supplied to the generator, and the turbine Since the cooling gas turbine is interposed between the generator and the generator W1, the intrusion heat due to conduction from the high-temperature turbine is blocked, so it is possible to obtain a space thermal power generation system that can efficiently cool the generator.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

The system diagram in Figure 1 basically has a regenerative Brayton cycle configuration, and the flow of main cycle gas is from compressor (3) to regenerative heat exchanger 0 to heat receiver) to turbine (
2) It flows in the order of → regenerative heat exchanger 0 → radiator 0 → compressor ■, and the driving force of turbine ■ rotates the generator (1) and compressor ■ to generate electricity.

When cooling a generator using this cycle gas 5 In this embodiment, in order not to obstruct the flow of cycle gas, the gas is branched after exiting the regenerative heat exchanger 0, and the cooling gas turbine ( c) to obtain auxiliary driving force, and after cooling it in the second radiator (iii), it is supplied to the generator (1).
) to cool down. The heated cycle gas after exiting the generator (1) is compressed by a cooling gas compressor (O) and returned to the outlet of the turbine (2). The symbols filled in with circles in Figures 1 and 2 indicate the corresponding positions in both, and the cycle gas is compressor inlet (1) → compressor outlet (2) → regenerated heat. Heat receiver side of the exchanger (3) → Heat receiver → Drive turbine (
5) → The radiator side of the regenerative heat exchanger (6) → The piping that forms the Brayton cycle connecting the radiator to the compressor inlet (1), and the radiator side piping of the regenerative heat exchanger to the branch entrance branch for cooling gas turbine (6) → second radiator (7) → generator (3) → cooling gas compressor →
Piping is provided to form a branched cycle from the confluence outlet (10) to the regenerative heat exchanger to the cooling gas turbine (6).

Next, the operation of this embodiment will be explained. With this system configuration, the cycle gas supplied to the inside of one generator (υ) is at low pressure, so mechanical heat loss can be kept small, and the gas flow is also low, so
) has the effect of lowering the humidity of the components inside. In addition, the intrusion heat due to conduction from the high-temperature turbine ■ is absorbed by the generator α) because the cooling gas turbine (c) is installed between them.
It also has the effect of reducing heat intrusion into the interior.

Due to these two functions, the generator (1) can be driven within the permissible temperature range, and the cycle gas branched for cooling the generator (O) is sent to the cooling gas turbine (to) and the cooling gas compressor. 0, it is possible to maintain a predetermined pressure value, and the branch inlet of the branch cycle gas (A
) and the confluence outlet (B) are in the same thermal state range of the main cycle gas, so there is an effect that the efficiency of the main cycle gas is almost unchanged.

In addition, the cooling gas turbine (c) and compressor ■ are
Since it is much lighter and more compact than a generator, it has no effect in terms of weight and size.

〔Effect of the invention〕

As explained above, according to the present invention, the cooling gas branched from the main cycle gas is passed through the cooling gas turbine → second radiator → generator → cooling gas compressor, and returned to the original main cycle gas line. This reduces mechanical loss in the generator, which has a rotor that rotates at ultra-high speed, and prevents heat from entering from the high-temperature turbine.It also supplies cooling gas at a fairly low temperature, making it possible to Allows rotation at high speed. In addition, since the thermal state of the gas and the gas flow rate do not change in each component of the main cycle gas, there is no effect on cycle efficiency, and there is no effect on weight or size. It is possible to provide a space thermal power generation system.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the space thermal power generation system of the present invention, Fig. 2 is a T-3 diagram showing the relationship between temperature and entropy in Fig. 1, and Fig. 3 is a system diagram showing an example of the space thermal power generation system of the present invention. Genealogical diagram showing examples,
Figure 4 is the T-8 diagram of Figure 3, Figure 5 is a system diagram showing the second conventional example, Figure 6 is the T-3 diagram of Figure 5, and Figure 7 is the same as Figure 1. An explanatory vertical cross-sectional view for explaining the principle of the generator used, Fig. 8 is a cross-sectional view taken along the line A-A of the rotor in Fig. 7, and Fig. 9 is used for the conventional example shown in Fig. 3. FIG. 1... Generator, 2... Turbine, 3
...Compressor, 4...Heat receiver, 5...
radiator, 6... regenerative heat exchanger, 7...
Second radiator. 8...Turbine for cooling gas. 9... Cooling gas compressor, A... Branch inlet, B... Merging outlet, ■
Or O...Cycle gas piping.

Claims (1)

[Claims] A driving turbine is provided on one shaft end of the generator rotor with a cooling gas turbine placed inside, a compressor is provided on the other shaft end of the rotor in parallel with the cooling gas compressor, and a compressor that receives sunlight A heat receiver that makes the internal gas high temperature and high pressure, a radiator that cools the internal gas without receiving sunlight, a regenerative heat exchanger that exchanges heat with the internal gas, and a second heat radiator that cools the internal gas that enters the generator. The cycle gas is supplied to the compressor inlet (1) → the compressor outlet (2) → the heat receiver side of the regenerative heat exchanger (3) → the heat receiver (4).
) → Drive turbine (5) → Heat radiator side of the regenerative heat exchanger (6) → Piping forming the Brayton cycle connecting the radiator to the compressor inlet (1) and the radiator of the regenerative heat exchanger The side pipe is branched at the branch inlet to connect the cooling gas turbine (6) → second radiator (7) → generator (8) → cooling gas compressor (9) → confluence outlet to the regenerative heat exchanger ( 10) → A space thermal power generation system characterized by being provided with piping forming a branched cycle serving as a cooling gas turbine (6).