Multi-wave rotary detonation engine isolation section simulation calculation method based on rotary heat source

Abstract

The invention discloses a multi-wave rotary detonation engine isolation section analog calculation method based on a rotary heat source, which comprises the following steps: step 1, carrying out three-dimensional modeling on an isolation section to obtain an isolation section digital model; the isolation section digital model is at least provided with two heat sources, and the heat sources are used for simulating detonation waves rotating in the same direction or opposite directions; step 2, performing grid division on the isolation section digital model by using grid drawing software, and inputting the isolation section digital model after grid division into fluid simulation software; 3, giving a flow field control equation; and 4, giving boundary conditions, initial conditions, heat source motion conditions and heat source heat release conditions, and performing calculation simulation on the isolation section of the rotary detonation engine to obtain a simulation calculation result. Motion shock wave development and evolution structures in an isolation section under various combustion conditions of the multi-wave rotary detonation engine can be simulated, the applicable working conditions are rich, the simulation calculation method is simple in condition setting, the calculation stability is high, and high-precision calculation is adapted.

Description

Technical Field

[0001] This invention relates to the field of simulation calculation technology for the isolation section of a rotating detonation engine, and in particular to a simulation calculation method for the isolation section of a multi-wave rotating detonation engine based on a rotating heat source. Background Technology

[0002] With the development of civilian and military aerospace science and technology, various aerospace vehicles are placing increasingly stringent requirements on the specific impulse, economy, and environmental performance of their propulsion systems, namely engines. However, limited by the thermal load capacity of materials, traditional engines based on isobaric combustion are approaching their upper limits in terms of specific impulse and environmental performance. To further improve engine propulsion performance, multi-wave rotating detonation engines based on detonation combustion, serving future multi-condition, wide-range aircraft, have emerged. These engines employ multiple high-speed detonation waves (≥2 in number, >1000 m / s) in the combustion chamber to replace the traditional stationary combustion wave structure, achieving complete fuel combustion in a very short time. This not only further improves engine propulsion efficiency and simplifies the engine combustion chamber structure but also significantly shortens the duration of high-temperature zones within the combustion chamber, thus reducing the heat load on the combustion chamber and decreasing NO₂ levels. x Pollutant emissions.

[0003] The intake duct, located at the very top of the engine, is the device used for efficient air compression. The stability of its flow field directly determines the stability of the engine's operation. The isolator, located between the intake duct and the rotating detonation combustion chamber in a rotating detonation engine, is a flow channel used to isolate the combustion chamber from the intake duct's influence, playing a crucial role in maintaining the intake duct's stability. While the high-speed detonation waves within the combustion chamber improve fuel combustion performance, they also significantly impact the operational stability of the isolator and the intake duct. Because the unidirectional or opposing detonation waves within the combustion chamber inevitably induce multiple high-speed shock waves propagating towards the isolator, a complex multi-channel shock wave / boundary layer interference phenomenon forms within the isolator. Improper control of the rotating shock waves can induce large separation vortices within the isolator, further causing intake duct start-up issues and severely degrading engine performance. Therefore, simulation studies on the multi-channel rotating shock wave / boundary layer interference phenomenon in the isolation section of a multi-wave rotating detonation engine are increasingly becoming a hot research topic in the field of aerospace science and technology. The efficient and low-cost simulation method for the isolation section of a multi-wave rotating detonation engine has broad application prospects.

[0004] However, in traditional research on the isolator section of multi-wave rotating detonation engines, in order to induce the generation of multi-guided rotating shock waves within the isolator section, the common methods are to set the isolator section outlet as a rotating pressure outlet or to set up a rotating detonation combustion chamber at the isolator section outlet for detonation combustion. Of these two methods, setting the isolator section outlet as a rotating pressure outlet is simple to set up and has high computational stability, but it can only induce shock waves moving in the same direction at most, making it difficult to extend to the generation of opposing shock waves. On the other hand, setting up a rotating detonation combustion chamber at the isolator section outlet requires the introduction of a chemical reaction, which makes its setup difficult, computationally unstable, and prone to failure in inducing rotating shock wave generation due to improper chemical reaction equation settings. Furthermore, it is difficult to study using high-precision simulation software and methods. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned shortcomings, this invention provides a simulation calculation method for the isolation section of a multi-wave rotating detonation engine based on a rotating heat source. This method is simple to set up, computationally stable, widely applicable, and easy to implement with high precision.

[0006] Technical Solution: To solve the above problems, this invention employs a simulation calculation method for the isolation section of a multi-wave rotating detonation engine based on a rotating heat source, comprising the following steps:

[0007] Step 1: Perform three-dimensional modeling of the isolation section to obtain a digital model of the isolation section; the digital model of the isolation section shall be provided with at least two heat sources, which are used to simulate detonation waves rotating in the same or opposite directions;

[0008] Step 2: Use mesh drawing software to generate a mesh for the isolation section digital model, and then input the meshed isolation section digital model into the fluid simulation software;

[0009] Step 3: Given the flow field control equations;

[0010] Step 4: Given the boundary conditions, initial conditions, heat source motion conditions, and heat source heat release conditions, perform calculation simulation on the isolation section of the rotating detonation engine and obtain the simulation calculation results.

[0011] Furthermore, the digital model of the isolation section includes the isolation section and a heat source generation area connected to the isolation section, with the heat source located within the heat source generation area.

[0012] Furthermore, the specific steps for setting up the heat source are as follows: a heat source model is set up in the heat source generation area, and the heat source model is set to have a preset heat source intensity q.

[0013] Furthermore, the isolation section includes a coaxially arranged cylindrical inner wall and a cylindrical outer wall, which surround each other to form an annular isolation section channel; an annular heat source generation area is connected to one side of the isolation section channel.

[0014] Furthermore, the isolation section includes a hollow cylindrical shell, inside which is a cylindrical isolation section channel, and a cylindrical heat source generation area is connected to one side of the isolation section channel.

[0015] Furthermore, the governing equations of the flow field include the mass conservation equation and the Euler equation:

[0016]

[0017]

[0018] in For density, For time, Let x, y, and z be the velocities. For volume forces in the x, y, and z directions.

[0019] Furthermore, the boundary conditions include the flow rate and pressure of the fluid entering the isolation section inlet and the pressure at the outlet of the heat source generation area.

[0020] Furthermore, the initial conditions include the state of the fluid within the isolation section channel and the heat source generation zone, which includes a static state or a dynamic state.

[0021] Furthermore, the heat source motion conditions include the number of heat sources, the rotational direction of each heat source, and the rotational period T of each heat source.

[0022] Furthermore, the heat release conditions of the heat source include the release of energy per unit volume of heat source per unit time.

[0023] Beneficial effects: Compared with the prior art, the significant advantage of this invention is that it can simulate the development and evolution structure of the motion shock wave in the isolation section of a multi-wave rotating detonation engine under various combustion conditions such as co-directional double wave, co-directional multi-wave, collision double wave, and collision multi-wave. It is applicable to a wide range of working conditions, has simple simulation calculation method and condition settings, high calculation stability, and is compatible with high-precision calculation. It will greatly improve and assist the design and research of the isolation section of rotating detonation engines. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the 3D model of the isolation section in this embodiment;

[0025] Figure 2 This is a schematic diagram of the timing and location of the heat source during one rotational motion cycle under the same-direction dual-wave condition.

[0026] Figure 3 This is a schematic diagram of the timing and location of the heat source during one rotational motion cycle under the same-direction wave condition.

[0027] Figure 4 This is a schematic diagram showing the result after simulating the isolation section of a dual-wave rotating detonation engine in the same direction in this embodiment. Detailed Implementation

[0028] This embodiment presents a simulation calculation method for the isolation section of a multi-wave rotating detonation engine based on a rotating heat source, comprising the following steps:

[0029] Step 1: Perform 3D modeling of the isolation section to obtain a digital model of the isolation section. The digital model of the isolation section includes the isolation section and a heat source generation area 4 connected to the isolation section, with the heat source set within the heat source generation area 4. The digital model of the isolation section can be set as an annular or cylindrical shape. Specifically, if it is an annular shape, the isolation section includes a coaxially arranged cylindrical inner wall 7 and cylindrical outer wall 8, which surround to form an annular isolation section channel 2; the annular heat source generation area 4 is connected to one side of the isolation section channel 2. If it is cylindrical, the isolation section includes a hollow cylindrical outer shell, the interior of which is a cylindrical isolation section channel, and a cylindrical heat source generation area is connected to one side of the isolation section channel. In this embodiment, the digital model of the annular isolation section is obtained using UG modeling software, as shown below. Figure 1 As shown, the front end of the obtained isolation section digital model is the isolation section inlet 1, the end of the isolation section channel is the isolation section outlet 3, the isolation section outlet 3 is also the inlet of the heat source generation zone 4, and the end of the heat source generation zone 4 is the heat source generation zone outlet 5.

[0030] The heat source can be placed on the inner or outer wall of the heat source generation area 4. The specific steps are as follows: A heat source model is set within the heat source generation area 4, and this model is given a preset heat source intensity q. The number of heat sources is adjusted according to the operating conditions to be simulated. For simulating a dual-wave mode, two heat sources are set; for a multi-wave mode, multiple heat sources are set. The heat source intensity can also be adjusted. In this embodiment, two heat sources (6.1, 6.2) are set to simulate the dual-wave mode.

[0031] Step 2: Use mesh generation software to create a mesh for the isolation section digital model, and then input the meshed isolation section digital model into the fluid simulation software. In this embodiment, the mesh generation software is ICEM, and the fluid simulation software is OpenCFD.

[0032] Step 3: Given the governing equations of the flow field. The governing equations of the flow field include the mass conservation equation and the Euler equation:

[0033]

[0034]

[0035] in For density, For time, Let x, y, and z be the velocities. For volume forces in the x, y, and z directions.

[0036] Step 4: Given the boundary conditions, initial conditions, heat source motion conditions, and heat source heat release conditions, perform a simulation calculation on the isolation section of the rotating detonation engine to obtain the simulation results. Boundary conditions include the flow velocity and pressure of the fluid entering the isolation section inlet and the pressure at the outlet of the heat source generation region. Initial conditions include the state of the fluid within isolation section channel 2 and heat source generation region 4, which can be either static or dynamic. Heat source motion conditions include the number of heat sources, the rotational direction of each heat source, and the rotational period T of each heat source. Heat source heat release conditions include the energy released per unit volume of heat source per unit time.

[0037] The rotational motion direction of the heat source includes clockwise rotation and counterclockwise rotation. In dual-wave mode, two heat sources can be set to move in the same direction or in opposite directions. In multi-wave mode, the motion direction of each heat source can be set according to specific needs. They can all be set to the same motion direction or to different motion directions. Figure 2 This is a schematic diagram illustrating the timing and location of the heat source during a single rotational motion cycle in a dual-wave operating condition. Figure 3 This is a schematic diagram illustrating the timing and location of the heat source during a single rotational motion cycle in a counter-current dual-wave operating condition.

[0038] Taking the simulated co-directional dual-wave operation as an example, the fluid entering the inlet 1 of the rotating detonation engine isolation section is set to a Mach number of 2 and a pressure of 100 kPa, while the pressure leaving the outlet 5 of the rotating heat source generation region is 782 kPa. Initially, the fluid in the rotating detonation engine isolation section channel and the rotating heat source generation region is stationary. The number of rotating heat source generation regions is 2, and each T = 2 × 10⁻⁶ -4 When s rotates in the same direction for one revolution, the heat source intensity q is 20 J / (m²). 3 ·s).

[0039] The final simulation results of the above-mentioned dual-wave operating condition are as follows: Figure 4 As shown, the longitudinal Mach number of the isolation section decreases to subsonic speed after passing through a normal shock wave near the inlet of the isolation section, and then decreases gradually along the flow direction without separation, proving that the flow field in the isolation section is successfully established; the pressure distribution on the isolation section wall shows two spiral pressure step boundary lines, proving that the co-rotating heat source successfully induces two co-rotating shock waves propagating upstream; the above results prove that the simulation method based on the rotating heat source in this example can be used for simulation research of the isolation section of a multi-wave rotating detonation engine.

Claims

1. A method for simulation of a rotating detonation engine isolator section of a multi-wave rotating detonation engine based on a rotating heat source, characterized in that, The method comprises the following steps: Step 1, three-dimensional modeling of the isolation section to obtain a digital model of the isolation section; the digital model of the isolation section is provided with at least two heat sources for simulating co-rotating or counter-rotating detonation waves; Step 2, meshing the digital model of the isolation section by using mesh drawing software, and inputting the meshed digital model of the isolation section into a fluid simulation software; Step 3, giving a flow field control equation; Step 4, giving boundary conditions, initial conditions, heat source motion conditions and heat source heat release conditions to calculate and simulate the isolation section of the rotary detonation engine, and obtaining simulation calculation results.

2. The simulated calculation method of the multiple-wave rotary detonation engine isolated section according to claim 1, characterized in that, The digital model of the isolation section comprises an isolation section, a heat source generation area (4) connected to the isolation section, and the heat source is arranged in the heat source generation area (4).

3. The simulated calculation method of the multiple-wave rotary detonation engine isolated section according to claim 2, characterized in that, The specific arrangement steps of the heat source are: arranging a heat source model in the heat source generation area (4), and arranging the heat source model to have a preset heat source intensity q.

4. The simulated calculation method of a multiple-wave rotating detonation engine isolation section of claim 2, wherein, The isolation section comprises a cylindrical inner wall (7) and a cylindrical outer wall (8) arranged coaxially, and the cylindrical inner wall (7) and the cylindrical outer wall (8) surround to form a circular annular isolation section channel (2); the isolation section channel (2) is connected with a circular annular heat source generation area (4) on one side.

5. The simulated calculation method of a multiple-wave rotating detonation engine isolation section of claim 2, wherein, The isolation section comprises an internally hollow cylindrical shell, and the inside of the cylindrical shell is a cylindrical isolation section channel (2), and the isolation section channel (2) is connected with a cylindrical heat source generation area (4) on one side.

6. The simulated calculation method of a multiple-wave rotating detonation engine isolation section of claim 1, wherein, The flow field control equation comprises a mass conservation equation and an Euler equation: wherein is the density, is the time, is the velocity in the three directions xyz, is the volume force in the three directions xyz.

7. The simulated calculation method of a multiple-wave rotating detonation engine section of claim 1, wherein, The boundary conditions include the flow velocity and pressure of the fluid entering the isolation section inlet, and the pressure of the heat source generation area outlet.

8. The simulated calculation method of a multiple-wave rotary detonation engine isolation section of claim 1, wherein, The initial conditions include the state of the fluid in the isolation section channel (2) and the heat source generation area (4), and the state includes a stationary state or a moving state.

9. The simulated calculation method of a multiple-wave rotary detonation engine isolation section of claim 1, wherein, The heat source motion condition includes the number of heat sources, the rotating motion direction of each heat source, and the rotating motion period T of each heat source.

10. The simulated calculation method of a multiple-wave rotating detonation engine section of claim 1, wherein, The heat source heat release condition includes the energy released by the unit volume of the heat source per unit time.

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