CN106801891B - A combined rich and ram gas generator for superb energy systems - Google Patents

Abstract

The invention discloses a fuel-rich and stamping combined gas generator used in a superb energy system. The generator adopts a straight wall section plus sudden expansion and expansion mode for air intake, the first-stage swirl flow is radially air-intake, and the second-stage swirl flow With a 30-degree twist angle axial air intake, the secondary swirler is directly connected to the wall of the flame tube. The combined gas generating device can simultaneously meet the requirements of the total pressure loss of the flow field and the temperature distribution requirements of the outlet of the combustion chamber (greater than 900°C) under the inlet conditions of the two working modes of stamping and self-contained energy. When working in the ram mode, if the inlet flow temperature is higher than 900°C, the gas generator will not inject oil for combustion, and it will only be used as a ram combustion chamber; if the inlet flow temperature is lower than 900°C, the gas generator will A small amount of oil is sprayed for combustion, so that the outlet temperature of the combustion chamber reaches 900°C. When working in self-contained energy mode, the gas generating device works in rich combustion mode, and the combustion chamber is injected with rich fuel oil to control the outlet temperature of the combustion chamber at 900°C to save gas source consumption.

Description

A combined rich and ram gas generator for superb energy systems

technical field

The invention relates to the field of integrated auxiliary power unit (IPU), in particular to a fuel-rich and ram combined gas generator used in a superb energy system. The designed combustion chamber should satisfy the stable, high-efficiency and low-resistance working characteristics of the IPU in all working conditions of auxiliary power supply mode, emergency power supply mode and emergency start mode.

Background technique

The second power system is a multi-functional integrated system, which is a component of the aircraft flight support system. It has the functions of starting the main engine, providing the air source required by the air conditioning system, providing hydraulic energy, providing auxiliary power and emergency power, And make the layout of airborne components such as generators and hydraulic pumps more reasonable. The second power system mainly includes: auxiliary power unit (APU), emergency power unit (EPU) and combined power unit (IPU).

The structural characteristics and cycle process of modern aviation gas turbine engines determine that they must be driven by other power sources before they can work autonomously. Initially, the power source for driving the engine was the electric starter. Later, as the starting power required by the engine increased, the auxiliary power unit (APU) gradually replaced the electric starter and became the main power source for modern starting engines. The second power The system also came into being with the emergence of APU.

For military fighters, especially single-engine aircraft, the second power system usually includes an emergency power unit (EPU) in addition to the APU. If the engine stalls or the generator or hydraulic pump fails during flight, the EPU can provide independent energy to the critical loads of the flight control and electrical systems until the engine restarts, the pilot is ejected safely, or the aircraft stops and lands. The second power system is usually composed of APU, EPU, accessory drive and energy conversion accessories (such as generators, hydraulic pumps), etc. It is mainly used to provide gas, electricity, hydraulic pressure and shaft power to meet the needs of the aircraft for engine starting and emergency energy. Or the different needs of other auxiliary energy sources.

With the increasing advancement and complexity of modern propulsion technology, especially the emergence of turbofan engines with higher bypass ratios and remote-controlled autopilot aircraft, the requirements for the second power of aircraft have greatly increased compared to early aircraft. Variety. The two power requirements of modern aircraft are: either a self-breathing APU with quick start capability at very high altitudes and/or a stored energy supply of jet fuel with single component or bicomponent fuel These demands have led to the emergence of a super integrated power unit (Integrated Power Units, referred to as IPU). This integrated power unit (IPU) can realize that only a simple aircraft power unit can meet Power requirements for all secondary power and main engine starts throughout the flight envelope.

An IPU can replace and provide functions normally operated by three power packs or subsystems, these functions are 1) main engine start; 2) auxiliary power unit (APU) functions; 3) in-flight once power from the main engine is lost Emergency power unit.

1) Start the main engine

There are several ways to start the main engine. On some aircraft (F-15, F-16), a jet fuel starter (which is itself a small turbine engine) is started from stored hydraulic energy; when the jet fuel starter is running , used to drive the propulsion engine, through the gearbox, to the ignition speed. On the other aircraft (B-1), an APU is activated and the propulsion engines are activated through the gearbox. On some aircraft (F-18, A-10, F-22), the main engine is spin-started by an air turbine powered by compressed air from the APU.

2) APU function

If the aircraft has an onboard self-breathing APU power unit, it provides main engine starting and/or ground environmental control and inspection of aircraft electrical and avionics systems without the need for ground power vehicles or other ground equipment.

3) Emergency power

In the event of a main engine stall or generator or hydraulic pump failure in flight, the Emergency Power Unit (EPU) can provide an independent source of power to operate critical flight controls and electrical loads until the engine can be restarted, or the pilot can be ejected safely, or Until you can turn off the fire and make an emergency landing. The F-16 has such a device that provides limited electrical and hydraulic power, working with hydrazine, a propellant stored onboard. The F-16 unit can also work with air drawn in by the main engine, if the main engine is still running.

The IPU needs to provide the functionality of all three powertrain components above with maximum reliability within minimum size and weight constraints, while other technologies should also be maintained on aircraft with more electronic systems.

Contents of the invention

The invention establishes the design scheme of the combined gas generating device of the superb energy system, solves the numerical simulation technology of the oil-rich and high-pressure combustion process, and realizes the performance estimation of the combined gas generating device within the full-envelope working range.

Technical solutions:

A combined fuel-rich and ram-press gas generator for superb energy systems, characterized in that it includes a diffuser section and a combustion chamber; the diffuser section includes a pre-diffuser of a straight wall section and a diffuser burst zone, the outlet of the pre-diffuser is connected to the inlet of the diffuser sudden expansion zone; the outlet of the diffuser sudden expansion zone is connected to the combustion chamber inlet;

A flame cylinder is arranged in the combustion chamber, and a primary cyclone and a secondary cyclone are installed at a certain distance at the entrance of the flame cylinder; the primary cyclone adopts a single-stage radial straight blade cyclone ; The secondary swirler adopts a single-stage axially twisted vane swirler with a twist angle of 30 degrees; a tail nozzle is provided at the outlet of the flame tube.

The sudden expansion gap of the sudden expansion zone of the diffuser is 30 mm, and the sudden expansion zone angle is 60 degrees.

The length of the prediffuser is 78mm, and the inlet diameter is 90mm.

The number of blades of the primary cyclone (3) and the secondary cyclone (4) is between 8 and 12; the number of blades is based on the number of blades of the primary cyclone (3) and the secondary cyclone The comprehensive consideration of the performance and weight of flow device (4) is obtained.

The blades of the primary cyclone are 8 pieces; the outer diameter of the blades is 28.5 mm, the inner diameter is 20.8 mm, the length, height and thickness of the blades are 12 mm, 8 mm, and 1.5 mm respectively, and the installation angle is 60 degrees.

The secondary cyclone has 12 blades, the outer diameter of the blades is 63 mm, the inner diameter is 46 mm, the length, height and thickness of the blades are 18 mm, 15 mm, and 2 mm respectively, and the installation angle is -60 degrees.

The overall outer casing of the combustion chamber has a length of 450mm and a diameter of 184mm.

The diameter of the flame tube is 108 mm, and the length of the flame tube between the trailing edge of the secondary swirler 4 and the tail nozzle 7 is 220 mm.

The tail nozzle has a contraction angle of 45 degrees, a length of 20mm, and a diameter of 62mm.

Beneficial effect:

(1) The gas generating device can meet the working requirements under the intake conditions of the two modes of ram and fuel-rich, and ensure that the total pressure loss of the flow field under the intake conditions of the two modes is less than 14.8% of the total pressure loss of the design point, and the outlet The temperature profile reaches 900°C. Only this one structure can satisfy the two working modes of stamping and fuel-rich, and there is no need to operate the two working modes under different structures.

Description of drawings

Fig. 1 is the overall schematic view of the combustion chamber in the present invention, 1 represents the pre-diffuser, 2 represents the sudden expansion area of the diffuser, 3 represents the primary swirler, 4 represents the secondary swirler, and 5 represents the outer wall surface of the combustion chamber , 6 represents the flame tube, and 7 represents the tail nozzle.

Fig. 2 is a schematic diagram of the flame cylinder in the present invention.

Fig. 3 is a schematic diagram of a diffuser in the present invention.

Fig. 4 is a schematic diagram of the primary cyclone in the present invention.

Fig. 5 is a schematic diagram of the secondary cyclone in the present invention.

Fig. 6 is the total pressure distribution of the outlet section under different working conditions in the stamping mode under the optimized scheme in the present invention, 1 indicates Case5, 2 indicates Case4, 3 indicates Case3, 4 indicates Case2, and 5 indicates Case1;

Figure 7 shows the total pressure loss under different working conditions in the stamping mode of the optimized scheme.

Fig. 8 Temperature distribution diagram of outlet section under different working conditions of stamping mode, 1 indicates Case1, 2 indicates Case5, 3 indicates Case4, 4 indicates Case2, 5 indicates Case3;

Fig. 9 Velocity contour map in stamping mode;

Figure 10 Temperature contour map in stamping mode

Figure 11 Speed contour map in self-contained energy mode

Figure 12 Temperature contour map in self-contained energy mode;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

The present invention provides a fuel-rich and ram-combined gas generator for super energy systems. In order to make the purpose, technical solutions and effects of the present invention clearer and clearer, the present invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific implementations described here are only used to explain the present invention, not to limit the present invention.

The stamping and combined gas generating device of the superb energy system of the present invention is a key component of the integrated auxiliary power unit (IPU), and the combustion chamber must meet all working conditions of the IPU in the auxiliary power supply mode, emergency power supply mode and emergency start mode Stable and efficient low-resistance working characteristics.

Fig. 1 is the overall schematic diagram of the combustion chamber in the present invention. As shown in Figure 1, a fuel-rich and ram combined gas generator for advanced energy systems provided by the present invention includes a combustion outer wall surface 5, a diffuser section, a flame tube 6, a primary swirler 3, a secondary Swirler 4 and tail nozzle 7.

The overall outer casing of the combustion chamber has a length of 450mm and a diameter of 184mm. The diameter of the flame tube 6 is 108 mm, the length of the flame tube between the rear edge of the secondary cyclone 4 and the tail nozzle 7 is 220 mm, the contraction angle of the tail nozzle 7 is 45 degrees, the length is 20 mm, and the diameter is 62 mm. The tail nozzle 7 is installed at the end outlet of the flame tube 6 . The longer length of the flame tube can prevent the recirculation zone from being too close to the outlet, and the larger diameter of the flame tube and the combustion chamber can also reduce the resistance loss of the combustion chamber.

The diffuser section adopts the method of straight wall section plus sudden expansion to realize the expansion of the inlet airflow. The diffuser section includes the prediffuser 1 and the diffuser sudden expansion area 2. The outlet of the prediffuser 1 and the diffuser The inlet of the sudden expansion zone 2 of the compressor is connected; the length of the pre-diffuser 1 is 78mm, the diameter of the inlet is 90mm, the sudden expansion gap of the diffuser sudden expansion zone 2 is 30mm (without a cap), the angle of the sudden expansion zone is 60 degrees, straight The method of adding sudden expansion to the wall section solves the problem of flow separation in the diffuser. The outlet of the diffuser sudden expansion area 2 is connected with the inlet of the combustion chamber.

The air intake adopts the air intake type of the primary and secondary swirlers. The first-stage cyclone 3 adopts 8 pieces of single-stage radial straight blade cyclone, the outer diameter is 28.5mm, the inner diameter is 20.8mm, the length, height and thickness of the blades are 12mm, 8mm, and 1.5mm respectively, and the installation angle is 60 degrees, that is, it is clamped with the circumference Install at an angle of 60 degrees. The secondary swirler 4 adopts 12 single-stage axially twisted vane swirlers with a twist angle of 30 degrees, so that the airflow generates a radial partial velocity after passing through the secondary swirler 4 . The outer diameter of the secondary cyclone 4 is 63mm, the inner diameter is 46mm, the length, height and thickness of the blades are 18mm, 15mm, and 2mm respectively, and the installation angle is -60 degrees. The primary cyclone 3 and the secondary cyclone 4 are connected by a cylinder with a length of 42mm, that is, the axial distance between the tail end of the primary cyclone 3 and the tail end of the secondary cyclone 4 is 42mm . The larger flow area of the cyclone is beneficial to reduce the total pressure loss. In the present invention, the number of blades of the primary cyclone 3 and the secondary cyclone 4 is between 8 and 12, and the number of blades is based on the performance and weight of the primary cyclone 3 and the secondary cyclone 4 obtained by comprehensive compromise consideration.

The air flows in from the pre-diffuser 1, and after passing through the sudden expansion area 2 of the diffuser, the air flows from the primary swirler 3 and the secondary swirler 4 into the flame tube 6, burns in the flame tube 6, and finally passes through the Tail nozzle 7 discharges exhaust gas. The diffuser section is used to reduce the inlet velocity, and after passing through the primary and secondary cyclones, airflows with different rotation directions are generated to form a low-speed recirculation zone. The different size and structural design of the diffuser section and the two-stage cyclone meet the flow requirements of the stamping and self-contained energy modes and the outlet temperature distribution requirements after ignition.

The inlet conditions in the ram mode and the rich mode are different, but the requirements of the total pressure loss and the outlet temperature distribution of the combustion chamber must be met when working in both modes. The combined gas generating device can meet the requirement that the total pressure loss is less than the design point under the conditions of ram pressure and fuel-rich inlet. Regarding the outlet temperature distribution of the combustion chamber, when working in the ram mode, when the inlet flow temperature is higher than 900°C, the gas generating device does not inject oil for combustion, and is only used as a ram combustion chamber. When the inlet flow temperature is low At 900°C, the gas generating device sprays a small amount of oil for combustion, so that the outlet temperature of the combustion chamber reaches 900°C. When working in self-contained energy mode, this mode is mainly used for starting and emergency working conditions. At this time, it is necessary to save air compression. At this time, the gas generator works in rich combustion mode, and the combustion chamber injects too rich fuel to control The outlet temperature of the combustion chamber is 900°C to save gas source consumption. Regardless of the ram mode or the rich mode, the outlet temperature of the combustion chamber can reach 900°C under the respective inlet conditions through a certain amount of fuel supply.

In order to study the flow characteristics of the combined gas generator in the present invention, a numerical simulation has been carried out on the flow under different working conditions of the stamping mode, as shown in Figure 6, the outlet total pressure distribution under different stamping states under the optimized scheme, as can be seen from the figure The total pressure to the center of the outlet is smaller than that on both sides. From the total pressure loss in Figure 7, the total pressure loss is within 20% under different working conditions, which meets the low-resistance flow conditions.

It can be seen from Fig. 8 that the temperature distribution of the outlet section under each stamping condition is the highest near the center and the lowest near the wall. This temperature distribution meets the structural reliability requirements of the combustion chamber and the subsequent turbine. With the change of different working conditions, the temperature distribution in the combustion chamber and the outlet temperature distribution have similar laws, but the values are different. The flow field structure of the combustion chamber and the fuel injection scheme determine the fuel distribution in the combustion chamber, and also determine the temperature distribution in the combustion chamber and the outlet temperature distribution. From the point of view of the outlet temperature, the condition that the outlet temperature of the combustion chamber reaches 900°C is met.

Fig. 9 and Fig. 10 are velocity contour diagrams and temperature contour diagrams simulated in stamping mode. Due to the existence of the upper and lower convection zones downstream of the outlet of the head primary cyclone, favorable conditions are provided for flame stability. The high-temperature zone is mainly located in the reflux zone, where the concentration is high and the chemical reaction rate is high, so the heat generated by the chemical reaction is large. After that, the temperature decreases, but the temperature distribution along the cross-sectional direction tends to be uniform until the outlet cross-section temperature is the lowest.

Fig. 11 and Fig. 12 are the speed contour diagrams and temperature contour diagrams simulated in self-contained energy mode. In the self-contained mode, it is in a fuel-rich combustion state, and there are two stages of fuel supply. The combustion heat release generated by the primary fuel supply mainly provides enough energy for the recirculation zone to meet the energy requirements for the evaporation and ignition of the fuel oil supplied by the second stage, while the secondary fuel supply mainly meets the energy requirements of the fuel oil after the recirculation zone. The chemical reaction makes the entire combustion chamber in a relatively uniform oil-rich combustion state and increases the outlet temperature of the combustion chamber.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A fuel-rich and ram combined gas generator for superb energy systems, characterized in that: it includes a diffuser section and a combustion chamber; the diffuser section includes a pre-diffuser (1) of a straight wall section and The diffuser sudden expansion area (2), the outlet of the pre-diffuser (1) is connected with the inlet of the diffuser sudden expansion area (2); the diffuser sudden expansion area (2) The outlet is connected to the inlet of the combustion chamber; A flame cylinder (6) is arranged in the combustion chamber, and a primary cyclone (3) and a secondary cyclone (4) are installed at a certain distance at the entrance of the flame cylinder (6); The swirler (3) adopts a single-stage radial straight blade swirler; the secondary swirler (4) adopts a single-stage axially twisted blade swirler with a twist angle of 30 degrees; in the flame tube ( 6) The outlet is provided with a tail nozzle (7). 2. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the sudden expansion gap of the diffuser sudden expansion area (2) is 30 mm, and the sudden expansion area angle is 60 degrees. 3. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the length of the pre-diffuser (1) is 78mm, and the inlet diameter is 90mm. 4. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the number of blades of the primary swirler (3) and the secondary swirler (4) is between 8 and 12 pieces The number of blades is obtained based on the comprehensive consideration of the performance and weight of the primary cyclone (3) and secondary cyclone (4). 5. The fuel-rich and ram combined gas generator according to claim 4, characterized in that: the blades of the primary cyclone (3) are 8 pieces; the outer diameter of the blades is 28.5mm, and the inner diameter is 20.8mm, The length, height and thickness of the blades are 12mm, 8mm, and 1.5mm respectively, and the installation angle is 60 degrees. 6. The fuel-rich and stamping combination gas generator according to claim 4, characterized in that: the blades of the secondary swirler (4) are 12 pieces, the outer diameter of the blades is 63mm, the inner diameter is 46mm, and the length of the blades is The height and thickness are 18mm, 15mm, and 2mm respectively, and the installation angle is -60 degrees. 7. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the overall outer casing of the combustion chamber has a length of 450mm and a diameter of 184mm. 8. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the diameter of the flame tube (6) is 108 mm, and the trailing edge of the secondary swirler (4) to the tail nozzle (7) The length of the flame tube between them is 220mm. 9. The fuel-rich and ram combined gas generator according to claim 1, characterized in that: the tail nozzle (7) has a contraction angle of 45 degrees, a length of 20 mm, and a diameter of 62 mm.