Turbojet engine air inlet on-off type starting auxiliary method

Abstract

The invention provides a turbojet engine air inlet on-off type starting auxiliary method which comprises a turbojet engine which comprises a core engine, a starting engine, an air inlet channel, an exhaust nozzle and a related control lubrication oil supply auxiliary system. A starting assisting device capable of changing the air inlet blocking or connecting state of the engine in the starting stage is installed on the upstream of the core engine, the air inlet state of the engine is changed in different stages, the acceleration time before ignition of the engine is shortened, the maximum rotating speed selection range before ignition is widened, and starting of the turbojet engine is assisted. According to the air inlet on-off type starting assisting method for the turbojet engine, the actual contribution of energy provided by the starting motor and the like to the acceleration process of the rotor is improved, so that the aims of shortening the time consumption of the acceleration stage of the turbojet engine or improving the selectable range of the ignition rotating speed and the like are achieved, and the starting process of the turbojet engine is assisted.

Description

Technical Field

[0001] The present invention belongs to the field of unmanned power, and particularly relates to a starting assistance method for a turbojet engine with on-off intake air. Background Art

[0002] A turbojet engine is a commonly used power device. Its starting process generally drives the core engine to the ignition speed through an electric starter, a gas turbine starter, an air turbine starter, a powder starter, etc., supplies fuel to the combustion chamber for ignition until the idle speed, and then the starting process ends and the engine runs stably after separating from the starter. For unmanned power platforms such as small and medium-sized unmanned aerial vehicles, starting with an electric starter is a starting solution that takes into account system integration, independence, and safety. However, due to the limitations of small and medium-sized unmanned aerial vehicles, etc., in terms of power-to-weight ratio and volume of the power system, the power level of its starting motor is generally relatively low, reducing the maximum rotational speed limit and angular acceleration of the rotor before engine ignition, forcing designers to select a relatively lower ignition speed under the constraints of starting time, etc., restricting the designers' ignition speed selection range. However, a lower ignition speed reduces the excess air coefficient of the engine and increases the combustion chamber outlet temperature, making it more likely for the engine to have problems such as rich fuel ignition difficulties and engine overheating when facing environments such as high altitudes, affecting the normal starting of the engine. Summary of the Invention

[0003] In view of this, the present invention aims to propose a starting assistance method for a turbojet engine with on-off intake air to solve the problem that the engine cannot start normally.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows: A starting assistance method for a turbojet engine with on-off intake air, including a turbojet engine, which includes a core engine, a starter-generator, an air intake duct, a tail nozzle, and related control, lubrication, and fuel supply auxiliary systems. A starting assistance device capable of changing the blocking or connecting state of the engine intake air during the starting stage is installed upstream of the core engine. By changing the engine intake air state at different stages, the acceleration time before engine ignition is shortened, the maximum rotational speed selection range before ignition is increased, and the starting of the turbojet engine is assisted.

[0005] Further, the initial state of the starting assistance device is set to block the intake air of the core engine; during starting, with the state of the starting assistance device remaining unchanged, the starting motor is started to drive the core engine to accelerate until ready for ignition; the state of the starting assistance device is switched to restore the air supply to the core engine, and the core engine is ignited and subsequent starting operations are performed.

[0006] Further, the starting assistance device can block and connect the intake air of the core engine by changing its own state.

[0007] Further, the installation position of the starting auxiliary device is located at the inlet of the intake duct or between the intake duct and the compressor according to actual requirements.

[0008] Further, the state switching of the starting auxiliary device is any one of electromagnetic control, mechanical control, pneumatic control, and hydraulic control states.

[0009] Further, during the state switching process of the starting auxiliary device, the number of times of changing the on-off state is 1 or more according to actual requirements.

[0010] Further, the on-off control mechanism of the starting auxiliary device is any one of a switch valve-like structure, an adjustable guide vane-like structure, a vector nozzle-like structure, or an integral peeling type plugging structure.

[0011] Compared with the prior art, the intake on-off type starting auxiliary method for a turbofan engine according to the present invention has the following advantages: (1) In the intake on-off type starting auxiliary method for a turbofan engine according to the present invention, by blocking the intake passage during the rotor acceleration stage, unnecessary work consumption such as compressor blowing is reduced during the rotor acceleration stage, and the actual contribution of the energy provided by the starting motor and the like to the rotor acceleration process is improved, thereby achieving the goals of shortening the time-consuming of the acceleration stage of the turbofan engine or expanding the optional range of the ignition speed, etc., and realizing the assistance to the starting process of the turbofan engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 Schematic diagram of the installation position of the starting auxiliary device according to an embodiment of the present invention Figure 1 ; Figure 2 Schematic diagram of the installation position of the starting auxiliary device according to an embodiment of the present invention Figure 2 ; Figure 3 Schematic diagram of the switch valve-like structure according to an embodiment of the present invention; Figure 4 Schematic diagram of the adjustable guide vane-like structure according to an embodiment of the present invention; Figure 5 Schematic diagram of the vector nozzle-like structure according to an embodiment of the present invention Figure 1 ; Figure 6 Schematic diagram of the vector nozzle-like structure according to an embodiment of the present invention Figure 2 . DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0014] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0015] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0016] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0017] A method for starting assistance with on-off intake of a turbojet engine, as Figures 1 to 6 shown, includes a turbojet engine, which includes a core engine, a starter-generator, an air inlet duct, a tail pipe, and related control, lubrication, and fuel supply subsystems. A starting assistance device capable of changing the blocking or connecting state of the engine intake during the starting stage is installed upstream of the core engine. By changing the engine intake state at different stages, the acceleration time before engine ignition is shortened, and the optional range of the maximum speed before ignition is increased to assist the starting of the turbojet engine. The method for starting assistance with on-off intake of a turbojet engine reduces unnecessary work consumption such as compressor blowing during the rotor acceleration stage by blocking the intake passage, improves the actual contribution of the energy provided by the starting motor, etc. to the rotor acceleration process, thereby achieving the goals of shortening the acceleration stage time of the turbojet engine or increasing the optional range of the ignition speed, and realizing the assistance to the starting process of the turbojet engine.

[0018] The initial state of the starting auxiliary device should be set to block the air intake of the core engine; during starting, with the state of the starting auxiliary device remaining unchanged, start the motor to drive the core engine to accelerate until it is ready for ignition; then, the state of the starting auxiliary device is switched to restore the air supply to the core engine, and subsequent starting operations such as core engine ignition are carried out.

[0019] The starting auxiliary device can block and connect the air intake of the core engine by changing its own state; The installation position of the starting auxiliary device can be located at the inlet of the intake duct or between the intake duct and the compressor according to actual requirements.

[0020] The state switching of the starting auxiliary device includes, but is not limited to, control methods such as electromagnetic, mechanical, pneumatic, and hydraulic.

[0021] During the state switching process of the starting auxiliary device, the number of times of changing the on-off state can be 1 or multiple according to actual requirements, and different on-off control mechanisms should be selected for different switching times requirements; Such as Figures 3 to 6 shown, the on-off control mechanism of the starting auxiliary device can specifically include, but is not limited to, a structure similar to a switching valve, a structure similar to an adjustable guide vane, a structure similar to a vector nozzle, or an integral peeling type plugging structure, etc.

[0022] Such as Figure 3 shown, in the schematic diagram of the structure similar to a switching valve, the air intake flows in the left-right direction, and the valve body switches the opening and closing state by rotating around the axis as a whole. The solid line represents the blocking state, and the dotted line represents the ventilation state.

[0023] Such as Figure 4 shown, in the schematic diagram of the structure similar to an adjustable guide vane, the air intake flows in the direction perpendicular to the paper surface, and the valve body switches the opening and closing state by the respective rotation of multiple vanes around the axis. The solid line represents the blocking state, and the dotted line represents the ventilation state.

[0024] Such as Figure 5 and Figure 6 shown, the schematic diagram of the structure similar to a vector nozzle, Figure 5 in which the air intake flows in the direction perpendicular to the paper surface, Figure 6 and in which the air intake direction is left-right flow, and each piece of the valve body rotates around the axis to switch the opening and closing state. The solid line represents the blocking state, and the dotted line represents the ventilation state.

[0025] The integral peeling type plugging structure means that the starting auxiliary device is initially fixed upstream of the intake duct by means of explosive bolts, etc. to block the air intake. After reaching the ignition speed, the starting auxiliary device is integrally separated to restore the air intake of the main engine and start the ignition.

[0026] An implementation method of an air intake on-off type starting auxiliary method for a turbojet engine is as follows: The starting auxiliary device is installed upstream of the core engine; during the acceleration stage before the ignition of the core engine of the turbojet engine, the starting auxiliary device blocks the air intake of the compressor, shortens the time for the core engine speed to increase by reducing the total work done by the core engine on the air during the acceleration stage, and increases the optional range of the maximum speed before the engine ignition; when the speed of the turbojet engine meets the requirements of the subsequent ignition process, the starting auxiliary device terminates the blocking of the air intake passage of the compressor and enables the core engine to return to the normal air intake state to meet the ventilation requirements during the subsequent combustion operation stage.

[0027] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A turbojet engine intake on-off start-up assist method, comprising a turbojet engine, the turbojet engine comprising a core engine, a starter generator, an air intake duct, a tail nozzle and related control lubrication and oil supply auxiliary systems, characterized in that: A starting assist device is installed upstream of the core engine, which is capable of changing the blocked or connected state of the engine intake during the starting phase. By changing the engine intake state at different stages, the acceleration time before engine ignition is shortened, and the maximum speed selection range before ignition is increased, thereby assisting the starting of the turbojet engine.

2. A turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The initial state of the starting auxiliary device is set to block the core engine's air intake; when starting, the motor is started while keeping the state of the starting auxiliary device unchanged, driving the core engine to accelerate until it is ready for ignition; the state of the starting auxiliary device is switched to restore the core engine's air supply, and the core engine is ignited and subsequent starting operations are performed.

3. A turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The starting assist device can block and connect the air intake of the core engine by changing its own state.

4. A turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The installation position of the starting aid device is located at the inlet of the air intake duct or between the air intake duct and the compressor according to actual needs.

5. The turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The state of the starting assist device is switched to any one of electromagnetic control, mechanical control, pneumatic control, and hydraulic control.

6. A turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The state switching process of the starting auxiliary device changes the on-off state once or multiple times according to actual needs.

7. A turbojet engine intake on-off starting assistance method according to claim 1, characterized in that: The on-off control mechanism of the starting auxiliary device is any one of a switch valve-like structure, an adjustable guide vane-like structure, a vector nozzle-like structure or an integral peeling type blocking structure.

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