CN111779592A - Mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers - Google Patents

Mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers Download PDF

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Publication number
CN111779592A
CN111779592A CN202010485871.2A CN202010485871A CN111779592A CN 111779592 A CN111779592 A CN 111779592A CN 202010485871 A CN202010485871 A CN 202010485871A CN 111779592 A CN111779592 A CN 111779592A
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China
Prior art keywords
fan
air
combustion chamber
inner duct
mixer
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CN202010485871.2A
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Chinese (zh)
Inventor
徐国强
孙京川
闻洁
全永凯
郭昆
庄来鹤
刘启航
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Beihang University
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Beihang University
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Priority to CN202010485871.2A priority Critical patent/CN111779592A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K3/00—Plants including a gas turbine driving a compressor or a ducted fan
    • F02K3/08—Plants including a gas turbine driving a compressor or a ducted fan with supplementary heating of the working fluid; Control thereof
    • F02K3/105—Heating the by-pass flow
    • F02K3/11—Heating the by-pass flow by means of burners or combustion chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
    • F02C3/14—Gas-turbine plants characterised by the use of combustion products as the working fluid characterised by the arrangement of the combustion chamber in the plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/38—Introducing air inside the jet
    • F02K1/386—Introducing air inside the jet mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K3/00—Plants including a gas turbine driving a compressor or a ducted fan
    • F02K3/02—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber
    • F02K3/04—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type
    • F02K3/06—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type with front fan

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

The invention relates to the field of aviation industry energy power machinery, in particular to a mixed exhaust turbofan engine propulsion system introducing a parallel combustion chamber, which can improve the thrust characteristic of the turbofan engine and specifically comprises an inner duct formed from a fan to a mixer; an outer duct is formed from the fan to the mixer; a high-pressure compressor and a first combustion chamber are arranged on the inner duct; the high-pressure air machine and the first combustion chamber are sequentially connected to the downstream of the fan; when the fan works, external air can be sucked from the air inlet channel, and the external air is pressurized by the high-pressure air machine to form first air, so that part of the first air moves along the flow direction of the inner duct; in addition, the outside air can enter the outer duct from the fan, so that another part of the outside air can reach the mixer; so that the outside air can enter the second combustion chamber when traveling in the direction of the bypass flow. From an energy perspective, the system is capable of transferring internal energy of the fuel to the bypass to increase exhaust temperature.

Description

Mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers
Technical Field
The invention relates to the technical field of aviation industry energy power systems, in particular to a mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers.
Background
In the current mode of the aviation industry energy power system, a widely accepted mode is to adopt a Brayton cycle, and the Brayton cycle has the characteristics of high flexibility, reliability, simple structure and high starting and loading speeds, so the Brayton cycle is widely used in the current mode and is a reliable technology of the aviation power system.
At present, the performance of the traditional turbofan engine based on the Brayton cycle is close to the theoretical limit thereof due to the limits of technology and materials. Given the ever-increasing demands placed on engine thrust or economy by existing aircraft, the subject of research and development work has tended to suggest various modified brayton cycles to meet specific thrust in order to strike a balance between economy and availability.
For example, in the turbofan engine, mainly for improving the economy, such as the interstage combustion, the precooling cycle, the intercooling regenerative cycle, and the like, the research on the breakthrough of the upper limit of the thrust is less. As aircraft maneuverability further increases, the specific thrust requirements for aircraft engines further increase. The existing main mode for improving the unit thrust is to improve the temperature in front of a turbine or adopt an afterburner, however, the temperature in front of the turbine is limited by the material and the design level of turbine blades of an engine, and the problems of unstable combustion, low combustion efficiency and the like exist in secondary oil injection combustion after the afterburner. In summary, how to further improve the specific thrust of the turbofan engine under the prior art becomes the focus of research on the prior aeroengine.
Disclosure of Invention
The present invention is directed to solving the prior art patent of the present invention is an improved system in the construction of a conventional turbofan engine based on the brayton cycle, which is a mixed exhaust turbofan engine propulsion system incorporating parallel combustion chambers. The problem that the temperature of gas in front of a turbine is too high and other parts cannot bear due to the fact that the specific thrust of the turbofan engine is improved is solved, the defects of unstable combustion and low combustion rate due to the fact that a secondary combustion method is adopted are overcome, and the thrust characteristic of the turbofan engine is further improved.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a mixed exhaust turbofan engine propulsion system incorporating parallel combustion chambers, comprising:
forming an inner duct from a fan to a mixer;
an outer duct is formed from the fan to the mixer;
a high-pressure compressor and a first combustion chamber are arranged on the inner duct;
the high-pressure air engine and the first combustion chamber are sequentially connected to the downstream of the fan;
when the fan works, external air can be sucked from the air inlet channel, and the high-pressure air engine is used for pressurizing the external air to form first air, so that part of the first air moves along the flow direction of the inner duct;
when the fan works, outside air can be sucked from the air inlet channel, and the outside air can enter the outer duct from the fan, so that the other part of the outside air can reach the mixer; and
a second combustion chamber;
the second combustion chamber is disposed on the bypass such that the outside air may enter the second combustion chamber as it travels in the direction of the bypass flow.
In particular, the endoprosthesis comprises:
and the first end of the inner duct second communicating part is communicated with the fan outlet, and the second end of the inner duct second communicating part is communicated with the inlet of the high-pressure compressor.
Specifically, the endoprosthesis further comprises:
and the first end of the inner duct third communicating part is communicated with the outlet of the high-pressure air engine, and the second end of the inner duct third communicating part is communicated to the inlet of the first combustion chamber.
In particular, the bypass comprises:
a first external communication portion, the fan having a fan diverging end, a first end of the first external communication portion communicating with the fan diverging end such that the fan is communicable with the external duct;
the second end of the first external communication portion communicates with the first end of the second combustion chamber.
In particular, the bypass further comprises:
a second external communication portion, the mixer having a mixer access, a second end of the second external communication portion communicating with the mixer access such that the mixer is communicable with the external duct;
a first end of the second external communication portion communicates with a first end of the second combustion chamber.
Further, downstream of the first combustion chamber, and in the direction of the inner duct flow, there are also sequentially provided: a high pressure turbine and a low pressure turbine;
downstream of the low pressure turbine is the mixer.
Particularly, the device also comprises a tail nozzle;
the tail nozzle is communicated with the second end of the mixer through a seventh inner duct connecting part positioned in the flow direction of the inner duct.
The invention has the following beneficial effects:
first, compared to the propulsion system of a conventional turbofan engine, the system of the present application is characterized by introducing a second combustion chamber in the outer duct to allow the airflow of the outer duct to participate in combustion. In the original system, aviation kerosene is used as the only energy source of the whole system, and in order to increase the exhaust temperature of the tail nozzle and increase the specific thrust, the use amount of fuel is increased essentially to achieve the aim.
Secondly, the temperature of the air after the air is subjected to adiabatic compression by the high-pressure compressor is higher, and due to the limitation of the temperature of the gas in front of the turbine, excessive aviation kerosene cannot be combusted in the main combustion chamber, and the afterburner cannot work continuously.
And thirdly, the improved system adds a second combustion chamber in the outer duct to directly heat the airflow of the outer duct and increase the exhaust temperature after mixing with the inner duct fuel gas. The improved system is energetically speaking, i.e., directly transfers increased internal fuel energy to the bypass air to increase exhaust temperature.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a system block diagram of a hybrid exhaust turbofan engine propulsion system incorporating parallel combustion chambers according to the present invention.
FIG. 2 is a T-S diagram of an ideal cycle of a working medium of a propulsion system of a mixed exhaust turbofan engine introduced into parallel combustion chambers.
The reference numerals in the figures denote:
the air inlet 100, the fan 200, the high-pressure compressor 300, the first combustion chamber 400, the second combustion chamber 410, the high-pressure turbine 500, the low-pressure turbine 600, the mixer 700 and the tail nozzle 800;
an inner duct 28, an outer duct 29, a first outer communicating portion 10, a second outer communicating portion 9;
the device comprises an initial position 0, an inner duct first connecting part 1, an inner duct second connecting part 2, an inner duct third connecting part 3, an inner duct fourth connecting part 4, an inner duct fifth connecting part 5, an inner duct sixth connecting part 6, a seventh inner duct connecting part 7 and a tail nozzle connecting part 8.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
For convenience of description, terms such as "first end", "second end", and the like used in this application to describe the relative positional relationship are used, and "left side" in the flow direction in the current view is taken as "first end" and "right side" is taken as "second end"; and the upper part of the current view is used as a first end, and the lower part of the current view is used as a second end; it is to be understood that the use of the above-described words is not to be construed as an undue limitation on the scope of protection.
Compared with the traditional turbofan engine propulsion system, the improved characteristics of the application are as follows: a second combustion chamber 410 is introduced in the outer duct 29, letting the gas flow of the outer duct 29 participate in the combustion. In the original system, aviation kerosene is used as the only energy source of the whole system, and in order to increase the exhaust temperature of the tail nozzle 800 and increase the specific thrust, the use amount of fuel is increased substantially to achieve the aim. However, the air is at a higher temperature after adiabatic compression by the high pressure compressor 300, which results in the failure to burn too much aviation kerosene in the main combustor due to the gas temperature limitation before the turbine, while the afterburner is not allowed to operate continuously. The improved system adds a second combustion chamber 410 in the outer duct to directly heat the gas flow in the outer duct 29, which is equivalent to the direct heating of the first gas, and increase the exhaust temperature after mixing with the gas in the inner duct 28. The present application, from an energy perspective, directly transfers the increased internal fuel energy to the bypass 29 air to increase exhaust temperature.
The operation of each main component and structure in the system is as follows:
specifically, the intake duct 100 being located at the forward most end of the propulsion system of the mixed exhaust turbofan engine, the forward most end corresponding to the initial position 0, is a section of the duct through which the outside air passes from the inlet on the aircraft to the inlet of the engine. After the outside air is sucked, the air inlet duct 100 decelerates and pressurizes the outside air with a high mach number, thereby reducing the total pressure loss as much as possible and satisfying the air inlet speed requirement of the fan 200.
Specifically, fan 200 is an improved variation of the propeller of a turboprop engine, i.e., shortening the diameter of the propeller, increasing the number of blades, and containing all the blades of the blades within the case. The fan 200 draws in a large amount of outside air and pressurizes the air compression. The compressed ambient air flow is divided into two streams, one entering the inner duct 28 for further work by the subsequent core engine and one entering the outer duct 29.
Specifically, in the high-pressure compressor 300, the high-pressure compressor 300 compresses an air flow by using blades rotating at a high speed to do work, so that the air flow is changed into a high-pressure gas. The high pressure compressor 300 is required to meet the design requirements of vibration strength and rigidity, good anti-surge performance, wide stable working range and the like.
Specifically, a first combustion chamber 400, the first combustion chamber 400 being a device capable of converting chemical energy of a fuel into thermal energy; the aviation fuel is combusted in the combustion chamber to release heat, so that the gas flow of the inner duct 28 from the heat exchanger is heated into high-temperature and high-pressure gas to meet the work requirement of a subsequent turbine. The combustion chamber needs rapid ignition and start-up, stable flame, higher combustion efficiency and small total pressure loss.
Specifically, the second combustion chamber 410, which is equivalent to a parallel combustion chamber, the second combustion chamber 410 is also a device capable of converting the chemical energy of the fuel into thermal energy. The aviation fuel is combusted in the combustion chamber to release heat, so that the airflow of the outer duct 29 is heated into high-temperature and high-pressure gas, and the high-temperature and high-pressure gas is mixed with the gas at the outlet of the low-pressure turbine 600, and the purpose of improving the thrust is achieved. The second combustion chamber 410 requires rapid ignition and start-up, a stable flame, high combustion efficiency, and low total pressure loss.
Specifically, the high-pressure turbine 500, the high-temperature and high-pressure combustion gas from the first combustion chamber 400, impacts the high-pressure turbine 500, converts the enthalpy of the combustion gas into the mechanical work of the turbine, and drives the coaxial high-pressure compressor 300 to rotate. Because the heat end component is adopted, the heat end component has the design requirements of high work conversion efficiency, small size, enough stable working range, reliable working under the conditions of high temperature and high rotating speed and the like.
Specifically, the low-pressure turbine 600, which has a high pressure and a high temperature after impacting the high-pressure turbine 500, can still impact the low-pressure turbine 500 to work, and drive the coaxial fan 200 to rotate. Because the temperature and pressure of the combustion gases become lower, the low pressure turbine 600 design requirements may be lower than the high pressure turbine 500 design requirements.
Specifically, mixer 700 blends the bypass high temperature, high pressure gas exiting the turbine with the bypass low temperature, low pressure gas stream.
Specifically, the tail nozzle 800, is an exhaust system of the engine, and further expands the high-temperature gas at the outlet of the turbine group, and converts the high enthalpy of the gas into kinetic energy, so that the gas is discharged at a high speed to generate thrust. The design requirements of small flow loss, complete expansion as much as possible, axial direction of the ejected airflow as much as possible and the like need to be met.
The specific implementation mode of applying the components to the mixed exhaust turbofan engine propulsion system with the parallel combustion chambers is as follows:
referring to FIG. 1, a mixed exhaust turbofan engine propulsion system incorporating parallel combustion chambers includes: forming an inner duct 28 from a fan 200 to a mixer 700; an outer duct 29 is also formed from the fan 200 to the mixer 700; a high-pressure compressor 300 and a first combustion chamber 400 are arranged on the inner duct 28; the high-pressure air engine 300 and the first combustion chamber 400 are connected to the downstream of the fan 200 in sequence;
when the fan 200 is in operation, external air may be sucked from the air inlet 100, and the high pressure air engine 300 may pressurize the external air to form a first gas, so that a portion of the first gas may travel along the flow direction of the inner duct 28;
wherein, when the fan 200 is operated, the external air can be sucked from the air inlet 100, and the external air can enter the bypass 29 from the fan 200, so that another part of the external air can reach the mixer 700; and a second combustion chamber 410;
the second combustion chamber 410 is arranged in the bypass 29 such that the outside air can enter the second combustion chamber 410 when traveling in the flow direction of the bypass 101.
Referring to fig. 1, the endoprosthesis 28 includes: the first end of the second communicating portion 2 of the inner duct communicates with the outlet of the fan 200, and the second end communicates with the inlet of the high pressure compressor 300.
Referring to fig. 1, the inner duct 28 further includes: the first end of the inner duct third communicating portion 3 communicates with the outlet of the high pressure engine 300, and the second end thereof communicates with the inlet of the first combustion chamber 400.
Referring to fig. 1, the bypass 101 includes: a first external communication portion 10, the fan 200 having a fan diverging end, a first end of the first external communication portion 10 communicating with the fan diverging end so that the fan 200 can communicate with the bypass 101; the second end of the first external communication portion 10 communicates with the first end of the second combustion chamber 410.
Referring to fig. 1, the bypass 29 further includes: a second external communication portion 9, said mixer 700 having a mixer inlet, a second end of said second external communication portion 9 communicating with said mixer inlet so that said mixer 700 can communicate with said external duct 101; a first end of the second external communication portion 11 communicates with a first end of the second combustion chamber 410.
Referring to fig. 1, downstream of the first combustion chamber 400, in the flow direction of the inner duct 28, there are further sequentially disposed: a high-pressure turbine 500 and a low-pressure turbine 600; downstream of the low pressure turbine 600 is the mixer 700.
Referring to FIG. 1, a jet nozzle 800 is also included; the jet nozzle 800 communicates with the second end of the mixer 700 via a seventh bypass connection 7 in the direction of the flow of the bypass 28.
Through the content, the use amount of aviation fuel can be increased more reasonably, meanwhile, the phenomenon that the turbine blades are seriously hot-corroded due to overhigh temperature in front of the high-pressure turbine 500 is avoided, the specific thrust of the engine is improved, the thrust characteristic of the turbofan engine is improved, and the system can transmit the internal energy of the fuel to the outer duct from the energy perspective, so that the exhaust temperature is improved.
The system further comprises: the air inlet 100, the fan 200, the high-pressure compressor 300, the first combustion chamber 400, the second combustion chamber 410, the high-pressure turbine 500, the low-pressure turbine 600, the mixer 700 and the tail nozzle 800;
an initial position 0, which corresponds to an inlet of the air inlet 100 for sucking the external air; the fifth and sixth endoprosthesis connection portions 5, 6 connect the high-pressure turbine 500 and the low-pressure turbine 600 downstream of the first combustion chamber 400; the tail nozzle connection portion 8 corresponds to a working end that generates thrust.
With reference to fig. 1 and 2, an initial position 0, a first inner duct connecting portion 1, a second inner duct connecting portion 2, a third inner duct connecting portion 3, a fourth inner duct connecting portion 4, a fifth inner duct connecting portion 5, a sixth inner duct connecting portion 6, a seventh inner duct connecting portion 7, a tail pipe connecting portion 8, a first outer connecting portion 10 and a second outer connecting portion 9 are shown;
referring to fig. 1 and fig. 2, the ideal cycle T-S diagram process of the working medium of the system is shown in attached table 1;
attached table 1 process relation of working medium ideal cycle T-S diagram of system
Relationships between parts Process code Process relationships
Initial position 0 to the first connection 1 of the inner duct 0-1 Adiabatic compression
The first connecting part 1 of the inner culvert to the second connecting part 2 of the inner culvert 1-2 Adiabatic compression
Second communicating part 2 of inner duct to third communicating part 3 of inner duct 2-3 Adiabatic compression
The third connecting part 3 of the inner culvert to the fourth connecting part 4 of the inner culvert 3-4 Heating under constant pressure
Fourth connecting part 4 of inner duct to fifth connecting part 5 of inner duct 4-5 Adiabatic expansion
Fifth connecting part 5 of inner duct to sixth connecting part 6 of inner duct 5-6 Adiabatic expansion
Sixth to seventh inner culvert connecting portions 6 to 7 6-7 Constant pressure heat release (heating)
Inner duct second communicating portion 2 to second outer communicating portion 9 2-9 Heating under constant pressure
Second external communication portion 9 to seventh internal duct connecting portion 7 9-7 Constant pressure heating (exothermic)
Exhaust nozzle connection 8 to second outer connection 9 8-9 Adiabatic expansion
Second external communication portion 9 to initial position 0 9-0 Constant pressure heat release
The circulation process of the system is described with reference to fig. 2 based on the attached table 1, and the technical effects that can be achieved by the present application are described by an embodiment;
the mass flow of air entering the inlet 100 is preset to q0Wherein the mass flow of the outer duct 29 is q1The mass flow of the inner duct 28 is q2The mass of the fuel after combustion is ignored. The temperature of the air flow entering the inner duct 28 is changed into T after being compressed by the fan 200 and the high-pressure compressor 3003。
Wherein the temperature T2 of the gas stream in the bypass 29 remains unchanged if the second combustion chamber 410 is not introduced.
The temperature of the airflow in the inlet inner culvert 28 is T3Enters the first combustion chamber 400 and is heated to T4In this case, the fuel is combusted in the first combustion chamber 400 to release heat, and there are:
Huqf＝CP,a(q1+qf)(T4-T3) (1)
in the above formula (1), HuThe heat of combustion, q, per unit mass of fuelfMass of fuel participating in combustion in the first combustion chamber, CP,aIs the heat capacity of air, q1For the purpose of entering the air quality of the connotation, T4For turbine front gas temperature, T3Is the air temperature before the first combustion chamber 400.
In a particular embodiment, the main combustion outlet temperature is preset to be T by the solution of the present application4With the second combustion chamber 410, the temperature of the gas entering the bypass 29 is T2, and the gas entering the second combustion chamber 410 is heated to T9At this time, the fuel is combusted in the second combustion chamber 410The combustion of the material gives off heat, and comprises:
Huq′f＝CP,a(q2+q′f)(T9-T2) (2)
in the above formula (2), HuIs the combustion calorific value, q 'of the fuel per unit mass'fMass of fuel participating in combustion in parallel combustion chambers, CP,aIs the heat capacity of air, q2Quality of air for admission to culvert, T9For the temperature of the gas at the outlet of the parallel combustion chamber, T2Is the second combustion chamber 410 inlet air temperature.
qf+q′f>qfThis shows that the solution of the present application can increase the amount of fuel used.
The high-temperature high-pressure air flow from the first combustion chamber 400 impacts the high-pressure turbine 500, the low-pressure turbine 600 drives the fan 200 and the high-pressure compressor 300 to do work, and then the temperature is changed into T6The temperature of the mixed gas entering the mixer 700 and the outer duct 29 is changed into T after being mixed with each other7. Assuming no introduction of the second combustion chamber 410, the temperature T of the gas flow in the bypass 292If the value is kept unchanged, the following steps are provided:
T7＝((q1+qf)T6+q2T2)/(q1+q2+qf) (3)
and the temperature T of the airflow in the bypass 29 is the second combustion chamber 4102Rising to the temperature T of the airflow of the outer duct 299Then, there are:
T′7＝((q1+qf)T6+(q2+q′f)T9)/((q1+q2+qf)+q′f) (4)
the combination of the formulas (3) and (4) indicates that T is2<T9The fuel flow is small and can be ignored. So T'7>T7. This demonstrates that the solution of the present application can increase the exhaust gas temperature.
According to the thrust formula of the mixed-exhaust turbofan engine:
F＝q8V8-q0V0+(P8-P0)A8(5)
in the above formula (5), q8Is the gas mass flow of the exhaust outlet cross section, q0Is the air mass flow, V, of the cross section of the air inlet8Is the gas outlet velocity, V0Is the air inlet velocity, P8For exhaust outlet static pressure, P0For inlet static pressure, A8Is the outlet cross-sectional area.
According to the relation between the local sound velocity and the Mach number:
Figure BDA0002519038720000091
in the above formula (6), MaMach number of the gas outlet section, k is the gas adiabatic index, R is the gas constant, T8Is the static temperature of the exhaust gas at the outlet section.
The combination of the formulas (5) and (6) shows that when the exhaust temperature T is higher8Increasing, with the remaining conditions remaining unchanged, by increasing the outlet exhaust velocity V9And improve engine thrust to realize the technological effect that this application will reach.
The process and effectiveness of the specific implementation mode of the invention are detailed and demonstrated by combining working medium working state examples of the whole flow chart. From the energy perspective, the scheme is that internal energy of increased fuel usage is directly transferred to the outer bypass air, so that exhaust temperature is improved, engine thrust is improved, and the problems of unstable combustion, low combustion efficiency and the like caused by overhigh temperature in front of a turbine and secondary heating are avoided.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (7)

1. A mixed exhaust turbofan engine propulsion system incorporating parallel combustion chambers, comprising:
forming an inner duct (28) from a fan (200) to a mixer (700);
-forming an outer duct (29) from said fan (200) to said mixer (700);
a high-pressure compressor (300) and a first combustion chamber (400) are arranged on the inner duct (28);
the high-pressure air engine (300) and the first combustion chamber (400) are connected to the downstream of the fan (200) in sequence;
when the fan (200) works, the external air can be sucked from the air inlet channel (100), and the high-pressure air engine (300) pressurizes the external air to form first air, so that part of the first air advances along the flow direction of the inner duct (28);
wherein, when the fan (200) is in operation, ambient air can be sucked in from the air inlet (100), and the ambient air can enter the bypass (29) from the fan (200) so that another part of the ambient air can reach the mixer (700); and
a second combustion chamber (410);
the second combustion chamber (410) is arranged on the bypass (29) such that the ambient air can enter the second combustion chamber (410) when travelling in the flow direction of the bypass (29).
2. The mixed exhaust turbofan engine propulsion system introducing parallel combustors as recited in claim 1 wherein said inner duct (28) comprises:
and the first end of the inner duct second communication part (2) is communicated with the outlet of the fan (200), and the second end of the inner duct second communication part is communicated with the inlet of the high-pressure compressor (300).
3. The mixed exhaust turbofan engine propulsion system introducing parallel combustors as recited in claim 2 wherein said inner duct (28) further comprises:
and the first end of the inner duct third communication part (3) is communicated with the outlet of the high-pressure air engine (300), and the second end of the inner duct third communication part is communicated with the inlet of the first combustion chamber (400).
4. The mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers of claim 3 wherein the outer duct (29) comprises:
a first external communication portion (10), the fan (200) having a fan diverging end, a first end of the first external communication portion (10) communicating with the fan diverging end so that the fan (200) can communicate with the bypass (29);
the second end of the first external communication portion (10) communicates with the first end of the second combustion chamber (410).
5. The mixed exhaust turbofan engine propulsion system introducing parallel combustors as recited in claim 4 wherein said outer duct (29) further comprises:
a second external communication portion (9), said mixer (700) having a mixer access, a second end of said second external communication portion (9) communicating with said mixer access so that said mixer (700) can communicate with said external duct (101);
a first end of the second external communication portion (9) communicates with a first end of the second combustion chamber (410).
6. The propulsion system of a mixed exhaust turbofan introduced into parallel combustion chambers according to any of claims 1-5 wherein downstream of the first combustion chamber (400) and in the flow direction of the inner duct (28) there are further provided in sequence: a high-pressure turbine (500) and a low-pressure turbine (600);
downstream of the low pressure turbine (600) is the mixer (700).
7. The hybrid exhaust turbofan engine propulsion system incorporating parallel combustion chambers of claim 6 further comprising a tail nozzle (800);
the tail nozzle (800) is communicated with the second end of the mixer (700) through a seventh inner duct connecting part (7) positioned in the flow direction of the inner duct (28).
CN202010485871.2A 2020-06-01 2020-06-01 Mixed exhaust turbofan engine propulsion system introducing parallel combustion chambers Pending CN111779592A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102128101A (en) * 2010-10-19 2011-07-20 靳北彪 Jet engine with parallel combustion chambers
CN105986930A (en) * 2015-03-02 2016-10-05 袁志平 Exhaust mixer of turbofan engine
US20180149115A1 (en) * 2016-11-25 2018-05-31 Rolls-Royce Plc Gas turbine engine
CN208831104U (en) * 2018-07-24 2019-05-07 浙江华擎航空发动机科技有限公司 A kind of gear drive fanjet

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102128101A (en) * 2010-10-19 2011-07-20 靳北彪 Jet engine with parallel combustion chambers
CN105986930A (en) * 2015-03-02 2016-10-05 袁志平 Exhaust mixer of turbofan engine
US20180149115A1 (en) * 2016-11-25 2018-05-31 Rolls-Royce Plc Gas turbine engine
CN208831104U (en) * 2018-07-24 2019-05-07 浙江华擎航空发动机科技有限公司 A kind of gear drive fanjet

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Application publication date: 20201016