Evaporation centrifugal grading combustion chamber of microminiature turbine engine

Abstract

Structurally, a centrifugal nozzle is arranged on the wall surface of the head of a flame tube and is matched with a tangential air inlet hole or a tangential air inlet groove of the head to form an on-duty combustion area; the evaporation pipe is arranged on the outer barrel wall face of the flame barrel, a radial inlet is adopted, and a direct injection type oil supply spray needle is arranged in the evaporation pipe and used for forming a main combustion stage combustion area. According to the working principle, the centrifugal nozzle continuously supplies oil through the auxiliary oil way, is responsible for starting and efficient combustion in a small state, and serves as an ignition source of the main combustion stage in a large state; the direct injection type oil supply spray needle supplies oil only in a large state through the main oil way, and fuel oil is sprayed out for combustion after being atomized and evaporated in the evaporation pipe. The centrifugal nozzle and the evaporation pipe are arranged in a non-coaxial mode, the problems of wall face ablation and nozzle blocking are solved, reliability is improved, and the service life is prolonged; through the compact design that graded oil supply is matched with the radial evaporation pipe, on the premise that it is guaranteed that the combustion chamber is small in size and low in cost, the starting and working envelope of an engine is greatly widened, and thrust is improved.

Description

Technical Field

[0001] This invention relates to the field of engine technology, specifically to a micro-turbine engine evaporative centrifugal staged combustion chamber. Background Technology

[0002] In the modern battlefield environment, air defense systems are becoming increasingly sophisticated, and various detection networks are becoming more dense. High-intensity reconnaissance and counter-reconnaissance have become the norm, posing a severe challenge to the survivability and strike capabilities of micro-sized aircraft. Unmanned aerial vehicles (UAVs) powered by micro-sized turbine engines possess excellent altitude and speed characteristics, good terminal penetration capabilities, low high-frequency noise, and outstanding stealth performance. Moreover, their cost is far lower than that of large and medium-sized aircraft, enabling them to form large-scale long-range reconnaissance and rapid strike capabilities, thus becoming a core technological support for implementing strategic-level precision warfare.

[0003] The increasing use of miniature turbocharged engines and the diversification of their operating scenarios have placed demands on the combustion chambers of these engines, requiring simple structure, low cost, and high efficiency with a wide combustion envelope. Currently, miniature turbocharged engines mostly employ evaporator tube combustion chambers and direct-injection needle fuel injectors. Evaporator tube combustion chambers are simple in structure and low in cost, and exhibit good combustion performance under general conditions with high inlet temperature and pressure. However, under starting conditions and low-pressure conditions with low inlet temperature and pressure, the low evaporation rate leads to poor ignition performance, unstable combustion, and low combustion efficiency, affecting the engine's operating envelope and thrust.

[0004] To solve this problem, a simple single-oil-circuit centrifugal nozzle is usually used for auxiliary fuel supply. However, in the existing evaporator combustion chamber design, the centrifugal nozzle is usually arranged coaxially with the evaporator, and the space at the head of the combustion chamber is squeezed by the evaporator, resulting in poor flame stabilization effect of the centrifugal nozzle. When the centrifugal nozzle and the evaporator work together, the oil mist cone downstream of the centrifugal nozzle directly contacts the wall of the evaporator, which can easily cause wall erosion.

[0005] Due to the above issues, the centrifugal nozzle can only be used when the combustion chamber is ignited and cannot supply fuel simultaneously with the evaporator pipe, thus failing to improve combustion performance under stable combustion conditions. Furthermore, since the centrifugal starter nozzle does not supply fuel when the evaporator pipe is working, it is prone to nozzle blockage due to carbon buildup and coking, causing the engine to fail to start multiple times. Summary of the Invention

[0006] The purpose of this invention is to provide a compact, low-cost micro-turbine engine with an evaporative centrifugal staged combustion chamber that exhibits good combustion performance in start-up, low-pressure, and high-pressure conditions. In start-up and low-pressure conditions, it relies on the excellent atomization combustion performance of the centrifugal nozzle, while in high-pressure conditions, it relies on the excellent atomization combustion performance of the evaporator and direct-injection fuel needle. Thus, while ensuring small engine size, compact structure, and low manufacturing cost, it significantly broadens the overall engine start-up and operating envelope and increases engine thrust.

[0007] To achieve the above objectives, the present invention proposes the following technical solution: a micro-turbine engine evaporative centrifugal staged combustion chamber, comprising a flame tube, at least one centrifugal nozzle and at least one evaporation tube, wherein the centrifugal nozzle and the evaporation tube are independent structures and are respectively disposed on the wall surface of the flame tube; The flame tube includes an outer flame tube, a flame tube head, and an inner flame tube, with flame tube wall inlet holes provided on the walls of the outer and inner flame tubes.

[0008] Furthermore, in this invention, the centrifugal nozzle is disposed on the wall surface of the flame tube head, and the oil spraying direction is axial; The flame tube head wall is provided with a tangential air inlet hole or tangential air inlet groove, which is used to make the airflow entering the flame tube head form a rotating flow around the centrifugal nozzle.

[0009] Furthermore, in this invention, the evaporation tube is disposed on the wall surface of the outer cylinder of the flame tube; The evaporator tube consists of an evaporator tube inlet section and an evaporator tube outlet section. The evaporator tube inlet section is arranged radially, and the plane of the evaporator tube outlet section is perpendicular to the evaporator tube inlet section.

[0010] Furthermore, in this invention, the centrifugal nozzles are arranged alternately with the evaporation tubes in the circumferential direction; The total number of centrifugal nozzles in the circumferential direction is less than or equal to the total number of evaporator tubes in the circumferential direction.

[0011] Furthermore, in this invention, an auxiliary oil supply ring is also included, through which the centrifugal nozzle is independently supplied with oil; The fuel supplied by the centrifugal nozzle mixes with the air intake through the tangential air intake hole or tangential air intake groove at the head of the flame tube to form the duty combustion zone.

[0012] Furthermore, in this invention, the centrifugal nozzle continuously supplies fuel during the operation of the combustion chamber.

[0013] Furthermore, this invention also includes a main oil supply ring and a direct-injection oil supply needle; The direct-injection oil supply needle extends radially into the inlet section of the evaporator tube and is independently supplied with oil through the main oil circuit oil supply ring; The fuel supplied by the direct-injection fuel needle forms the main combustion zone downstream of the evaporator.

[0014] Furthermore, in this invention, the direct-fired fuel injection needle supplies fuel only when the combustion chamber is in a high-pressure state, and does not supply fuel during combustion chamber startup and low-pressure state.

[0015] Furthermore, in this invention, during startup and low-pressure operation, only the centrifugal nozzle supplies oil through the auxiliary oil supply ring; Under normal operating conditions, the centrifugal nozzle supplies oil through the auxiliary oil supply ring, and the direct-injection oil supply needle supplies oil through the main oil supply ring.

[0016] Furthermore, the present invention also includes a combustion chamber casing, a diffuser bushing, and a turbine guide; The combustion chamber casing is located outside the flame tube; The diffuser bushing is located at the front end and inside of the flame tube; The turbine guide is installed at the combustion chamber outlet behind the flame tube.

[0017] Beneficial effects: The technical solution of this application has the following technical effects: 1. The radial evaporator tube layout is adopted, with the inlet section of the evaporator tube being radial. Compared with the traditional axial layout of front / rear evaporator tubes, it occupies less head space, making the overall structure of the combustion chamber compact and small in size. The oil-gas mixture in the evaporator tube flows out and forms a jet, which can be quickly ignited by the duty flame, improving the flame transmission speed and flame stability during large-scale combustion.

[0018] 2. A staged and zoned flame stabilization design combining tangential orifices, centrifugal nozzles, and radial evaporator tubes is adopted to improve combustion chamber performance under various operating conditions. During startup and low-pressure combustion, the rotating flow of the tangential orifices and the centrifugal nozzles maintain good atomization and flame stabilization capabilities, thereby achieving excellent ignition and shutdown performance and broadening the engine's starting envelope. Under high-pressure combustion, the radial evaporator tubes significantly enhance evaporation mixing capabilities, thereby achieving excellent combustion efficiency and increasing engine thrust.

[0019] 3. The centrifugal nozzle + radial evaporator tube non-axial layout design, compared with the traditional coaxial layout, the combustion zone and the evaporator tube wall are far apart, the flame will not cause erosion of the evaporator tube wall, and the centrifugal nozzle can supply fuel in all working states, effectively preventing blockage, thereby greatly improving the reliability and life of the combustion chamber, and providing multiple start-up capability.

[0020] 4. Different levels of oil supply design for different states: in low state, only centrifugal nozzle is used for oil supply, while in high state, a combination of evaporator pipe and centrifugal nozzle is used for oil supply. The oil supply pressure is low and no high-pressure oil pump is required, which greatly reduces the cost and weight of the oil supply system.

[0021] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0022] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0023] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of the cross-sectional structure of the centrifugal nozzle in the evaporative centrifugal staged combustion chamber of a micro-turbine engine; Figure 2 A schematic diagram of the cross-sectional structure of the evaporator tube in the evaporative centrifugal staged combustion chamber of a micro-turbine engine; Figure 3 A schematic diagram of a micro-turbine engine's evaporative centrifugal staged combustion chamber without an outer casing and diffuser bushing. Figure 4 Rear view of the head structure of the evaporative centrifugal staged combustion chamber in a micro-turbine engine; Figure 5 A partial structural diagram of the evaporator pipe and direct-injection fuel injection needle; In the figure, the meanings of the various reference numerals are as follows: 1. Combustion chamber inlet; 2. Combustion chamber casing; 3. Diffuser bushing; 4. Flame tube; 5. Auxiliary fuel supply ring; 6. Centrifugal nozzle; 7. Tangential air inlet or tangential air inlet groove at the head of the flame tube; 8. Main fuel supply ring; 9. Direct injection needle; 10. Evaporator pipe; 11. Air inlet on the flame tube wall; 12. Combustion chamber outlet; 13. Turbine guide vane; 41. Outer cylinder of the flame tube; 42. Flame tube head; 43. Inner cylinder of the flame tube. Detailed Implementation

[0024] The embodiments of the invention are described in detail below with reference to the accompanying drawings to clearly illustrate the structure, purpose, advantages, positional relationship, and connection method of each component. It should be noted that the directional indications (such as "front," "back," "up," and "down") involved in this embodiment are based on the posture shown in the accompanying drawings and are only used to describe the relative positional relationship and movement of the components; if the posture changes, the directional indications will be adjusted accordingly. The term "connection" includes mechanical connections and electrical connections; it can be a fixed connection, a detachable connection, or an indirect connection through an intermediate medium; the specific meaning is understood by those skilled in the art based on the context.

[0025] like Figure 1-5As shown; this embodiment provides a micro-turbine engine evaporative centrifugal staged combustion chamber, as attached. Figure 1 To be continued Figure 5 As shown, its main structure includes: combustion chamber inlet 1, combustion chamber casing 2, diffuser bushing 3, flame tube 4, auxiliary oil supply ring 5, centrifugal nozzle 6, tangential air inlet or tangential air inlet groove at the head of the flame tube 7, main oil supply ring 8, direct injection needle 9, evaporator pipe 10, air inlet on the wall of the flame tube 11, combustion chamber outlet 12, and turbine guide 13.

[0026] In terms of overall layout, the combustion chamber casing 2 and the diffuser sleeve 3 together form the outer boundary of the combustion chamber, which is used to house internal components such as the flame tube 4, and to constrain and guide the incoming air flow entering from the combustion chamber inlet 1. The flame tube 4 is located in the center of the combustion chamber and is the core area of ​​combustion. It includes an outer flame tube 41, a flame tube head 42, and an inner flame tube 43. Both the outer flame tube 41 and the inner flame tube 43 have flame tube wall air inlets 11, which are used to introduce air for cooling the flame tube wall, afterburning in the later stages of combustion, and regulating the temperature distribution at the combustion chamber outlet 12.

[0027] The core of this invention lies in the use of a multi-stage, non-axial layout for the centrifugal nozzles and evaporation tubes. Specifically, as shown in the attached diagram... Figure 1 and attached Figure 4 As shown, the centrifugal nozzle 6, acting as a standby nozzle, is installed on the wall of the flame tube head 42, with its injection direction along the combustion chamber axis. The centrifugal nozzle 6 receives independent fuel supply through the auxiliary fuel supply ring 5. To cooperate with the operation of the centrifugal nozzle 6, a tangential air inlet or tangential air inlet groove 7 is also provided on the wall of the flame tube head 42. The purpose of this structure is to ensure that the air entering the flame tube head 42 has a certain tangential flow component, thereby forming a stable and strong head rotation flow 16 around the centrifugal nozzle 6. This rotation flow has a strong flame stabilization capability, effectively entraining and atomizing the fuel injected by the centrifugal nozzle 6, forming a stable standby combustion zone 14. Its advantage is that the centrifugal nozzle 6 relies on its own pressure for atomization, combined with the flame stabilization effect of the rotation flow 16, to achieve reliable ignition and efficient and stable combustion even under engine starting or low-pressure conditions (low inlet air temperature and pressure).

[0028] As attached Figure 2 and attached Figure 5As shown, the evaporator tube 10, as the main combustion stage, is independently installed on the wall of the outer cylinder 41 of the flame tube and arranged radially. The advantage of this radial layout is that the evaporator tube 10 does not occupy the valuable space of the flame tube head 42, making the overall structure of the combustion chamber more compact. At the same time, it also provides ample space for the head rotation flow 16, enhancing the flame stabilization effect of the shift 14. The evaporator tube 10 is preferably T-shaped or Г-shaped, consisting of a radial evaporator tube inlet section 101 and an evaporator tube outlet section 102 perpendicular to the inlet section. Each evaporator tube 10 is equipped with a direct-injection fuel injection needle 9, which extends radially into the evaporator tube inlet section 101 and obtains independent fuel supply through the main fuel supply ring 8.

[0029] The working principle of this embodiment is explained as follows: During engine start-up and low-speed / high-altitude conditions, the incoming air temperature and pressure at combustion chamber inlet 1 are relatively low. At this time, only the auxiliary fuel supply ring 5 supplies fuel to the centrifugal nozzle 6. After being atomized by the centrifugal nozzle 6, the fuel mixes with air entering through the tangential intake port or tangential intake groove 7 at the head of the flame tube. This head-rotating airflow 16 effectively prolongs the fuel residence time and enhances fuel-air mixing, forming a stable shift combustion zone 14. During this time, the main fuel supply ring 8 does not supply fuel. This design solves the defects of traditional evaporator tube combustion chambers, such as low evaporation rate, difficulty in ignition, and unstable combustion under low-speed conditions.

[0030] When the engine operates under high-altitude, high-speed, and other demanding conditions, the incoming air temperature and pressure at the combustion chamber inlet 1 are relatively high. At this time, the auxiliary fuel supply ring 5 continues to supply fuel to the centrifugal nozzle 6, maintaining stable combustion in the standby combustion zone 14. Simultaneously, the main fuel supply ring 8 begins supplying fuel to the direct-injection fuel needle 9. Fuel is injected into the evaporator inlet section 101, where it encounters the high-temperature, high-pressure air (i.e., strong aerodynamic atomization) entering the evaporator tube 10. It rapidly atomizes, evaporates, and mixes thoroughly within the tube, forming a homogeneous fuel-air mixture. This fuel-air mixture is then injected at high speed into the flame tube 4 through the evaporator outlet section 102. Since the standby combustion zone 14 is currently burning stably, it immediately acts as an ignition source, rapidly igniting the fuel-air mixture ejected from the evaporator tube 10, forming the main combustion zone 15 with higher combustion intensity and greater heat release.

[0031] The beneficial effects of this embodiment are significant. First, the non-axial layout of the centrifugal nozzle 6 and the evaporator tube 10 ensures that the flame in the combustion zone 14 is far from the wall of the evaporator tube 10, completely avoiding the problem of flame erosion of the evaporator tube wall in traditional coaxial designs. Second, the centrifugal nozzle 6 continuously supplies fuel under all engine operating conditions (including the most demanding conditions), effectively preventing carbon buildup or coking of fuel in the nozzle, avoiding nozzle clogging, ensuring reliable multiple start-up capability of the engine, and significantly improving the operational reliability and lifespan of the combustion chamber. Finally, the staged fuel supply system requires only low-pressure fuel supply at each stage, eliminating the need for expensive and bulky high-pressure fuel pumps, significantly reducing engine manufacturing costs and system weight.

[0032] Existing evaporator tube combustion chamber designs typically employ a coaxial layout of axial evaporator tubes and axial centrifugal nozzles, with the evaporator tubes positioned at the center of the flame tube head and the centrifugal nozzles on one side. This invention utilizes a non-axial layout for the evaporator tubes and centrifugal nozzles, transforming the evaporator tubes from an axial to a radial arrangement, and incorporating tangential air inlets or grooves at the combustion chamber head. This layout creates a standby combustion zone supplied by the centrifugal nozzles and a main combustion zone supplied by the evaporator tubes within the flame tube. This staged and zoned combustion organization significantly expands the space of the standby combustion zone, while the tangential air inlet structure at the head creates a rotating flow, enhancing the flame stabilization performance of the combustion chamber. This structure also keeps the evaporator tube wall away from the standby flame, with the evaporator tube outlet jet directly facing the standby flame, thus resolving the conflict between rapid flame propagation and preventing evaporator tube wall erosion. This allows the centrifugal nozzles to operate continuously under all conditions, improving flame propagation speed and combustion chamber lifespan. The structure proposed in this invention fundamentally changes the existing structural design, fuel supply design, and combustion organization of evaporator tube combustion chambers. Its technical principles and implementation are significantly different from existing technologies. Compared with other graded combustion chamber design ideas such as cyclone staged zoning, flame stabilizer staged zoning, and concave cavity staged zoning, the graded combustion organization of centrifugal nozzle + evaporator tube proposed in this invention has outstanding features such as simple structure, low cost, and small space occupation. It is the only graded combustion organization method suitable for evaporator tube combustion chambers of micro-small engines.

[0033] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A micro-turbine engine evaporative centrifugal staged combustion chamber, characterized in that: It includes a flame tube (4), at least one centrifugal nozzle (6) and at least one evaporation tube (10), wherein the centrifugal nozzle (6) and the evaporation tube (10) are independent structures and are respectively disposed on the wall surface of the flame tube (4); The flame tube (4) includes an outer cylinder (41), a head (42), and an inner cylinder (43). The outer cylinder (41) and the inner cylinder (43) are provided with flame tube wall air inlets (11).

2. The combustion chamber according to claim 1, characterized in that: The centrifugal nozzle (6) is disposed on the wall surface of the flame tube head (42), and the oil spraying direction is axial; The flame tube head (42) has a tangential air inlet or a tangential air inlet groove (7) on its wall surface, which is used to make the airflow entering the flame tube head (42) form a rotating flow around the centrifugal nozzle (6).

3. The combustion chamber according to claim 1, characterized in that: The evaporation tube (10) is disposed on the wall surface of the outer cylinder (41) of the flame tube; The evaporator tube (10) consists of an evaporator tube inlet section (101) and an evaporator tube outlet section (102). The evaporator tube inlet section (101) is arranged radially, and the plane of the evaporator tube outlet section (102) is perpendicular to the evaporator tube inlet section (101).

4. The combustion chamber according to any one of claims 1-3, characterized in that: The centrifugal nozzles (6) are arranged alternately with the evaporation tubes (10) in the circumferential direction; The total number of centrifugal nozzles (6) in the circumferential direction is less than or equal to the total number of evaporation tubes (10) in the circumferential direction.

5. The combustion chamber according to any one of claims 1-4, characterized in that: It also includes an auxiliary oil supply ring (5), through which the centrifugal nozzle (6) is supplied with oil independently; The fuel supplied by the centrifugal nozzle (6) mixes with the air intake through the tangential air intake hole or tangential air intake groove (7) at the head of the flame tube to form the duty combustion zone (14).

6. The combustion chamber according to claim 5, characterized in that: The centrifugal nozzle (6) continuously supplies fuel during the operation of the combustion chamber.

7. The combustion chamber according to claim 3, characterized in that: It also includes the main oil supply ring (8) and the direct injection needle (9); The direct-fired oil injection needle (9) extends radially into the inlet section (101) of the evaporator tube and is independently supplied with oil through the main oil circuit oil supply ring (8); The fuel supplied by the direct-injection fuel needle (9) forms the main combustion zone (15) downstream of the evaporator pipe (10).

8. The combustion chamber according to claim 7, characterized in that: The direct-fired fuel injection needle (9) supplies fuel only when the combustion chamber is in a high-pressure state, and does not supply fuel when the combustion chamber is starting up or in a low-pressure state.

9. The combustion chamber according to claim 8, characterized in that: During startup and low-temperature operation, only the centrifugal nozzle (6) supplies oil through the auxiliary oil supply ring (5); Under normal operating conditions, the centrifugal nozzle (6) supplies oil through the auxiliary oil supply ring (5), and the direct-injection oil supply needle (9) supplies oil through the main oil supply ring (8).

10. The combustion chamber according to any one of claims 1-9, characterized in that: It also includes a combustion chamber casing (2), a diffuser bushing (3), and a turbine guide (13); The combustion chamber casing (2) is located outside the flame tube (4); The diffuser bushing (3) is located at the front end and inside of the flame tube (4); The turbine guide (13) is installed at the combustion chamber outlet (12) behind the flame tube (4).

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