CN113309633B - An engine with a combined layout of variable cycle and continuously variable drive fans - Google Patents

Abstract

The invention discloses an engine with a combined layout of a variable cycle and a stepless variable speed drive fan. The fan is connected to the inner core engine through the use of a stepless speed changer, and the tail nozzle is set as an adjustable tail nozzle with adjustable nozzle area. The nozzle and the continuously variable transmission are used to independently adjust the speed of the fan, so that the speed of the fan is separated from the speed of the inner core machine, so that the inner core machine can operate independently in the highest efficiency state, and the speed of the fan can be continuously changed through the continuously variable transmission. The continuous adjustable nozzle area of the adjustable tail nozzle realizes the continuous adjustment of the engine thrust to adapt to different working conditions of the aircraft. It has both high efficiency and low fuel consumption under the power requirements of multiple working conditions of the unmanned aircraft. Features, and can ensure the stable operation of the engine in subsonic and supersonic conditions.

Description

An engine with a combined layout of variable cycle and continuously variable drive fans

technical field

The invention belongs to the technical field of light-duty power gas turbine engines, and relates to a light-duty power engine, in particular to a light-duty power gas turbine engine with a combined layout of variable-cycle and continuously variable-speed drive fans, which can meet the power requirements of unmanned aerial vehicles in multiple operating conditions. It has the characteristics of high efficiency and low fuel consumption.

Background technique

With the expansion of the operating range of unmanned aerial vehicles from high subsonic speed to supersonic speed, it is required that the thrust, fuel consumption rate, size, etc. of the engine design process can match the requirements of multiple operating conditions within the flight envelope. The engines equipped with unmanned aerial vehicles are usually turbojet engines or turbofan engines. The former has a high fuel consumption rate, but can provide a higher flight speed for the aircraft, while the latter has higher efficiency and higher speed at relatively lower speeds. Low fuel consumption. Under multiple operating conditions such as high-speed cruise and low-speed reconnaissance of unmanned aerial vehicles, the requirements for the engine are conflicting, and it is difficult for a single turbojet engine or turbofan engine to meet the thrust requirements of multiple operating conditions and take into account high efficiency and low consumption. oil rate.

SUMMARY OF THE INVENTION

According to the above problems, combined with the characteristics of the power demand of the unmanned aerial vehicle under multiple operating conditions, for the light-duty power gas turbine engine, the present invention proposes a variable-cycle and continuously variable-speed drive fan combined layout engine. The connotation core machine is connected by transmission, and by setting the tail nozzle as an adjustable tail nozzle with adjustable nozzle area, the continuously variable transmission is used to independently adjust the speed of the fan, so that the speed of the fan is separated from the speed of the connotation core machine, so that the The core engine of the connotation runs independently at the highest efficiency state, continuously changes the speed of the fan through the continuously variable transmission, and cooperates with the continuously adjustable nozzle area of the adjustable tail nozzle to realize the continuous adjustment of the engine thrust to adapt to the different working conditions of the aircraft. It has the characteristics of high efficiency and low fuel consumption under the power requirements of multi-working conditions of unmanned aerial vehicles, and can ensure the stable operation of the engine in subsonic and supersonic conditions.

The present invention is to solve its technical problem, and the technical scheme adopted is:

An engine with a variable cycle and a continuously variable speed drive fan combined layout, including an inner core engine, a fan, two inner and outer ducts, and a tail nozzle, the inner core engine includes a compressor, a combustion chamber and a turbine, the turbine It is connected with the compressor through a transmission shaft. The upstream of the compressor is provided with a fan, and the downstream of the turbine is provided with a tail nozzle. The air enters the tail nozzle through the inner and outer ducts. is,

The fan is drive-connected with the drive shaft of the inner core machine through a continuously variable transmission,

The tail nozzle is an adjustable tail nozzle with an adjustable nozzle area,

The continuously variable transmission is used to independently adjust the rotational speed of the fan, so that the rotational speed of the fan is separated from the rotational speed of the internal core machine, so that the internal core machine can operate independently in the highest efficiency state, and the continuous By changing the rotational speed of the fan, in conjunction with the continuously adjustable nozzle area of the adjustable tail nozzle, the continuous adjustment of the thrust of the engine is realized to adapt to different working conditions of the aircraft.

Another object of the present invention is to provide an aircraft, characterized in that the unmanned aircraft includes the above-mentioned engine of the present invention.

Another object of the present invention is to provide a design method for the above engine, characterized in that the design method at least includes the following steps:

SS1. Input flight conditions, engine data and component characteristics;

SS2. Use the engine speed and the β line as the coordinates to interpolate the various parts of the engine (fan, compressor, turbine) to obtain a characteristic map that meets the flight requirements;

SS3. Select the inner speed and transmission ratio;

SS4. Select the fan β line as the outer iteration loop parameter, the β line is the working envelope (linear or parabolic line between the blockage line and the surge line, there is a certain distance between each β line, which has no physical meaning in itself , but its addition introduces an alternative coordinate system, which can help quickly locate the only working point during design, and is a commonly used tool in design;

SS5. Obtain the fan characteristic map and extract the mass flow, pressure ratio and efficiency;

SS6. Calculate the connotation characteristics;

SS7. Read compressor characteristics;

SS8. Select the total inlet temperature before the turbine as the inner loop iteration parameter;

SS9. Calculate combustion chamber characteristics;

SS10. Calculate turbine characteristics;

SS11. Iterate the connotation cycle to ensure the conservation of connotative quality;

SS12. Iterate the import and export cycle to ensure the conservation of import and export quality.

Compared with the prior art, the variable-cycle and continuously-variable-variable-variable-drive fan layout for light-duty power gas turbine engines provided by the present invention has the following characteristics: 1) High efficiency: the connotation core engine operates independently in the optimal efficiency state, and the engine There is basically no loss of efficiency in the process of thrust change. 2) The thrust can be continuously adjusted: by adjusting the transmission ratio of the continuously variable transmission and the nozzle area, the continuous adjustment of the engine thrust can be realized. 3) Low fuel consumption: thrust is provided by connotation and connotation, which avoids the disadvantage of high fuel consumption in turbojet engines. 4) The structure is relatively simple: Compared with the gear-driven fan, the continuously variable-speed drive fan has a simpler structure, high reliability and strong flexibility. After model verification, the light-duty power gas turbine engine with the combined layout of variable cycle and continuously variable drive fans proposed by the present invention can reduce fuel consumption by 20% and increase thrust by 20-35% compared with the engine without this configuration. And it can ensure that the engine can run stably in subsonic and supersonic conditions.

Description of drawings

FIG. 1 is a schematic diagram of a conventional turbojet engine.

FIG. 2 is a schematic diagram of a conventional turbofan engine.

FIG. 3 is a schematic diagram of the combined layout engine of the variable-cycle and continuously variable-speed drive fans of the present invention.

4 is a schematic diagram of a continuously variable transmission, wherein (a) a small transmission ratio state; (b) a large transmission ratio state.

FIG. 5 is a schematic diagram showing the relationship between the gear ratio and the working line of the fan.

FIG. 6 is a schematic diagram showing the relationship between the nozzle area and the working line of the fan.

In the accompanying drawings, each reference numeral is described as follows:

1- Compressor, 2- Combustion chamber, 3- Turbine, 4- Fan, 5- Continuously variable transmission, 6- Adjustable nozzle, 7- Shaft connected with compressor, 8- Drive wheel set, 9- Connect with fan shaft, 10-driven wheelset

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. Throughout the drawings, the same or similar reference numbers refer to the same or similar elements or elements having the same or similar functions. The described embodiments are a part of the embodiments of the present invention, but not all of the embodiments, and are intended to be used to explain the present invention and should not be construed as a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Combined with the characteristics of the power demand of the unmanned aerial vehicle under multiple operating conditions, for the light-duty power gas turbine engine, the present invention proposes a light-duty power gas turbine engine with a combined layout of variable cycle and continuously variable drive fans. It has the characteristics of high efficiency and low fuel consumption under the power requirements of multi-working conditions of unmanned aerial vehicles.

Figure 1 is a schematic diagram of a conventional turbojet engine. As shown in Figure 1, the main components of the core engine of a conventional turbojet engine include a compressor 1, a combustion chamber 2 and a turbine 3. The turbine 3 is connected to the compressor 1 through a transmission shaft, and the high-temperature gas generated by the combustion chamber 2 drives the turbine 3 to rotate. , the turbine 3 drives the compressor 1 through the transmission shaft. Usually, the engine of this configuration can provide a higher flight speed for the aircraft, but the fuel consumption rate is higher, which is suitable for the high-speed cruise phase of the unmanned aircraft.

Figure 2 is a schematic diagram of a conventional turbofan engine. As shown in Figure 2, the conventional turbofan engine, in addition to the main components of the turbojet engine, namely the compressor 1, the combustion chamber 2 and the turbine 3 that constitute the core engine, also adds a fan 4, which is directly arranged in the transmission The front end of the shaft is provided with two internal and external ducts, and the downstream tail of the core machine is provided with a tail nozzle with a fixed nozzle area. Driven by the fan 4, the air enters the tail nozzle through the inner and outer ducts. The engine of this configuration can provide the aircraft with high efficiency and relatively large thrust, but cannot provide the aircraft with a high speed, which is suitable for the low-speed reconnaissance stage of the unmanned aircraft. Under such an engine configuration, when the UAV performs the transition between high-speed flight and low-speed flight, if only the rotation speed of the transmission shaft is changed, the efficiency will be reduced.

FIG. 3 is a schematic diagram of an engine with a combined layout of the variable-cycle and continuously variable-speed drive fans proposed by the present invention. As shown in FIG. 3 , the gas turbine engine with the combined layout of the variable cycle and continuously variable drive fans of the present invention, compared with the conventional turbofan engine (as shown in FIG. 2 ), adds a non-stop between the compressor 1 and the fan 4 . Step transmission 5, the outlet of the tail nozzle is changed to an adjustable tail nozzle 6, that is, the fan 4 is connected to the drive shaft of the inner core machine through a continuously variable transmission 5, and the tail nozzle is an adjustable tail nozzle with adjustable nozzle area. Nozzle 6. The continuously variable transmission 5 is used to independently adjust the rotational speed of the fan 4, which can separate the rotational speed of the fan 4 from the rotational speed of the inner core machine, so that the inner core machine operates independently in the highest efficiency state. Continuously changing the rotational speed of the fan 4 through the continuously variable transmission 5, and cooperating with the continuously adjustable nozzle area of the adjustable tail nozzle 6, the continuous adjustment of the engine thrust is realized to adapt to the different working conditions of the aircraft. In the process of evaluating the maximum efficiency, the transmission ratio, nozzle area and internal speed are the main parameters that affect the efficiency.

Compared with a gear-driven fan with a fixed transmission ratio, the CVT-driven fan adopted in the present invention has a simple structure, fewer parts, and high reliability. The basic structure of the CVT is shown in FIG. 4 . And the continuously variable transmission can realize the continuous change of the transmission ratio, without being limited by the gear transmission ratio, with the adjustable nozzle, it can realize the continuous change of the thrust, and the flexibility is high. Figure 4 shows the minimum transmission ratio and the maximum transmission ratio respectively. The working schematic diagram of the continuously variable transmission in two states, in the figure, (a) shows the small transmission ratio state, (b) shows the large transmission ratio state, 5 is the continuously variable transmission, and 7 is connected to the compressor. Shaft, 8 is the driving wheel set, 9 is the shaft connected with the fan, and 10 is the driven wheel set. Since the connotation always runs at the maximum efficiency speed in the process, the efficiency is basically not lost with the change of thrust.

Figure 5 shows the relationship between the transmission ratio of the continuously variable transmission and the characteristics of the fan. As the transmission ratio increases, the working line of the fan gradually approaches the stall line. Figure 6 shows the relationship between nozzle area and fan characteristics. As the nozzle area decreases, the fan working line gradually approaches the stall line. The combination of the two can basically make the fan run independently at any operating point within the stable working envelope.

For the variable cycle and infinitely driven fan combined layout engine, it is designed according to the fixed transmission ratio. Since the continuously variable transmission can realize the continuous change of the transmission ratio, multi-stage calculation is required to obtain the overall performance of the engine. Its design method and process are as follows:

SS1. Input flight conditions, engine data and component characteristics;

SS2. Use the engine speed and the β line as the coordinates to interpolate the various parts of the engine (fan, compressor, turbine) to obtain a characteristic map that meets the flight requirements;

SS3. Select the inner speed and transmission ratio;

SS4. Select the fan β line as the outer iteration loop parameter, the β line is the working envelope (linear or parabolic line between the blockage line and the surge line, there is a certain distance between each β line, which has no physical meaning in itself , but its addition introduces an alternative coordinate system, which can help quickly locate the only working point during design, and is a commonly used tool in design;

SS5. Obtain the fan characteristic map and extract the mass flow, pressure ratio and efficiency;

SS6. Calculate the connotation characteristics;

SS7. Read compressor characteristics;

SS8. Select the total inlet temperature before the turbine as the inner loop iteration parameter;

SS9. Calculate combustion chamber characteristics;

SS10. Calculate turbine characteristics;

SS11. Iterate the connotation cycle to ensure the conservation of connotative quality;

SS12. Iterate the import and export cycle to ensure the conservation of import and export quality.

Through the above embodiments, the purpose of the present invention is completely and effectively achieved. Those skilled in the art can understand that the present invention includes but is not limited to the contents described in the accompanying drawings and the above detailed description. Although the present invention has been described with respect to the embodiments presently considered to be the most practical and preferred, it should be understood that the present invention is not limited to the disclosed embodiments, and any modifications that do not depart from the functional and structural principles of the present invention will be included in the claims. within the scope of the book.

Claims (2)

1. An engine with a combined layout of a variable cycle and a continuously variable drive fan, comprising an inner core engine, a fan, two inner and outer ducts, and a tail nozzle, and the inner core engine includes a compressor, a combustion chamber and a turbine, so The turbine is connected to the compressor through a transmission shaft, a fan is arranged upstream of the compressor, a tail nozzle is arranged downstream of the turbine, and air enters the tail nozzle through the inner and outer ducts, It is characterized in that, The fan is drive-connected with the drive shaft of the inner core machine through a continuously variable transmission, The tail nozzle is an adjustable tail nozzle with an adjustable nozzle area, The continuously variable transmission is used to independently adjust the rotational speed of the fan, so that the rotational speed of the fan is separated from the rotational speed of the internal core machine, so that the internal core machine can operate independently in the highest efficiency state, and the continuous By changing the rotational speed of the fan, in conjunction with the continuously adjustable nozzle area of the adjustable tail nozzle, the continuous adjustment of the engine thrust can be realized to adapt to different working conditions of the aircraft; The engine is designed as follows: SS1. Input flight conditions, engine data and component characteristics; SS2. Use the engine speed and beta line as coordinates to interpolate the fan, compressor and turbine in the engine to obtain a characteristic map that meets the flight requirements; SS3. Select the inner speed and transmission ratio; SS4. Select the fan beta line as the outer iteration cycle parameter, and the beta line as the working envelope; SS5. Obtain the fan characteristic map and extract the mass flow, pressure ratio and efficiency; SS6. Calculate the connotation characteristics; SS7. Read compressor characteristics; SS8. Select the total inlet temperature before the turbine as the inner loop iteration parameter; SS9. Calculate combustion chamber characteristics; SS10. Calculate turbine characteristics; SS11. Iterate the connotation cycle to ensure the conservation of connotative quality; SS12. Iterate the import and export cycle to ensure the conservation of import and export quality. 2 . An aircraft, wherein the aircraft comprises the engine of claim 1 . 3 .

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