CN114038599B

CN114038599B - Direct circulation control drum type nuclear power engine

Info

Publication number: CN114038599B
Application number: CN202111241387.6A
Authority: CN
Inventors: 赵富龙; 何宇豪; 卢瑞博; 谭思超; 刘凯; 胡朝营; 宁可为; 田瑞峰
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2021-10-25
Filing date: 2021-10-25
Publication date: 2023-09-19
Anticipated expiration: 2041-10-25
Also published as: CN114038599A

Abstract

The invention provides a direct circulation control drum type nuclear power engine, which comprises a reactor core reflecting layer, a control drum system, a radiation shielding body, a pressure vessel, a reactor core, a blade adjustable compressor, a blade adjustable turbine, a stationary blade grid, a diffuser and a tail nozzle, wherein the reactor core, the blade adjustable compressor, the blade adjustable turbine, the stationary blade grid, the diffuser and the tail nozzle are arranged in the pressure vessel; the control drum system comprises 8 groups of control drum elements, each group of control drum elements consists of a neutron absorber, a drum driving mechanism and a drum channel, the drum channel provides an accommodating space and a rotating space for the neutron absorber, and the whole control drum system is uniformly arranged in a reactor core reflecting layer at the same interval; the invention provides a long-endurance, high-thrust, safe and reliable direct-circulation-control drum-type nuclear power engine, which is provided with an adjustable compressor and turbine blades, can adapt to different space heights, and can solve the problems that the traditional aircraft engine cannot utilize adjacent space and has limited endurance mileage.

Description

Direct circulation control drum type nuclear power engine

Technical Field

The invention relates to the field of nuclear reactor engineering technology and power plant design, in particular to a nuclear power engine device.

Background

A nuclear fission reaction is a process in which one heavy nucleus absorbs one neutron and then splits into two light nuclei. Each nuclear fission releases a large amount of energy to be utilized, and on the other hand, new neutrons are generated, and the new neutrons continue to cause more heavy nuclear fission, so that a chain fission reaction is continuously formed, and a large amount of energy is continuously released. In the process of nuclear fission, the number of neutrons bombarded on the atomic nucleus of the previous generation is basically equal to that of neutrons bombarded on the atomic nucleus of the next generation, so that a critical state can be achieved, and nuclear energy released by the nuclear fission is basically stable and can be fully utilized. The equipment controlling such chain reactions is commonly referred to as a "nuclear reactor", which is the primary device that uses nuclear energy.

Compared with other energy sources, the nuclear energy has the advantages of high energy density, strong endurance and high power level, wherein the energy released by the total fission of 1 kg uranium-235 is approximately equal to the energy released by the combustion of 2700 tons of standard coal, and the nuclear energy can execute the flight tasks of ocean areas, remote areas or long mission cycles, wherein the conventional power cannot be used for frequently supplementing fuel; the nuclear energy can provide higher power, and as the required thermal power increases, the conventional chemical energy advantage gradually decreases, and the nuclear energy advantage becomes more pronounced.

Near space refers to the area between the atmospheric area from an altitude of about 20km to 100km above the earth's surface. Near space is almost a blind area that is not available to humans because the space altitude is too high for most aircraft and too low for satellites. In recent years, the significance of the near space in weather forecast, electromagnetic communication, high-resolution wide imaging and the like is gradually highlighted. The nuclear aircraft engine has the advantages of high power density, long service life, large thrust and wide coverage range, and can be designed as a near space aircraft engine. The development of the engine of the nuclear power aircraft which is suitable for the high power, high thrust, high specific impulse, long endurance, long range, high speed, safety and reliability of the space environment is not slow in view of the development and utilization of space resources or the strategic requirements of national safety. The nuclear power ramjet engine has a plurality of advantages which are incomparable with other energy sources, has the outstanding advantages of high specific impulse, high energy density, long endurance, large thrust, wide coverage range and the like, and has great application potential in various civil aerospace tasks due to the excellent performance. However, related researches and designs on the nuclear power ramjet engine are few at present, and the critical space operation environment is severe, so that great technical difficulty is brought to the design of an engine scheme with good environmental adaptability and high safety and reliability.

Disclosure of Invention

The invention aims to provide a long-endurance, high-thrust, safe and reliable direct-circulation-control drum-type nuclear power engine, which is provided with an adjustable compressor and turbine blades, can adapt to different space heights, can overcome the problem that a traditional aircraft engine cannot utilize adjacent space, and simultaneously solves the problem that the conventional aircraft has limited endurance mileage by taking a nuclear fission reactor as an energy source.

The purpose of the invention is realized in the following way:

a direct cycle control drum type nuclear power engine, which comprises a reactor system, a compressor system, a turbine system, a rotating shaft 11 and a pressure vessel 5 which are connected; the reactor system comprises a reactor core fuel 10, an upper grid plate 14, a lower grid plate 15, a reflecting layer 7, a control drum channel 18, a control drum absorber 8, springs 17 and a shield 9; the reactor core fuel 10 is fixed by an upper grid plate 14 and a lower grid plate 15 and is connected with a rotating shaft, the reflecting layer 7 surrounds the outside of the pressure vessel 5 and is connected with the pressure vessel 5, eight control drum channels 18 are uniformly distributed on the periphery of the reflecting layer 7, a control drum absorber 8 is arranged in each control drum channel 18, the control drum absorber 8 is tightly attached to the inner wall of one side of the control drum channel 18 and can rotate in the control drum channel 18, when the control drum absorber 8 is turned to be close to one side of the pressure vessel 5, the control drum absorber 8 has the maximum absorption capacity for neutrons in the reactor, at the moment, the neutrons cannot be absorbed and can not maintain a chain fission reactor, the reactor is in a subcritical or a reactor stopping state, when the control drum absorber 8 is turned to be far away from one side of the pressure vessel 5, at the moment, the absorption effect of the control drum absorber 8 on neutrons in the reactor is the weakest, the reactor is the largest, the position of the control drum absorber 8 can continuously change along with the consumption of the fuel 10 and the output power of an engine in the whole service life, and the reactor is gradually turned to the reactor core 10 along with the continuous running of the control drum system, and the reactor core 10 is kept in the critical state and the reactor core is kept far away from the reactor 5. When the output power of the reactor needs to be reduced, the drum absorber 8 is controlled to rotate to a direction away from the pressure vessel 5, so that the effective increment factor of the reactor is reduced to be less than 1, the power starts to be gradually reduced, and when the expected power is reached, the drum absorber 8 is controlled to rotate to a direction close to the pressure vessel 5, so that the effective increment factor of the reactor is kept between 1.00 and 1.02, and the chain reaction and the required power are maintained. In order to ensure a uniform power distribution of the reactor, the rotation of all control drum absorbers 8 needs to be kept uniform and not individually rotatable during normal operation.

A spring 17 for automatic emergency shutdown is arranged in the control drum channel, and when the reactor is in an accident working condition or cannot be controlled normally, the control drum absorber 8 is rotated and faces the reactor core by means of elastic potential energy of the spring 17;

the compressor system comprises a stator blade grid fixer 1, a stator blade grid 2, a diffuser 12, a primary blade 3, a secondary blade 4 and a secondary blade 6, when the flying speed is low, air enters the compressor after passing through the stator blade grid 2 in the advancing direction, is gradually decelerated and pressurized by the compressor blade to form high-pressure air flow, the flying height is continuously lifted along with the gradual increase of the flying speed, the blocking effect of the compressor blade on the air is gradually reduced by gradually adjusting the included angle between the blade angle and the entering air, when the flying speed exceeds Mach number 1, the blade angle is adjusted to be completely perpendicular to the air inlet direction, and the air is contracted towards the rotating shaft 11, so that the blade does not have the blocking effect on the air, and at the moment, the compressor can be equivalent to the diffuser 12 without the blade, the air is directly decelerated and pressurized in the diffuser 12 to form the high-pressure air flow;

the turbine system comprises a rotating shaft 11, a tail nozzle chamber 13 and turbine blades 16, when the flying speed is low, high-temperature high-pressure air flow which is pressurized by the compressor system and heated by the reactor core enters the turbine system, and at the moment, the high-temperature high-pressure air flow is depressurized and accelerated, is discharged at a high speed at the turbine, and thrust is generated by utilizing the action force and reaction force principles; as the flight speed increases, the blades 16 are gradually rotated to adjust the angle so that the obstructing effect of the turbine blades 16 on the air decreases gradually. When the flying speed reaches Mach 1, the angle of the blades 16 is adjusted to be completely perpendicular to the air inlet direction, and the blades shrink towards the direction of the rotating shaft 11, so that the blades do not have an obstruction effect on air, at the moment, the turbine can be equivalently used as the tail nozzle chamber 13, high-temperature and high-pressure air is decompressed, accelerated and discharged in the tail nozzle chamber 13, and thrust is generated; the adjustable turbine blade 16 participates in the adjustment of the output power and the thrust of the engine at the same time, the angle of the turbine blade 16 is adjusted and increased according to the actually required output power, when the flying height is higher but the flying speed needs to be reduced, the angle of the turbine blade 16 is rotated to increase the blocking effect of the turbine blade on the air, the turbine generates the thrust after the flying speed is reduced, and then the angle of the turbine blade 16 is rotated to adjust the thrust generated by the engine.

The maximum effective increment factor of the reactor is 1.06, so that the control drum system can accurately adjust the reactivity, and the safety of the reactor is improved;

the reactor fuel 10 is a ceramic type UO2 fuel with high enrichment.

The reactor can continuously provide energy supply for the engine for not less than 5 days, so that the ultra-long-distance and long-time operation is realized.

Compared with the prior art, the invention has the beneficial effects that:

the invention uses nuclear reactor to replace the combustion chamber of the traditional engine, realizes the conversion from reactor fission energy to heat energy through the compressor and the turbine with adjustable blades, and then generates thrust through the turbine system. Air enters the engine from the advancing direction of the aircraft, passes through the compressor, the reactor core and the turbine sequentially in one direct cycle, and finally is discharged out of the engine at an extremely high speed so as to generate thrust, and the engine has a simple cycle mode and a simple and reliable system.

The long-endurance characteristic of the nuclear reactor provides continuous energy supply for the engine not lower than 5 days, ensures that an aircraft carrying the engine has enough time to reach any position of the earth, and realizes the effect of infinite voyage.

The reflecting layer surrounds the periphery of the reactor core, and reflects neutrons emitted from the interior of the reactor core back to the reactor core again, so that the neutron economy of the reactor core is improved, and the reactor core volume is reduced. The shielding body is arranged on the periphery of the reflecting layer to serve as a boundary of the reactor system, and absorbs and shields nuclear radiation from the direction of the reactor core so as to ensure the radiation safety of the aircraft. The reflecting layer and the shielding body are concentric circles surrounding the reactor core and the periphery of the pressure vessel, so that the overall quality of the engine is reduced, and the arrangement is more compact and reasonable. The reactor is controlled by adopting a control drum, the control drum system is arranged inside the reflecting layer, and the automatic emergency shutdown of the reactor core can be realized when the reactor is in accident by adopting the design of spring emergency shutdown. The compressor is provided with the multistage blades, air is compressed step by step, meanwhile, the angle of the blades is adjustable, conversion between the multistage compressor and the diffuser can be realized according to the flight speed of an aircraft, the turbine blades can also be adjusted according to the flight speed, conversion between the turbine and the tail nozzle is realized, and the design ensures that the engine integrates the advantages of the turbine engine at a low speed and the advantages of the ramjet engine at a high speed, so that the engine has a wider flight envelope, and the range and the variety of executing tasks are promoted.

Drawings

FIG. 1 is a structural elevation view of a nuclear powered engine system of the present invention;

FIG. 2 is a top view of the nuclear power engine system of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and the detailed description.

The icon illustrates: 1. a static cascade fixer; 2. static leaf grating; 3. a primary blade; 4. a secondary blade; 5. a pressure vessel; 6. a secondary blade; 7. a reflective layer; 8. a control drum absorber; 9. a shield; 10. reactor fuel; 11. a rotating shaft; 12. a diffuser; 13. a tail pipe chamber; 14. an upper grid plate; 15. a lower grid plate; 16. a blade; 17. a spring; 18. the drum channels are controlled.

The invention relates to a direct circulation control drum type nuclear power engine, which comprises a reactor core reflecting layer, a control drum system, a radiation shielding body, a pressure vessel, a reactor core arranged in the pressure vessel, a blade adjustable compressor, a blade adjustable turbine, a stationary blade grid, a diffuser and a tail nozzle, wherein the reactor core is arranged in the pressure vessel; the control drum system comprises 8 groups of control drum elements, each group of control drum elements consists of a control drum absorber 8, a drum driving mechanism and a drum channel 18, the drum channel 18 provides a containing space and a rotating space for the control drum absorber 8, the whole control drum system is uniformly arranged in the reactor core reflecting layer 7, and the radiation shielding body 9 is arranged at the periphery of the reactor core reflecting layer 7 and is used as one of the outer boundaries of the device; the pressure vessel 5 is used for accommodating a reactor core, a compressor, a turbine, a stator blade grid and the like and bearing pressure at the same time, and the pressure vessel 5 is arranged in the reactor core reflecting layer 7 so as to make the system more compact and lighter; the blade-adjustable compressor comprises a plurality of stages of blades, and air enters the compressor to be compressed step by step through the blades when the flying speed is low, so that the air enters the reactor core at a high pressure; when the flying speed of the aircraft is high, the angle of the blades changes and contracts towards the direction of the rotating shaft, and the blocking effect of the blades is reduced, so that the compressor compresses high-speed airflow in the form of a diffuser 12 and sends the compressed high-speed airflow into a reactor core; the high-pressure air flows are heated to a higher temperature through the reactor core and then enter the turbine to do work to generate thrust, when the flying height is higher, the angle of the turbine blades changes and contracts towards the direction of the rotating shaft, and the turbine enables the high-temperature high-speed air to be decompressed and accelerated at the nozzle in the form of the tail nozzle 13 so as to generate extremely large thrust.

The invention may further include:

1. the maximum effective multiplication factor of the reactor at the beginning of the life period is not more than 1.06, the adjustment accuracy of the control drum on the reactivity can be ensured, and the high safety of the reactor is ensured.

2. High enrichment of reactor fuel selectionCeramic UO of (2) ₂ And (3) fuel.

3. The compressor and the turbine with the adjustable blade angles can be switched between the ramjet engine and the turbine engine according to the flying speed of the aircraft, and continuous and stable adjustment of output power and thrust can be realized.

4. The reactor core coolant is air, and adopts the design of direct circulation of air.

5. The reactor control drum is provided with emergency shutdown equipment, and the emergency shutdown equipment can automatically shut down the reactor under the accident working condition of the reactor.

6. The compressor and turbine are arranged horizontally and coaxially.

7. The effective multiplication factor of the reactor core is lower than 1 under the accident working condition, so that the reactor can be stopped under any working condition.

8. The reactor may continuously power the engine for a period of not less than 5 days.

The working principle of the system is as follows: a nuclear power engine is an engine that uses a small reactor instead of a combustion chamber as a heat source on the basis of a conventional power engine. Air enters the compressor system of the engine from the advancing direction of the aircraft, when the flying speed is low, the air enters the reactor after being gradually pressurized by the compressor blades, and after the high-pressure air is heated by the reactor, the high-pressure high-temperature air flow drives the turbine to generate thrust. Along with the gradual increase of the flying speed, the continuous lifting of the flying height gradually reduces the blocking effect of the blades on the gas by gradually adjusting the angle between the blades and the entering air, when the flying speed exceeds Mach 1, the angle of the blades is adjusted to be completely perpendicular to the air inlet direction and is contracted towards the direction of the rotating shaft 11, the blades do not block the air, at the moment, the compressor can be equivalent to a diffuser 12 without the blades, the air is directly subjected to deceleration and pressurization in the diffuser 12 to form high-pressure air flow, the compressor can be equivalent to the diffuser 12 without the blades, the air is directly subjected to deceleration and pressurization in the diffuser 12, and finally the air is expanded and discharged through the tail nozzle to generate thrust.

The invention replaces the combustion chamber of the traditional aircraft engine with the nuclear reactor core, realizes almost infinite voyage, adopts the design of direct air circulation, simplifies the system layout and reduces the quality of the system. The eight groups of control drums are used as a control system for the reactor core, so that the layout of the reactor core is more compact, when the control drum absorber 8 turns to the side close to the pressure vessel 5, the control drum absorber 8 has the maximum absorption capacity for neutrons in the reactor, at the moment, the reactor is in a subcritical or shutdown state because neutrons are absorbed, when the control drum absorber 8 turns to the side far away from the pressure vessel 5, the absorption effect of the control drum absorber 8 for neutrons in the reactor is the weakest, the reactivity of the reactor is the maximum, the position of the control drum absorber 8 continuously changes along with the consumption of the reactor core fuel 10 and the output power of an engine during the whole service life, the nuclear fuel 10 gradually is consumed along with the continuous operation of the reactor system, so that the effective increment factor of the reactor is reduced, and at the moment, in order to keep the reactor in a critical state, the control drum absorber 8 rotates in the direction far away from the pressure vessel 5. When the output power of the reactor needs to be reduced, the drum absorber 8 is controlled to rotate to a direction away from the pressure vessel 5, so that the effective increment factor of the reactor is reduced to be less than 1, the power starts to be gradually reduced, and when the expected power is reached, the drum absorber 8 is controlled to rotate to a direction close to the pressure vessel 5, so that the effective increment factor of the reactor is kept between 1.00 and 1.02, and the chain reaction and the required power are maintained. In order to ensure a uniform power distribution of the reactor, the rotation of all control drum absorbers 8 needs to be kept uniform and not individually rotatable during normal operation. The springs 17 can rapidly rotate the control drum absorber toward the core under accident conditions to achieve emergency shutdown of the reactor, making the entire reactor system safer. The design of the circumferential shield ensures radiation safety of instruments and equipment and the like in the aircraft, while reducing the volume of the shield as much as possible to reduce the mass. The angle of the turbine blade 16 can be adjusted and increased according to the actual required output power, when the flying height is higher but the flying speed needs to be reduced, the angle of the turbine blade 16 is rotated to increase the blocking effect of the turbine blade on air, the turbine generates thrust after the flying speed is reduced, and then the angle of the turbine blade 16 can be rotated to adjust the thrust generated by the engine. When the flying speed of the aircraft is higher, the aircraft runs in a stamping mode, the advantages of simple structure and large thrust-weight ratio of the stamping engine are fully exerted, the aircraft can fly at an extremely high speed for a long time in a cruising mode, meanwhile, the aircraft has the capability of flying in a near space, and when the flying speed of the aircraft is lower, the aircraft can run in a turbine engine mode and can be started under a static condition without depending on other aircrafts.

Claims

1. A direct cycle control drum type nuclear power engine comprises a reactor system, a compressor system, a turbine system, a rotating shaft (11) and a pressure vessel (5) which are connected; the reactor system comprises a reactor core fuel (10), an upper grid plate (14), a lower grid plate (15), a reflecting layer (7), a control drum channel (18), a control drum absorber (8), springs (17) and a shielding body (9), and is characterized in that: the reactor core fuel (10) is fixed by an upper grid plate (14) and a lower grid plate (15) and is connected with a rotating shaft (11), a reflecting layer (7) surrounds the outside of the pressure vessel (5) and is connected with the pressure vessel (5), eight control drum channels (18) are uniformly distributed in the circumferential direction of the reflecting layer (7), each control drum channel is internally provided with a control drum absorber (8), the control drum absorber (8) can freely rotate in the control drum channel (18), the reactor is in a reactor stopping state when the control drum absorber (8) is turned to a side close to the pressure vessel (5), the reactor reactivity of the reactor is maximized when the control drum absorber (8) is turned to a side far away from the pressure vessel (5), the position of the control drum absorber (8) can be continuously changed along with the consumption of the reactor core fuel (10) and the output power of an engine in the whole service life, a spring (17) for automatically stopping emergency reactor is arranged in the control drum channels (18), or the reactor can not be controlled to rotate normally by means of the spring (17).

2. The direct cycle control drum type nuclear power engine according to claim 1, wherein the compressor system comprises a static blade grid fixer (1), a static blade grid (2), a diffuser (12), a primary blade (3), a secondary blade (4) and a secondary blade (6), when the flying speed is low, air enters the compressor after the air inlet angle is adjusted by the static blade grid from the advancing direction, and high-pressure air flow is formed after the air is gradually decelerated and pressurized by the compressor blade, the air is not beneficial to the pressurization of the air after the flying height is lifted along with the increasing of the flying speed, the compressor blade gradually rotates to be perpendicular to the air inlet direction and contracts towards the rotating shaft direction, so that the blocking effect of the blade on the air is reduced, and at the moment, the compressor can be equivalently used as a diffuser, and the air is decelerated and pressurized in the diffuser, so that the high-pressure air flow is formed.

3. The direct cycle control drum nuclear power engine of claim 1 wherein the turbine system includes a shaft (11), a nozzle chamber (13) and turbine blades (16); when the flying speed is lower, the high-temperature high-pressure air flow which is pressurized by the compressor system and heated by the reactor core enters the turbine system, and at the moment, the high-temperature high-pressure air flow is decompressed and accelerated, is discharged at a high speed at the turbine, and thrust is generated by utilizing the acting force and reaction force principles; when the flying speed is higher, the angle of the adjusting blade (16) is perpendicular to the air inlet direction and contracts towards the rotating shaft (11), so that the effect of the turbine blade (16) is reduced, the turbine is equivalent to the tail nozzle chamber (13), high-temperature and high-pressure air is decompressed and accelerated in the tail nozzle chamber (13) and discharged, and meanwhile, thrust is generated; the adjustable turbine blades (16) are simultaneously involved in the regulation of the engine output power and the thrust magnitude, and when the flying height is higher than the air inflow, the angle is rotated according to the required thrust magnitude to adjust the thrust generated by the engine.

4. The direct cycle control drum nuclear power engine of claim 1, wherein the reactor design maximum effective increment factor in the reactor system is 1.06 to ensure accurate adjustment of reactivity by the control drum system to improve reactor safety.

5. The direct cycle control drum nuclear power engine of claim 1 wherein the reactor fuel in the reactor system is a high enrichment ceramic UO2 fuel.

6. A direct cycle control drum type nuclear power engine as claimed in any one of claims 1 to 3, wherein the reactor is adapted to provide the engine with energy for not less than 5 days for ultra long distance, long term operation.