CN116104665A - Combined detonation engine, aircraft and combined detonation method - Google Patents

Abstract

The invention provides a combined detonation engine, an aircraft and a combined detonation method.A variable boss structure is arranged on an inner column, the variable boss structure is composed of at least two variable hierarchical structures, and the lengths of the variable hierarchical structures are sequentially increased along the incoming flow direction; the inclination angles of the adjustable hierarchical structures are consistent under the rotary detonation combustion mode, mach numbers are increased to the second Mach number, the inclination angles of the adjustable hierarchical structures are adjusted to enable the inclination angles of the adjustable hierarchical structures to be sequentially reduced along the incoming flow direction, the adjustable boss structures induce detonation and oblique detonation, the engine is converted from the rotary detonation combustion mode to the oblique detonation combustion mode, and the inclination angles of the adjustable hierarchical structures are sequentially reduced along the incoming flow direction under the oblique detonation combustion mode. The invention utilizes the unique advantages of detonation combustion, combines two modes of rotary detonation and oblique detonation, can greatly widen the speed domain and the airspace of the engine, shortens the size of the engine, greatly improves the effective load of the engine, and realizes the coverage (Ma2.5-15+) ultra-wide-domain flight.

Description

Combined detonation engine, aircraft and combined detonation method

Technical Field

The invention relates to a combined detonation engine, an aircraft and a combined detonation method, and belongs to the technical field of detonation engines.

Background

With the further exploration of the sky by human beings, the aircraft can reach faster speed, realize more functions and be applied to more different fields, which is a necessary trend of future development. However, the development of aircraft in the "large airspace, wide speed domain" direction is constrained by the power system. Although the traditional rocket engine can realize full-speed field flight, the traditional rocket engine needs to carry an oxidant, so that the effective load is greatly reduced; for the traditional turbine engine and the traditional ramjet engine, the combustion chamber is long, the engine is large in size and structural mass, the friction resistance loss of the inner runner and the difficulty of large-area heat protection are greatly increased, and the possibility that the aircraft flies to a higher altitude and at a higher speed is greatly weakened.

There are two forms of combustion waves in nature, namely slow combustion and knocking. Slow combustion is more common, and flame propagation is dependent on mass and heat diffusion, with propagation speeds typically ranging from a few meters to tens of meters per second. Most aerospace power units (turbine engines and ramjet engines) currently adopt isobaric mode tissue combustion based on slow combustion. Knocking is a combustion mode of strong coupling of shock waves and chemical reactions and supersonic propagation in the order of kilometers per second, can finish release of fuel chemical energy under a shorter space-time scale, and has the characteristics of supersonic propagation, self-pressurization and rapid heat release. Compared with isobaric combustion, the adoption of detonation combustion can improve the cycle thermal efficiency of a power system by more than 30%, reduce the fuel consumption by more than 30%, greatly improve the fuel economy of an engine and is more suitable for being applied to an air suction type power efficient combustion organization. At present, a power device based on detonation combustion mainly comprises a pulse detonation engine, a rotary detonation engine, an inclined detonation engine and the like, wherein the rotary detonation engine has Ma2.5-Ma6.5+ wide-range working capacity, the specific impact performance can be improved by 30% -50% compared with that of a traditional ramjet engine, continuous air inlet is realized, and the structure is compact. The inclined detonation engine has Ma6.5-Ma15+ wide-range working capacity, the static temperature of the combustion chamber is low, a larger temperature difference space is reserved for releasing chemical energy of fuel, the range of operable oil-gas ratio of the engine is wide, the thrust adjusting range is large, the size of the combustion chamber of the inclined detonation engine is small, and the friction loss and the heat protection difficulty can be effectively reduced. In addition, because the oblique detonation combustion speed is high, the combustion can be resident in hypersonic airflow, and a feasible way is provided for realizing the suction type power working process and improving the performance under the higher Mach number. In addition to the fact that the current oblique detonation engine combustion chamber configuration mainly relies on binary physical oblique wedge induced oblique detonation waves, cone induced conical oblique detonation waves are also studied in a related manner, but a large gap is reserved from engineering practice.

For the future aerospace power, the combined engine can greatly widen the working range of the traditional single type engine, and is a development trend of a power system. The current space power combination scheme is approximately provided with two parallel-connection type and serial-connection type, the two flow channels of the parallel-connection type combined engine work independently and are not mutually influenced, but the problems of large structural weight, small thrust-weight ratio of the engine and the like exist, and extra burden is brought to structural design. For a serial combined engine, the mutual conversion of multiple modes can be realized in one flow passage, but the mutual influence is easy to occur before and after different modes in the same flow passage, so the design difficulty is extremely high. In a comprehensive view, the current combined power scheme is complex in structure and difficult to realize ultra-wide-range flight.

Knock engines based on knock combustion are trend of future aerospace power development due to high performance and small size, but no combined power scheme for ultra-wide-range flight based on knock combustion completely exists at present. Firstly, the two combustion chamber flow channel configurations have huge differences: the principle of the rotary detonation engine is that after the explosive mixture formed by fuel and oxidant is detonated, a detonation wave which is rotationally propagated along the circumferential direction is formed at the head part of the combustion chamber, so that the combustion chamber of the rotary detonation engine is required to be an axisymmetric annular flow passage. The principle of the oblique detonation engine is mainly that supersonic combustible mixed gas forms oblique shock waves on the surface of a detonation device and induces combustion, and then the combustion waves are quickly coupled with the oblique shock waves to form oblique detonation waves and stay in high-speed airflow. At present, most combustion chambers of the oblique detonation engines adopt binary wedge induction to generate oblique detonation waves, and whether oblique detonation combustion can be organized in an annular cavity or not and the oblique detonation waves are resident are not studied at present. The complex differences in runner structure have led to very slow progress in current combinatorial power schemes based entirely on efficient detonation combustion. In addition, detonation combustion is supersonic combustion, the heat release rate is extremely fast, the applicable incoming flow working conditions of different detonation combustion modes are quite different, and under the 'connection working conditions' (Ma 6-Ma 7), the full coverage and successful conversion of two detonation combustion modes become a great difficulty. For rotary detonation, the flight conditions of Ma 6-Ma 7 correspond to high total temperature total pressure and high incoming flow speed, and at the moment, the problem that the rotary detonation wave is difficult to self-propagate is encountered that the detonation wave propagation process is unstable, periodic fluctuation of speed occurs, unstable propagation of the detonation wave can be caused due to uneven mixing of fuel and oxidant and supersonic incoming flow, such as change of wave head number and propagation direction in the propagation process, extinction and re-explosion of the detonation wave and the like (Feng Zixuan, wang Aifeng, yao Xuanyu and the like, detonation engine research progress [ J ], gas turbine test and research, 2018, 31 (04): 46-52). And high incoming flow rates can make it difficult for inherently unstable rotary detonation waves to propagate self-sustained in the annular chamber. For oblique detonation combustion, the root of the oblique detonation propulsion is that the high-speed incoming flow suppresses the uploading of detonation waves, and the wedge surfaces in the common oblique detonation engine play roles in continuous ignition and flame stabilization (brilliant, jiang Zonglin, the multi-wave structure of oblique detonation and the research progress of the stability research thereof [ J ], mechanical progress, 2020, 50 (00): 50-92). The flight conditions of Ma 6-Ma 7 are low Mach number conditions for oblique knocking, and correspond to low incoming flow speed and total incoming flow temperature, after air intake compression, static temperature before oblique splitting is low, and ignition initiation of detonation waves is difficult to realize; the low incoming flow speed leads to the fact that the chemical proper ratio is lower than the CJ speed of the mixed gas at the moment, the mixed gas can be separated and forwarded after detonation of the detonation wave, and the mixed gas cannot be resident (Miao Shikun, research on the structure and resident characteristics of the oblique detonation wave in supersonic airflow [ D ]. National defense science and technology university, 2018). Therefore, in the connection working condition, the oblique detonation mode can meet the problems that the oblique detonation wave is difficult to detonate and is difficult to park. Therefore, how to solve the transition and conversion of two combustion modes under the connection working condition is a serious issue of research work.

Disclosure of Invention

The invention aims to overcome one of the defects of the prior art and provides a combined detonation engine, an aircraft and a combined detonation method.

The technical solution of the invention is as follows: a combined detonation engine comprises an inner column and a shell, wherein an annular flow channel is formed between the inner column and the shell, an adjustable boss structure is arranged on the inner column and consists of at least two adjustable hierarchical structures, and the lengths of the adjustable hierarchical structures are sequentially increased along the incoming flow direction;

the inclination angles of the adjustable hierarchical structures are consistent under the rotary detonation combustion mode, mach numbers are increased to the second Mach number, the inclination angles of the adjustable hierarchical structures are adjusted to enable the inclination angles of the adjustable hierarchical structures to be sequentially reduced along the incoming flow direction, the adjustable boss structures induce detonation and oblique detonation, the engine is converted from the rotary detonation combustion mode to the oblique detonation combustion mode, and the inclination angles of the adjustable hierarchical structures are sequentially reduced along the incoming flow direction under the oblique detonation combustion mode.

An aircraft employing any one of the above combinations of detonation engines.

A combined knock method comprising the steps of:

the mode of knocking combustion is rotated,

in the first Mach number, the engine carries out rotary detonation combustion, and the inclination angles of all stages of adjustable hierarchical structures of the adjustable boss structure are consistent and are the inclination angles alpha of the adjustable boss structure under the rotary detonation mode _XZ ；

The transition mode is carried out in such a way that,

the Mach number is increased to a second Mach number, the inclination angles of all levels of adjustable hierarchical structures of the adjustable boss structures are adjusted, and the inclination angles alpha of all levels of adjustable hierarchical structures in the transitional mode along the incoming flow direction are enabled _Gi Sequentially reducing, and converting the engine from a rotary knocking combustion mode to a diagonal knocking combustion mode, wherein i=1, 2 and … n are the stages of the adjustable hierarchical structure;

the combustion mode of the oblique knocking is that,

mach number is increased to a third Mach number, and inclination angle alpha of each stage of adjustable hierarchical structure under oblique detonation combustion mode along incoming flow direction _Xi And sequentially reducing, detonating the blended fuel in the adjustable boss structure to form oblique detonation wave, and performing oblique detonation combustion, wherein i=1, 2 and … n are the stages of the adjustable hierarchical structure.

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

(1) The invention utilizes the unique advantages of detonation combustion, combines two modes of rotary detonation and oblique detonation, can greatly widen the speed domain and the airspace of the engine, shortens the size of the engine, greatly improves the effective load of the engine, and realizes the coverage (Ma2.5-15+) ultra-wide-domain flight;

(2) The invention uses the power combination form based on detonation combustion to lead the combustion chamber to have compact structure and small size, meets the requirements of the Rafael spray pipe in the rotary detonation combustion mode through the adjustable boss in the flow channel, is simultaneously used for triggering the inclined detonation combustion, has simple combination scheme design structure, does not need an additional extending structure in the flow channel, and effectively solves the problems of heat protection and combustion resistance under high Mach number;

(3) The truncated cone-shaped oblique knocking combustion organization scheme can realize the adaptation and transition with the rotary knocking combustion chamber, can realize two different knocking combustion modes in the same flow passage, and realizes the mode conversion between rotary knocking and oblique knocking;

(4) The invention adopts a multistage 'round platform' -shaped detonation configuration, solves the problems of difficult detonation and difficult residence of oblique detonation waves under low Mach number, can realize stable work of two detonation combustion modes under transitional working conditions, reduces the height of a runner, ensures the feasibility of a rotary detonation runner and reduces the size of an engine.

Drawings

FIG. 1 is a schematic view of a rotary detonation combustion mode flow channel (the tail end of an inner column is of a pointed cone structure), wherein I is an inlet channel compression section, 1 is an inlet channel, 3 is a spray pipe, 4 is an inner column, 5 is a shell, 2 is a rotary detonation mode combustion chamber, 21 is a fuel injection area, 22 is an annular combustion chamber section, and 23 is a rotary detonation spray pipe throat front area;

FIG. 2 is a schematic diagram of a rotary detonation and oblique detonation transition and oblique detonation combustion mode combustion chamber (a local part, a round table structure is arranged at the tail end of an inner column), wherein 3 is a spray pipe, 4 is an inner column, 5 is a shell, 21 is a fuel injection area, 22' is an oblique detonation fuel mixing section, and 23' is an oblique detonation induction initiation area (a runner is an oblique detonation mode combustion chamber 2 ') in the present invention;

FIG. 3 is a schematic view of the inner column structure of FIG. 2 (with the front cone removed), wherein 42 is a middle cylindrical section, 43 is an adjustable boss structure, and 44 is an end-pinch structure;

fig. 4 is a schematic diagram of a profile structure of an adjustable boss structure (an inner column structure form in fig. 2), fig. 4a is a rotary detonation combustion mode, wherein 44 is an end shrinkage structure, 43 is an adjustable boss structure (not classified in the rotary detonation combustion mode, each stage is the same inclination angle), fig. 4b is an oblique detonation combustion mode, wherein 44 is an end shrinkage structure, 431 and 432 are first-stage and second-stage adjustable classification structures, and 431 and 432 form a two-stage detonation device in the oblique detonation combustion mode;

FIG. 5 is an adjustment mechanism for an adjustable boss structure and end pinch structure of the present invention;

FIG. 6 is a simulated calculation verification result of the exemplary "engagement condition" (Ma6.5) declined detonation combustion verified by the embodiment of the present invention;

FIG. 7 is a flow chart of the combined knock of the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples and drawings.

As shown in fig. 1 and 2, the invention provides a combined detonation engine, which comprises an inner column 4 and a shell 5, wherein an annular flow passage is formed between the inner column 4 and the shell 5, the annular flow passage comprises an air inlet passage, a combustion chamber and a spray pipe, and the combined detonation engine realizes conversion transition of a rotary detonation combustion mode and an oblique detonation combustion mode by adjusting the annular flow passage along with continuous increase of a flight Mach number.

The combined detonation engine combustion modes of the present invention include a rotary detonation combustion mode and a diagonal detonation combustion mode. The rotary detonation combustion mode is shown in fig. 1, and the annular flow passage comprises an air inlet passage 1, a rotary detonation mode combustion chamber 2 and a spray pipe 3. The rotary detonation modal combustor 2 includes a fuel injection region 21, an annular combustor section 22, and a rotary detonation nozzle throat forward region 23.

The annular flow passage includes an inlet port, a fuel injection region 21, a cross-detonation fuel blending section 22' (annular combustion chamber section 22 in the rotary detonation combustion mode) and a cross-detonation induced detonation region 23' (cross-detonation mode combustion chamber 2 ') and a nozzle 3, as shown in fig. 2.

The invention adjusts the annular flow passage by adjusting the rear section structure of the inner column, thereby realizing the conversion of combustion modes. As shown in fig. 1,2 and 3, the inner column includes a front cone, a central cylindrical structure 42, a rear adjustable boss structure 43 and an end constriction 44.

The adjustable boss structure 43 is composed of at least two adjustable hierarchical structures, the inclination angle of each of which is adjustable, the length of each of which increases in turn along the direction of incoming flow, and each of which is a circular truncated cone structure. Preferably, the adjustable boss structure is 2-3 stages. Further preferably, the first stage adjustable stage has a length in the range of 0.05D to 0.15D and the last stage adjustable stage has a length in the range of 0.3D to 0.5D, D being the diameter of the inner column middle cylindrical structure 42.

As shown in fig. 4a, in the rotary detonation combustion mode, the adjustable boss structure 43 is of a primary structure, that is, the inclination angles of all the adjustable hierarchical structures of the adjustable boss structure 43 are the same, the adjustable boss structure 43 is of a circular truncated cone structure, and a rotary detonation nozzle throat is formed between the extreme end of the adjustable boss structure 43 and the housing 5.

In a transition stage of the rotary knocking combustion mode, namely a transition mode, the adjustable boss structure is converted from a primary structure to a multi-stage structure, the inclination angles of all stages of adjustable hierarchical structures of the adjustable boss structure are adjusted, and the inclination angles of all the adjustable hierarchical structures are sequentially reduced along the incoming flow direction.

Further preferably, the first stage adjustable hierarchical structure has an inclination angle ranging from 40 to 50 degrees, a length ranging from 0.05D to 0.15D, the last stage adjustable boss structure has an inclination angle ranging from 25 to 35 degrees, a length ranging from 0.3D to 0.5D, and D is the diameter of the middle cylindrical structure 42 of the inner column.

In the oblique detonation combustion mode, the adjustable boss structure is of a multi-stage structure, the lengths of the adjustable hierarchical structures of all stages are sequentially increased along the incoming flow direction, and the inclination angles are sequentially reduced. Preferably, the inclination angle range of the first-stage adjustable hierarchical structure is 30-40 degrees, the length range is 0.05-0.15D, the inclination angle range of the last-stage adjustable boss structure is 15-30 degrees, and the length range is 0.3-0.5D.

Further preferably, the specific number of steps, each level of inclination angle, length, etc. are selected in accordance with the initiation and residence of the detonation wave satisfying the inclination in the annular combustion chamber.

Taking two-stage adjustable boss structures as an example, as shown in fig. 1, when the flight Mach number is between Ma2.5 and Ma6, the engine is in a rotary detonation combustion mode, the adjustable boss structure 43 of the inner column is used as the throat of the Laval nozzle of the rotary detonation combustion chamber, the two-stage adjustable boss structure is in a one-stage structure, the two-stage angles are the same, and the specific nozzle throat size can refer to a traditional jet pipe design method of the scramjet engine.

When the flight Mach number is gradually increased to the second Mach number (Ma 6-Ma 7), the engine is in a connection working condition, the engine is in a truncated cone type oblique detonation combustion mode, and the adjustable boss structure is used as a detonation induction mechanism of oblique detonation combustion and is of an adjustable variable structure. As shown in fig. 2, the adjustable boss structure 43 of the inner column is composed of a first stage adjustable hierarchical structure 431 and a second stage adjustable hierarchical structure 432. Increasing the 431 tilt angle of the first stage adjustable hierarchy, decreasing the 432 tilt angle of the second stage adjustable hierarchy, and increasing the nozzle expansion ratio. Preferably, the first stage of adjustable hierarchical structure has an inclination angle alpha ₁ 40-50 DEG, length L ₁ The design of the detonation device is 0.05-0.15D, and the detonation device can accelerate detonation and can not cause direct detachment of the oblique detonation wave. The second stage adjustable hierarchical structure adopts a boss with smaller angle and longer length, so that the inclined detonation wave with slight detachment can be kept stationary again. Second-stage adjustable hierarchical structure inclination angle alpha ₂ 25-35 DEG, length L ₂ The design of the detonation gun is 0.3-0.5D, and the detonation and the residence of the detonation wave can be maintained.

When the flight Mach number continues to be increased to Ma 7-Ma 15, the engine is in a detonation combustion mode, and as shown in fig. 2, the angle adjustable range of the two-stage detonating device is correspondingly larger because the incoming flow speed is higher and the residence interval of detonation wave is larger. Preferably, the inclination angle range of the first-stage adjustable hierarchical structure is 30-40 degrees, and the inclination angle range of the second-stage adjustable boss structure is 15-30 degrees.

The rear section of the inner column adopts adjustable boss structures with different angles and lengths, the effects of the adjustable boss structures are different in different modes, and the adjustable boss structures are used as the contraction section of the rear Laval nozzle of the rotary detonation combustion chamber in the rotary detonation mode; in the oblique detonation mode, the adjustable boss structure is used as an oblique detonation wave induced detonation device.

The invention provides a design of large angle and small angle in the annular combustion chamber, and simultaneously, the fuel injection equivalent ratio is adjusted in time, so that the detonation and residence of oblique detonation waves in the annular combustion chamber can be realized, the effect of multi-stage 'round table' -shaped oblique detonation is achieved, and the problems that the oblique detonation combustion is difficult to detonate and residence due to lower static temperature and lower speed under the connection working conditions (Ma 6-7) are overcome. The first-stage oblique detonation initiating device adopts a boss with larger angle and shorter length, and can induce stronger oblique shock waves, so that the temperature and pressure of the wave after the wave are greatly improved. The circular truncated cone type oblique knocking refers to oblique knocking induced by a boss in an axisymmetric annular flow passage.

Further, the invention provides a driving mechanism (second stage) shown in fig. 5, which is installed in the inner column, under the low mach number of the linking working condition, the first driving mechanism (adjusting the first stage adjustable hierarchical structure) translates backwards, and the second driving mechanism (adjusting the second stage adjustable hierarchical structure) translates backwards, but the translation amplitude is smaller than that of the first driving mechanism, so as to ensure the formation of the detonation device configuration of 'large angle + small angle'. Meanwhile, the third driving mechanism (adjusting the tail end shrinkage structure) controls the expansion degree of the spray pipe, and when the third driving mechanism moves backwards, the rear part of the tail end shrinkage structure (corresponding to the flow passage is expanded) moves downwards, so that the spray pipe is expanded more, and the thrust requirement of the aircraft is met.

The adjustable boss structure is followed by a smooth transition terminal contraction structure, and is used as the expansion inner wall surface of the spray pipe in two modes, the structure is a known technology, a pointed cone or a round platform structure as shown in fig. 1 and 2 can be adopted, and the specific design can be seen from the adjustable spray pipe. Those skilled in the art can design the driving structure according to the actual situation to realize the adjustment of the adjustable boss structure and the terminal contraction structure of the present invention, and is not limited to the structure shown in fig. 5.

The middle section of the inner column is in a cylindrical structure with a fixed diameter, and the range [ D ] of the diameter D of the middle section of the inner column of the engine is determined according to the flow and thrust requirements of an aircraft and the rotary knocking principle _min ,D _max ]. In order to facilitate the detonation of the oblique detonation wave, the length of an induction area of the oblique detonation wave can be effectively shortened by utilizing the larger diameter of the inner pillar, the detonation is accelerated, and the detonation of the oblique detonation wave is realized under the condition of lower flow channel height. Preferably, the invention is within the range of inner column diameters [ D ] _min ,D _max ]Internal selection [ D ] _Z ,D _max ]As the diameter range of the middle cylindrical structure of the inner column of the present invention, D _Z ＞(D _min +D _max ) And/2 is the minimum value of the preferred range of inner column diameters.

Preferably, the height of the annular cavity between the outer wall of the inner column (middle cylindrical portion) and the inner wall of the housing is not more than 0.5D.

The front part of the inner column is of a rectifying cone structure, the front end of the shell is adjustable, and the compression degree of air inlet is adjusted through the adjustable front end of the shell so as to adapt to two combustion modes of rotary knocking and oblique knocking. The specific structure is known in the art, and can be seen from the design of the adjustable air inlet channel and the rectifying cone in the prior art.

As shown in fig. 1, in the rotary detonation combustion mode, the front rectifying cone is annular to enter air, the front end of the shell can adjust the compression degree of the air, after being compressed by the air inlet compression section i, the incoming flow enters the rotary detonation annular combustion chamber 2, and meanwhile, the fuel is injected from the head of the rotary detonation combustion chamber (the fuel injection area 21) and mixed with air to form rotary detonation combustion in the annular cavity. The combustion products in the annular cavity are expanded and discharged to do work through the Laval nozzle, and thrust is generated. As shown in fig. 2, in the oblique knocking combustion mode, the front intake air and compression are the same as in the rotary knocking combustion mode, and the operation of the oblique knocking engine is adapted by adjusting the compression degree of the intake air. After being compressed by the air inlet compression section I, the incoming flow enters the fuel injection area 21, and meanwhile, fuel is injected from the head of the oblique detonation combustion chamber, fully mixed in the oblique detonation fuel mixing section 22' (an annular cavity, namely the annular combustion chamber section 22 in a rotary detonation combustion mode), detonated by the oblique detonation induction detonation area 23' (the oblique detonation annular combustion chamber 2 ') to generate oblique detonation waves of a circular truncated cone shape, and expanded by the tail expansion spray pipe to generate thrust.

Further, as shown in fig. 1 and 2, a fuel injection region 21 of the present invention is provided at the head of the combustion chamber, and a plurality of fuel injection inlets are provided in the circumferential direction in the fuel injection region 21, and the position and length L of the fuel injection region are as follows _P The fuel injection inlet is designed according to the oblique knocking principle.

The injector of the fuel injection inlet can be in a small support plate injection or small cantilever beam injection scheme, so that the penetration depth of the injected fuel close to the annular outer wall surface and the uniformity of fuel distribution are improved, and the injected fuel and compressed air can be fully mixed in the annular channel.

Further preferably, to better organize the oblique detonation combustion, the oblique detonation fuel blending segment 22' length L for fuel mixing _C (annular combustion chamber section 22) is between 5D and 10D.

As shown in fig. 6, a typical "truncated cone" inclined knock simulation result under "engagement condition" (incoming flow ma 6.5) is provided, in which a certain section pressure contour line is distributed, and the simulation result shows that: the two-stage detonating device can realize detonation and residence of the oblique detonation wave under the 'connection working condition', and the feasibility of the invention is verified.

Further, the invention provides an aircraft adopting the combined detonation engine.

Still further, the present invention provides a method for combined knocking, as shown in fig. 7, comprising the steps of:

the detonation combustion mode is rotated.

In the first Mach number, the engine performs rotary detonation combustion, and the adjustable boss structure of the inner columnIs of a primary structure, namely the inclination angles of the adjustable hierarchical structures of all stages are consistent, and the inclination angles alpha of the adjustable boss structure under the rotary knocking mode are all the same _XZ 。

In the step, when the incoming flow Mach number is lower and is positioned in the first Mach number, the inlet section profile is adjusted to compress the incoming flow air to a certain degree, so that the compressed air and fuel are mixed and then are organized in the annular cavity to realize rotary knocking, the adjustable boss structure of the inner column is of a primary structure, and the Laval nozzle expands to do work after passing through the annular cavity.

In this step, the first Mach number is in the rotational knock operating range, which is generally referred to in the art as between Ma2.5 and Ma6.5+.

Further, in the rotary knock combustion mode in this step, the inclination angle α of the rotary knock boss _XZ Preferably obtained by a numerical simulation of the rotational knock, with specific reference to techniques known in the art of rotational knock design.

In the step, under the first Mach number, a jet pipe throat design is carried out by adopting a rotary detonation combustion principle, so that the inclination angle of the adjustable boss structure is determined. The nozzle throat height at the first Mach number is related to the Mach number and a range of tilt angle values for the adjustable boss structure corresponding to different Mach numbers are obtained.

Other rotary knock combustion aspects of this step are known in the art as rotary knock.

At the second Mach number, the engine transitions from a transitional mode, i.e., a rotary knock combustion mode to a diagonal knock combustion mode.

With the increase of Mach numbers, the inclination angles of the adjustable hierarchical structures of each stage of the adjustable boss structure are adjusted from the first Mach number to the second Mach number in a transition mode, so that the adjustable boss structure is converted from a primary structure to a multi-stage structure, and the inclination angles alpha of the adjustable hierarchical structures of each stage in the transition mode are along the incoming flow direction _Gi Sequentially decreasing, where i=1, 2, … n is the number of stages of the adjustable hierarchy.

Further, the inclination angle alpha of each stage of adjustable hierarchical structure under transition mode in the step _Gi The detonation of the oblique detonation wave is ensured under the second Mach number of the engine through the optimized acquisition of the oblique detonation numerical simulationWith resident, adjustable hierarchical structure inclination angle alpha of each level under transition mode _Gi In relation to Mach numbers, a series of stage-adjustable hierarchical inclinations alpha corresponding to different Mach numbers is obtained _Gi 。

Further preferably, the inclination angle alpha of each stage of the adjustable hierarchical structure _Gi The steps of the obtaining are as follows,

(1) And determining the length and the initial value of the inclination angle of each level of adjustable hierarchical structure.

Initial values of the length and the inclination angles of the adjustable hierarchical structures at all levels are preliminarily determined, and the requirements that the lengths of the adjustable hierarchical structures are sequentially increased and the inclination angles are sequentially reduced along the incoming flow direction are met.

Preferably, the initial value of the length of each stage of adjustable hierarchical structure is set as follows, the initial value of the length of the first stage of adjustable hierarchical structure ranges from 0.05D to 0.15D, the initial value of the length of the last stage of adjustable hierarchical structure ranges from 0.3D to 0.5D, the initial value of the length of the middle stage is selected between the first stage and the last stage, as long as the requirement that the lengths of all adjustable hierarchical structures sequentially increase along the incoming flow direction is met, wherein D is the diameter of the middle cylindrical structure of the inner column.

Preferably, the initial value of the inclination angle of each stage of adjustable hierarchical structure is set as follows, the initial value range of the inclination angle of the first stage of adjustable hierarchical structure is 40-50 degrees, the initial value range of the inclination angle of the last stage of adjustable boss structure is 25-35 degrees, the initial value of the inclination angle of the middle stage is selected between the first stage and the last stage, and the requirement that the inclination angles of all adjustable hierarchical structures are sequentially reduced along the incoming flow direction is met.

(2) And under the second Mach number, carrying out oblique knocking numerical simulation, and optimizing the inclination angles and the lengths of the adjustable hierarchical structures of all levels to obtain the optimal adjustable hierarchical structure lengths of all levels and the optimal adjustable hierarchical structure inclination angles of all levels related to the Mach number.

In this step, the obtained inclination angles of the adjustable hierarchies of the stages at the second Mach number are correlated with the Mach numbers, and a series of inclination angle values corresponding to different Mach numbers are obtained.

Further, the step of adjusting the adjustable boss structure includes adjusting an inclination angle alpha of the boss structure from a rotary detonation combustion mode _XZ Inclination angle alpha of each stage of adjustable hierarchical structure under transition mode _Gi Inclination angle alpha of each stage of adjustable hierarchical structure under transition and transition modes _Gi Inclination angle alpha of each stage of adjustable hierarchical structure under syncline detonation combustion mode _Xi And (5) transition.

In the step, the specific design of smooth transition of the inclination angles of the various stages of adjustable hierarchical structures under the mode conversion along with the increase of Mach numbers can be used for referencing the prior art of smooth transition of parameters in the mode conversion process of the engine in the field.

Further preferably, the inclination angle α of the first stage adjustable hierarchical structure _G1 The range is 40-50 degrees, and the inclination angle alpha of the nth-stage adjustable hierarchical structure is the same as the range _Gn The range is 25-35 degrees.

The second Mach number in this step is the "link mode", which is generally referred to as Ma 6-Ma 7.

The self-sustaining propagation of the rotary detonation wave is realized by adjusting the compression degree and the equivalence ratio of incoming flow, and the specific adjustment is referred to the rotary detonation design principle. The step also comprises the step of expanding and adjusting the spray pipe to meet the combustion requirement in the transitional mode. Other knock combustion content in this step is known in the art as rotary knock and oblique knock.

In the step, rotary detonation is transferred to oblique detonation, an adjustable boss structure is adjusted to a multi-stage structure from a one-stage structure under the second Mach number, and the blended fuel is detonated in the adjustable boss structure to form a truncated cone-shaped oblique detonation wave, and the rotary detonation is transferred to the oblique detonation.

The invention provides a multistage detonation device scheme of ' accelerating detonation of a shorter large-angle detonation device and maintaining the resident state of a longer small-angle detonation device ', wherein the large-angle detonation device can improve the temperature and pressure after oblique shock waves, can enable incoming flow mixed gas to reach a firing point, greatly shortens an induction area for detonation of oblique detonation waves, effectively reduces the length of oblique wedges ', but can not realize the resident state of oblique detonation waves by only adopting the large-angle detonation device, and can lead the detonation waves to be separated and forwarded due to lower incoming flow speed under a connecting working condition. Therefore, a shorter high-angle detonating device is adopted to perform the functions of heating, pressurizing and accelerating detonation, and a longer low-angle detonating device is used to maintain the residence of the detonation wave immediately after the high-angle detonating device. The combined detonation scheme can not only realize detonation and residence of the oblique detonation wave under the low Mach number, but also effectively reduce the height of the annular cavity, and realize perfect connection of two detonation combustion modes under different flight working conditions.

Further preferably, the adjustable boss structure (the induction device for inducing the inclined knocking in the annular cavity) is arranged by adopting the two-stage detonation device, so that the height of the runner can be greatly reduced to match the requirement of the rotary knocking combustion structure, and meanwhile, the movable of the connecting point of the two-stage detonation device is driven by the driving mechanism capable of horizontally moving on the inner side of the inner column to realize the variable adjustment of the angle of the two-stage detonation device, so that the requirement of an aircraft under different flight working conditions is met, and the resistance is effectively reduced while the thrust is generated.

Oblique knocking combustion mode.

Under the third Mach number, the adjustable boss structure is of a multi-stage structure, and the blended fuel detonates in the multi-stage adjustable boss structure to form a truncated cone-shaped oblique detonation wave for oblique detonation combustion.

In the step, as Mach number continues to increase, a third Mach number is entered, the adjustable boss structure is of a multi-stage structure, and inclination angles alpha of all stages of adjustable hierarchical structures in a diagonal detonation combustion mode are along the incoming flow direction _Xi Sequentially decreasing, where i=1, 2, … n is the number of stages of the adjustable hierarchy.

Further preferably, the inclination angle alpha of each stage of the adjustable hierarchical structure _Xi The steps of the obtaining are as follows,

(1) And determining the initial value of the inclination angle of each level of adjustable hierarchical structure.

Initial values of inclination angles of all levels of adjustable hierarchical structures are preliminarily determined, and the requirement that the inclination angles of all adjustable hierarchical structures are sequentially reduced along the incoming flow direction is met.

Preferably, the initial value of the inclination angle of each stage of adjustable hierarchical structure is set as follows, the initial value range of the inclination angle of the first stage of adjustable hierarchical structure is 30-40 degrees, the initial value range of the inclination angle of the last stage of adjustable boss structure is 15-30 degrees, the initial value of the inclination angle of the middle stage is selected between the first stage and the last stage, and the requirement that the inclination angles of all adjustable hierarchical structures are sequentially reduced along the incoming flow direction is met.

(2) And under the third Mach number, carrying out oblique knocking numerical simulation, and optimizing the inclination angles of the adjustable hierarchical structures at all levels to obtain the optimal inclination angles of the adjustable hierarchical structures at all levels related to the Mach number.

Further, in the step, the inclination angle alpha of each stage of the hierarchical structure can be adjusted under the inclined detonation combustion mode _Xi The detonation and residence of the oblique detonation wave of the engine under the third Mach number is ensured by the optimized acquisition of the oblique detonation numerical simulation, and the inclination angle alpha of each stage of adjustable hierarchical structure under the oblique detonation combustion mode _Xi In relation to the mach number, a series of dip values corresponding to different mach numbers are obtained.

In the step, when the incoming flow Mach number is higher and is positioned in the third Mach number range, the proper compression degree of the incoming air is adjusted, the annular cavity of rotary detonation is used as a fuel blending section necessary for the inclined detonation combustion structure, an adjustable boss structure is used as a detonation device of inclined detonation combustion, no extra extension device is needed, and an inner column boss of the rotary detonation mode used for shrinkage of the Laval nozzle is used as a detonation device of inclined detonation wave, which is different from a common oblique-induced binary combustion chamber structure. The oblique detonation combustion chamber is an axisymmetric combustion chamber, can perform oblique detonation combustion in a circular truncated cone-shaped structure of the annular combustion chamber, does work through expansion of the tail nozzle, and can rapidly release heat in a very short distance to generate thrust.

Further, the third Mach number is in the oblique knock operating range, which is generally referred to in the art as between Ma6.5 and Ma15+.

Further preferably, the inclination angle α of the first stage adjustable hierarchical structure _X1 The range is 30-40 degrees, and the inclination angle alpha of the nth stage adjustable boss structure is the same as the range of 30-40 degrees _Xn The range is 15-30 degrees.

The step also comprises the adjustment of the compression degree of the incoming flow and the expansion ratio of the spray pipe, so as to meet the requirements of oblique detonation combustion. Other diagonal knock combustion aspects of this step are known in the art as diagonal knock.

The invention is not described in detail in a manner known to those skilled in the art.

Claims (16)

1. A combination detonation engine, includes interior post and shell, forms annular runner, its characterized in that between interior post and the shell: the inner column is provided with an adjustable boss structure, the adjustable boss structure is composed of at least two adjustable hierarchical structures, and the lengths of the adjustable hierarchical structures are sequentially increased along the incoming flow direction;

the inclination angles of the adjustable hierarchical structures are consistent under the rotary detonation combustion mode, mach numbers are increased to the second Mach number, the inclination angles of the adjustable hierarchical structures are adjusted to enable the inclination angles of the adjustable hierarchical structures to be sequentially reduced along the incoming flow direction, the adjustable boss structures induce detonation and oblique detonation, the engine is converted from the rotary detonation combustion mode to the oblique detonation combustion mode, and the inclination angles of the adjustable hierarchical structures are sequentially reduced along the incoming flow direction under the oblique detonation combustion mode.

2. The combination knock engine of claim 1, wherein: the number of the adjustable hierarchical structures is 2-3.

3. The combination knock engine of claim 1, wherein: the length of the first stage of the adjustable hierarchical structure is 0.05D-0.15D, and the length of the last stage is 0.3D-0.5D, wherein D is the diameter of the middle part of the inner column.

4. The combination knock engine of claim 1, wherein: the inclination angle range of the first stage is 40-50 degrees, and the inclination angle range of the final stage is 25-35 degrees under the rotary detonation combustion mode of the adjustable grading structure.

5. The combination knock engine of claim 1, wherein: the annular flow passage comprises an air inlet passage, a combustion chamber and a spray pipe, the combustion chamber comprises a fuel injection area, an annular combustion chamber section and a rotary detonation spray pipe throat front area in a rotary detonation combustion mode, the annular combustion chamber section is used as an inclined detonation fuel blending section in an inclined detonation combustion mode, and the rotary detonation spray pipe throat front area is converted into an inclined detonation induction detonation area through inclination angle adjustment of each adjustable hierarchical structure.

6. The combination knock engine of claim 1, wherein: the inclination angle range of the first stage is 30-40 degrees, and the inclination angle range of the final stage is 15-30 degrees under the inclined detonation combustion mode.

7. The combination knock engine of claim 2, wherein: the middle part of the inner column is of a cylindrical structure, and the diameter range of the middle part of the inner column is [ D ] _Z ,D _max ]，D _Z ＞(D _min +D _max ) 2, wherein D _min 、D _max The diameter D of the middle section of the inner column is the minimum value and the maximum value determined according to the principle of rotary knocking.

8. The combination knock engine of claim 5, wherein: the length L of the inclined knocking fuel mixing section _C The height of the annular cavity of the annular combustion chamber section is not more than 0.5D and is 5D-10D.

9. The combination knock engine of claim 1, wherein: the device also comprises a driving mechanism for adjusting the dip angle of the adjustable hierarchical structure, wherein the driving mechanism is arranged inside the inner column.

10. An aircraft employing the combined detonation engine of any of the preceding claims.

11. A method of combined detonation, comprising the steps of:

the mode of knocking combustion is rotated,

in the first Mach number, the engine carries out rotary detonation combustion, and the inclination angles of all stages of adjustable hierarchical structures of the adjustable boss structure are consistent and are the inclination angles alpha of the adjustable boss structure under the rotary detonation mode _XZ ；

The transition mode is carried out in such a way that,

the Mach number is increased to a second Mach number, the inclination angles of all levels of adjustable hierarchical structures of the adjustable boss structures are adjusted, and the inclination angles alpha of all levels of adjustable hierarchical structures in the transitional mode along the incoming flow direction are enabled _Gi Sequentially reducing, and converting the engine from a rotary knocking combustion mode to a diagonal knocking combustion mode, wherein i=1, 2 and … n are the stages of the adjustable hierarchical structure;

the combustion mode of the oblique knocking is that,

mach number is increased to a third Mach number, and inclination angle alpha of each stage of adjustable hierarchical structure under oblique detonation combustion mode along incoming flow direction _Xi And sequentially reducing, detonating the blended fuel in the adjustable boss structure to form oblique detonation wave, and performing oblique detonation combustion, wherein i=1, 2 and … n are the stages of the adjustable hierarchical structure.

12. The combination knock method of claim 11, wherein: the transition mode, the adjustment of the adjustable boss structure comprises the adjustment of the inclination angle alpha of the boss structure from the rotary knocking combustion mode _XZ Inclination angle alpha of each stage of adjustable hierarchical structure under transition mode _Gi Inclination angle alpha of each stage of adjustable hierarchical structure under transition and transition modes _Gi Inclination angle alpha of each stage of adjustable hierarchical structure under syncline detonation combustion mode _Xi And (5) transition.

13. The combination knock method of claim 12, wherein: the inclination angle alpha of the rotary knocking boss _XZ The inclination angle alpha of each stage of adjustable hierarchical structure under the transition mode is preferably obtained through rotary knock numerical simulation _Gi The inclined detonation value simulation is preferably obtained, and the inclined angle alpha of each stage of the adjustable hierarchical structure under the inclined detonation combustion mode is obtained _Xi Preferably obtained by means of a simulation of the value of the knocking.

14. The combination knock method of claim 13, wherein: the first-stage inclination angle alpha of the adjustable hierarchical structure under the transition mode _G1 The range is 40-50 degrees, and the n-th level dip angle alpha is _Gn The range is 25-35 DEGThe first-stage inclination angle alpha of the adjustable hierarchical structure in the inclined detonation combustion mode _X1 The range is 30-40 degrees, and the n-th level dip angle alpha is _Xn The range is 15-30 degrees.

15. The combination knock method of claim 11, wherein: the first Mach number is a rotary knocking working range, the second Mach number is a 'linking working condition' between the rotary knocking working range and the inclined knocking working range, and the third Mach number is the inclined knocking working range.

16. The combination knock method of claim 11, wherein: the rotary detonation combustion mode, the transition mode and the oblique detonation combustion mode further comprise adjustment of incoming flow compression degree, equivalence ratio and jet pipe expansion ratio.

Images