A detonation engine intake duct with a partial partition

Abstract

The present invention provides a detonation engine intake duct with a partial baffle, comprising an intake duct and a baffle. The intake duct is a convergent-divergent duct; the baffle is arranged in the motion shock wave interference area within the intake duct, partially dividing the intake duct into two flow channels, so that a motion shock wave is divided into two motion shock waves with inconsistent motion, reducing the pressure difference before and after the shock wave, reducing the intensity of the motion shock wave, thereby effectively suppressing the forward transmission of the motion shock wave, reducing the pressure pulsation intensity, and improving the stability of the detonation engine. Compared with the original intake duct scheme, the motion shock wave suppression technology proposed in the present invention does not require the provision of additional energy, has a simple structure, and is economical, and plays an important role in expanding the stable operating margin of the detonation engine.

Description

Technical Field

[0001] The present invention relates to the technical field of detonation engine design, in particular to the field of detonation engine intake duct flow control. Background Art

[0002] Detonation combustion has high thermal cycle efficiency, low fuel consumption, and the characteristics of self-pressurization and high energy release rate, making it a current research hotspot. Pulse detonation engines and rotating detonation engines that use detonation combustion generate high-frequency detonation waves in their combustion chambers. In the intake duct upstream of the combustion chamber, there is a strong pressure disturbance that propagates upstream. This strong disturbance manifests as a moving shock wave. The high-frequency unsteady flow dominated by this moving shock wave brings strong unsteady excitation to the upstream intake duct and the combined engine turbulent flow duct, affecting the stable operation of the engine. If the intensity of this moving shock wave is too high, its disturbance may be transmitted to the upstream of the intake throat, causing deterioration of engine performance and even failure to operate normally and stably. Therefore, it is necessary to suppress the forward transmission of this strong pressure disturbance and control the moving shock wave / boundary layer interference in the intake duct to maintain the macroscopic stability of the flow, thereby improving the stability and performance of the engine operation.

[0003] Currently, extensive research has been conducted on detonation combustion, including experimental and simulation methods and flow mechanisms. Detonation engine design has also made significant progress, entering the engineering development phase. However, relatively little research has been conducted on technologies for suppressing the strong pressure disturbances in the intake duct. Therefore, there is a need to develop technologies for suppressing the shock waves in the intake duct of a detonation engine. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a detonation engine intake duct with a local baffle, the purpose of which is to reduce the intensity of the forward motion shock wave.

[0005] To achieve the above-mentioned purpose, the detonation engine intake duct with a partial partition provided by the present invention can adopt the following scheme:

[0006] A detonation engine intake duct with a partial baffle, the intake duct is a section of convergent-divergent pipe, which accelerates a subsonic inlet to a supersonic speed; a partial baffle (2) of equal thickness is installed in the intake duct; the placement direction of the partial baffle is the same as the direction of the airflow, and the two sides of the partial baffle are respectively fixed to the two inner walls of the intake duct; the horizontal distance D between the center of the partial baffle and the outlet of the intake duct is 38.7% of the length d of the expansion section of the intake duct, that is, D = 38.7% × d, and the partial baffle is placed at the center line of the flow channel; the length of the partial baffle is three times the height of the flow channel outlet.

[0007] Furthermore, the local partition is rounded and passivated at both ends along the airflow direction.

[0008] Furthermore, the intake duct is divided into two flow channels by a local partition at the location of the partition.

[0009] Beneficial effects:

[0010] Compared with the prior art, the present invention divides the intake duct into two partial flow channels by arranging local baffles at appropriate positions in the flow direction and height direction. A series of moving shock waves exist in each of the two flow channels. Due to the different geometric aerodynamic parameters such as the flow channel area and flow rate, the propagation speed of the moving shock waves is also different, forming two moving shock waves with inconsistent positions upstream of the baffle, reducing the pressure difference before and after the moving shock wave, thereby weakening the intensity of the moving shock wave and reducing the intensity of the pressure pulsation. The present invention can effectively reduce the intensity of the forward moving shock wave, achieving the purpose of rapid attenuation of the moving shock wave and rapid reduction of the pressure pulsation intensity, which is conducive to shortening the length of the intake duct, reducing the structural weight, and enhancing the operating stability of the detonation engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present invention.

[0012] Figure 2 This is a schematic diagram of the installation position of the local partition

[0013] Figure 3 It is the working condition at the flow channel outlet.

[0014] Figure 4 This is a comparison diagram of the instantaneous flow field of the intake duct of the present invention.

[0015] Figure 5 It is a comparison curve of pulsation intensity along the intake duct with / without partial baffle.

[0016] In the figure, 1 refers to the intake duct; 2 refers to the local partition. DETAILED DESCRIPTION

[0017] See Figure 1 、 Figure 2 and Figure 3 , which is an embodiment of a detonation engine intake duct with a partial baffle according to the present invention. The detonation engine intake duct comprises an intake duct 1 and a partial baffle 2.

[0018] The horizontal distance D between the center of the local partition and the outlet of the intake duct is 38.7%. The length d of the expansion section of the intake duct is the first key to the present invention, that is, D = 38.7% × d.

[0019] Placing the local partition at the center line of the flow channel is the second key to the present invention.

[0020] The third key point of the present invention is that the length of the local partition is three times the height of the flow channel outlet.

[0021] The placement direction of the local partition is the same as the direction of the airflow, and the ends along the airflow direction are rounded and passivated. The equal thickness design is the fourth key to the present invention.

[0022] These four key points are essential to form a complete technical solution. While maintaining a nearly constant total pressure recovery coefficient, this technical solution effectively suppresses the forward propagation of moving shock waves, reduces pressure pulsation intensity, and significantly improves intake duct operation stability. The following application example demonstrates the effectiveness of this technology in a specific detonation intake duct.

[0023] Example

[0024] Working conditions at the export Figure 2 In the example shown, the detonation intake duct inlet height is 73 mm, and the outlet height H is 80 mm. A partial baffle is installed at the centerline of the duct, oriented in the same direction as the incoming airflow. The baffle is designed with uniform thickness and rounded and passivated at both ends along the airflow direction. The baffle is 2 mm thick and 240 mm long. The horizontal distance D between the center of the baffle and the intake duct outlet is 400 mm. Figure 4 and Figure 5 The flow field diagrams and corresponding pulsation intensity changes along the intake duct before and after the installation of the partial baffle are compared. Table 1 compares the intake duct performance parameters before and after the installation of the partial baffle. After adopting the shock wave forward transmission suppression measure with the partial baffle, the total pressure recovery coefficient σ of the intake duct decreases by 0.1%, and the pulsation intensity ε decreases to 33.3% of the original solution. Figure 5 The results show that the present invention can effectively suppress the forward transmission of the moving shock wave, reduce the intensity of the pressure pulsation, and significantly improve the stability of the intake duct while ensuring that the total pressure recovery coefficient remains basically unchanged.

[0025] Table 1

[0026] Pulsation intensity ε Total pressure recovery coefficient σ Original Plan A 0.048 0.857 Adopt Suppression Measures Option B 0.016 0.856

[0027] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as “center” and “horizontal” are based on the orientations or positional relationships shown in the accompanying drawings, and are 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 cannot be understood as a limitation on the present invention.

[0028] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A detonation engine intake duct with a partial baffle, characterized by: The intake duct is a converging and diverging pipe, which accelerates the subsonic inlet airflow to supersonic speed; a local baffle (2) of equal thickness is installed in the intake duct; the placement direction of the local baffle is the same as the airflow direction and the two sides of the local baffle are respectively fixed to the two inner walls of the intake duct; the horizontal distance D between the center of the local baffle and the outlet of the intake duct is 38.7% of the length d of the expansion section of the intake duct; that is, D = 38.7% × d, and the local baffle is placed at the center line of the flow channel; the length of the local baffle is 3 times the height of the flow channel outlet; the local baffle is rounded and passivated at both ends along the airflow direction.

2. The detonation engine intake duct with a partial baffle according to claim 1, characterized in that: The intake duct is divided into two flow channels by a partial partition at the location of the partial partition.

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