Design method of large-scale cavity flame holder considering scale effect

Abstract

The application discloses a large-scale concave cavity flame stabilizer design method considering scale effect, and comprises the following steps: obtaining an amplification coefficient based on the inlet inner diameter of a target scale concave cavity flame stabilizer and a reference small-scale concave cavity flame stabilizer, isometrically enlarging the reference small-scale concave cavity flame stabilizer to the target scale, correcting the concave cavity depth, and obtaining a first intermediate scale concave cavity flame stabilizer; correcting the concave cavity depth based on the relative thickness of a flow boundary layer, and obtaining a second intermediate scale concave cavity flame stabilizer; correcting the concave cavity length and the trailing edge inclination angle based on the fuel chemical properties, and obtaining a third intermediate scale concave cavity flame stabilizer; and correcting the concave cavity length, the leading edge depth and the trailing edge height based on the wall heat transfer rate, and obtaining the target scale concave cavity flame stabilizer. The application is applied to the field of engine design, and can realize the rapid design of the large-scale concave cavity flame stabilizer by considering the influence of scale effect of various factors under the premise of ensuring the stable flame capacity and the combustion efficiency.

Description

Technical Field

[0001] The present invention relates to the field of engine design technology, and in particular to a design method for a large-scale cavity flame stabilizer that takes into account the scale effects of factors such as the thickness of the incoming flow boundary layer, the chemical properties of the fuel, and the wall heat transfer rate. Background Art

[0002] Maintaining flame stability under high-speed airflow conditions is a prerequisite for efficient scramjet combustion. Incorporating a concave cavity into the combustion chamber wall is a commonly used non-invasive flame stabilizer solution for these high-speed airflow conditions. The cavity structure offers low flow resistance and excellent flame stabilization. The cavity provides a low-speed recirculation zone within the cavity, which, combined with the lateral injection of fuel jets from the combustion chamber wall, effectively enhances fuel mixing and effectively contains the flame.

[0003] As engine scale changes, the flame stabilization process in the combustion chamber exhibits significant scale effects. Considering the impact of scale effects in the inherently complex supersonic mixed combustion process and developing a broadly applicable design approach is extremely challenging. For a long time, the selection of cavity flame stabilizers for large-scale engines has often relied on engineering experience, directly scaling up the geometry of smaller engines without a reliable theoretical basis. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the existing technology, the present invention provides a design method for a large-scale cavity flame stabilizer taking into account the scale effect. Based on the existing small-sized cavity combustion chamber configuration, while ensuring that the flame stabilization capability and combustion efficiency remain unchanged, the influence of multiple factors under the scale effect is considered to achieve rapid design of the large-scale cavity flame stabilizer configuration.

[0005] To achieve the above objectives, the present invention provides a design method for a large-scale concave cavity flame stabilizer taking into account the scale effect, comprising the following steps:

[0006] Step 1: obtaining an amplification factor based on an inlet inner diameter of a target-scale concave cavity flame stabilizer and an inlet inner diameter of a reference small-scale concave cavity flame stabilizer;

[0007] Step 2: scaling up the reference small-scale concave cavity flame stabilizer to a target scale based on the magnification coefficient, and correcting the cavity depth to obtain a first intermediate-scale concave cavity flame stabilizer;

[0008] Step 3: Based on the first intermediate-scale concave cavity flame stabilizer, the cavity depth is corrected based on the relative thickness of the incoming flow boundary layer to obtain a second intermediate-scale concave cavity flame stabilizer;

[0009] Step 4: Based on the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are corrected according to the chemical properties of the fuel to obtain a third intermediate-scale concave cavity flame stabilizer;

[0010] Step 5: Based on the third intermediate-scale cavity flame stabilizer, based on the wall heat transfer rate and under the premise that the cavity length-to-depth ratio remains unchanged, the cavity length, leading edge depth and trailing edge height are corrected to obtain the target-scale cavity flame stabilizer.

[0011] In one embodiment, step 2 is specifically as follows:

[0012] On the basis of the benchmark small-scale concave cavity flame holder, the inlet inner diameter, the cavity length and the outlet inner diameter are linearly enlarged by n times, the leading edge depth is sublinearly enlarged by x times, and the trailing edge height is made to follow the leading edge depth while keeping the trailing edge inclination angle unchanged, thereby obtaining the first intermediate-scale concave cavity flame holder;

[0013] Wherein, n is the amplification factor, and x is the sublinear amplification factor.

[0014] In one embodiment, the sublinear amplification factor x is specifically

[0015] In one embodiment, step 3 is specifically as follows:

[0016] A relative change rate θ of the incoming flow boundary layer thickness of the first intermediate-scale concave cavity flame stabilizer is obtained based on numerical simulation or experimental observation;

[0017] On the basis of the first intermediate-scale concave cavity flame stabilizer, the leading edge depth is multiplied by a coefficient 1+θ, and the trailing edge height is made to follow the change of the leading edge depth, thereby obtaining the second intermediate-scale concave cavity flame stabilizer.

[0018] In one embodiment, step 4 is specifically as follows:

[0019] If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, the second intermediate-scale concave cavity flame stabilizer is directly used as the third intermediate-scale concave cavity flame stabilizer;

[0020] If the fuel of the target-scale concave cavity flame stabilizer is hydrogen and / or ethylene, then based on the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are increased by 3%-4%, thereby obtaining the third intermediate-scale concave cavity flame stabilizer;

[0021] If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, ethylene and / or kerosene, then on the basis of the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are both increased by 9%-10%, thereby obtaining the third intermediate-scale concave cavity flame stabilizer.

[0022] In one embodiment, step 5 is specifically as follows:

[0023] On the basis of the third intermediate scale concave cavity flame stabilizer, the cavity length and the leading edge depth are multiplied by the coefficient 1-n / 50×0.81, and the trailing edge height is made to follow the leading edge depth, so as to obtain the target scale concave cavity flame stabilizer, wherein n is the amplification coefficient.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The present invention is based on the existing small-sized concave cavity combustion chamber configuration. On the premise of ensuring that the flame stabilization capability and combustion efficiency remain unchanged, it integrates the influence of the scale effect of multiple factors such as the incoming flow boundary layer thickness, fuel chemical properties, and wall heat transfer rate to achieve the rapid design of the large-scale concave cavity flame stabilizer configuration. It can effectively reduce the required concave cavity flame stabilizer size and the overall engine size while maintaining the flame stabilization capability, reduce the thermal protection area, and enhance combustion robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a flow chart of a design method for a large-scale cavity flame stabilizer taking into account scale effect in an embodiment of the present invention;

[0028] Figure 2 The enlarged front and rear cross-sectional dimensions of the concave cavity flame stabilizer in the embodiment of the present invention;

[0029] Figure 3 Schematic diagram of a fitting curve of Da2 / Da1 and amplification factor k1 in an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of a fitting curve of Da2 / Da1 and amplification factor k2 in an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the fitting curve of Da2 / Da1 and the amplification factor n in an embodiment of the present invention.

[0032] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0034] It should be noted that all directionality indications (such as up, down, left, right, front, back, and the like) in the embodiments of the present application are only used to explain the relative position relationship, movement condition and the like between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0035] In addition, the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0036] The embodiment discloses a large-scale cavity flame stabilizer design method considering the effect of scale effect, aiming to quickly design a larger scale cavity combustion chamber with the same flame stabilization capacity and combustion efficiency by using the existing small scale cavity combustion chamber configuration parameters, so as to avoid the interference of combustion process dissimilarity (i.e. scale effect) caused by direct geometric linear amplification.

[0037] Reference Figure 1 The large-scale cavity flame stabilizer design method considering the effect of scale effect in the embodiment includes the following steps:

[0038] Step 1, obtaining an amplification coefficient based on the inlet inner diameter of the target scale cavity flame stabilizer and the inlet inner diameter of the reference small scale cavity flame stabilizer;

[0039] Step 2, isometrically enlarging the reference small scale cavity flame stabilizer to the target scale based on the amplification coefficient and correcting the cavity depth to obtain a first intermediate scale cavity flame stabilizer;

[0040] Step 3, correcting the cavity depth based on the relative thickness of the incoming flow boundary layer on the basis of the first intermediate scale cavity flame stabilizer to obtain a second intermediate scale cavity flame stabilizer;

[0041] Step 4, correcting the cavity length and the trailing edge angle based on the fuel chemical properties on the basis of the second intermediate scale cavity flame stabilizer to obtain a third intermediate scale cavity flame stabilizer;

[0042] Step 5: Based on the third intermediate-scale cavity flame stabilizer, based on the wall heat transfer rate and under the premise that the cavity length-to-depth ratio remains unchanged, the cavity length, leading edge depth and trailing edge height are corrected to obtain the target-scale cavity flame stabilizer.

[0043] For example Figure 2 As shown, the inlet inner diameter of the existing benchmark small-scale concave cavity flame stabilizer is d1, the outlet inner diameter is d2, the concave cavity length is l, the leading edge depth is h1, the trailing edge height is h2 and the trailing edge inclination angle α are all known parameters, and the inlet inner diameter df1 of the target-scale concave cavity flame stabilizer is a known parameter, and the amplification coefficient n = df1 / d1 can be obtained.

[0044] In the specific implementation process of step 2, based on the benchmark small-scale concave cavity flame stabilizer, the inlet inner diameter, the cavity length and the outlet inner diameter are linearly amplified by n times, the leading edge depth is sublinearly amplified by x times, and the trailing edge height is made to follow the leading edge depth, while keeping the trailing edge inclination angle unchanged, thus obtaining the first intermediate-scale concave cavity flame stabilizer. Wherein, x is the sublinear amplification coefficient, and the sublinear amplification coefficient x is specifically

[0045] For example, let the inlet inner diameter of the first intermediate-scale concave cavity flame stabilizer be d 1-1 , the outlet inner diameter is d 2-1 , the cavity length is l1, the front edge depth is h 1-1 , the trailing edge height is h 2-1 With the trailing edge inclination angle α1, the configuration parameters of the first intermediate scale cavity flame stabilizer are: 1-1 =n·d1,d 2-1 =n·d2, l1=n·l, α1=α, the trailing edge height is h 2-1 Following the leading edge depth h 1-1 Change, that is, the trailing edge height is h 2-1 The value is selected so that the bottom wall of the first intermediate-scale concave cavity flame stabilizer is parallel to the axial direction of the first intermediate-scale concave cavity flame stabilizer.

[0046] Da is a similar parameter that can be used to describe the flame stabilization of the cavity. If the two combustion chambers If the numbers are equal, then the two physical phenomena can be considered similar, that is, the cavity has the same flame stabilization effect. This embodiment defines a dimensionless number q to measure whether the flame stabilization effect of the cavity is similar to that of the basic example when the combustion chamber is scaled. The closer it is to 1, the higher the similarity, that is:

[0047] q=Da2 / Da1

[0048] Among them, Da2 is the combustion chamber after amplification Number, Da1 is the number before the combustion chamber is enlarged number;

[0049] In the specific implementation process, The calculation process of Da is:

[0050]

[0051] Where D is the depth of the cavity, U A is the axial velocity of the air flow on the air side, τ NP is the flame time scale;

[0052] In the process of calculating the sublinear amplification factor x, we first consider Among them, k1 is the expansion coefficient of the cavity depth when the combustion chamber is expanded n times as a whole, k2 is the expansion coefficient of the recirculation zone length when the combustion chamber is expanded n times as a whole, and a, b, and c are the parameters to be fitted.

[0053] The combustion chamber in this embodiment adopts the lean-burn Davis-transverse jet model. On this basis, data fitting is performed according to the preset inlet flow gas specific heat ratio, inlet flow gas constant, inlet flow total temperature, inlet flow static pressure, inlet flow Mach number, inlet flow static temperature, inlet flow velocity, inlet flow air density, cavity depth, recirculation zone length, cavity leading edge span width, and fuel mass flow rate. The fitting structure is as follows: Figures 3 to 5 As shown, we can get To make need That is, under lean combustion conditions, when the cavity length and the recirculation zone length are magnified n times, the cavity depth is scaled. times.

[0054] During the specific implementation of step 3, considering the influence of the relative thickness of the incoming flow boundary layer, the enlargement of the cavity scale will cause the relative thickness of the boundary layer upstream of the cavity to the vicinity of the cavity leading edge to become thinner, thereby making the cavity shear layer relatively thinner and weakening the effect of fuel entrainment into the cavity recirculation zone. The relative change rate of the incoming flow boundary layer thickness is determined by the inlet inner diameter and the amplification factor of the reference small-scale cavity flame stabilizer. Specifically, in this embodiment, the relative change rate θ of the incoming flow boundary layer thickness of the first intermediate-scale cavity flame stabilizer is first obtained based on numerical simulation or experimental observation. Then, based on the first intermediate-scale cavity flame stabilizer, the leading edge depth is multiplied by the coefficient 1+θ, and the trailing edge height is adjusted to follow the leading edge depth, thus obtaining a second intermediate-scale cavity flame stabilizer.

[0055] For example, let the inlet inner diameter of the second intermediate-scale concave cavity flame stabilizer be d 1-2 , the outlet inner diameter is d 2-2 , the cavity length is l2, the front edge depth is h 1-2 , the trailing edge height is h2-2 With the trailing edge inclination angle α2, the configuration parameters of the second intermediate scale cavity flame stabilizer are: 1-2 =d 1-1 d 2-2 =d 2-1 , l2=l1, α2=α1, h 1-2 =(1+θ)·h 1-1 , the trailing edge height is h 2-2 Following the leading edge depth h 1-2 Change, that is, the trailing edge height is j 2-2 The value is selected so that the bottom wall of the cavity of the second intermediate-scale cavity flame stabilizer is parallel to the axial direction of the second intermediate-scale cavity flame stabilizer.

[0056] In the specific implementation of step 4, considering the influence of fuel chemical properties, this embodiment provides a method for correcting the cavity length and trailing edge angle in three common fuels: kerosene, ethylene, and hydrogen. Specifically, the method is as follows:

[0057] If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, the second intermediate-scale concave cavity flame stabilizer is directly used as the third intermediate-scale concave cavity flame stabilizer;

[0058] If the fuel of the target-scale concave cavity flame holder is hydrogen and / or ethylene, then based on the second intermediate-scale concave cavity flame holder, the cavity length and trailing edge inclination angle are both increased by 3%-4%, while other configuration parameters remain unchanged, thus obtaining a third intermediate-scale concave cavity flame holder;

[0059] If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, ethylene and / or kerosene, then on the basis of the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are increased by 9%-10%, and the other configuration parameters remain unchanged, thus obtaining the third intermediate-scale concave cavity flame stabilizer.

[0060] For example, let the inlet inner diameter of the third intermediate-scale concave cavity flame stabilizer be d 1-3 , the outlet inner diameter is d 2-3 , the cavity length is l3, the front edge depth is h 1-3 , the trailing edge height is h 2-3 and the trailing edge inclination angle α3, the configuration parameters of the third intermediate scale cavity flame stabilizer are:

[0061] If the fuel of the target size cavity flame stabilizer is hydrogen, d 1-3 =d 1-2 d 2-3 =d 2-2 , l3=l2, α3=α2, h 1-3 =h 1-2 、h 2-3 =h2-2 ;

[0062] If the target size cavity flame stabilizer fuel is hydrogen and / or ethylene, d 1-3 =d 1-2 d 2-3 =d 2-2 , l3=(1.03~1.04)·l2, α3=(1.03~1.04)·α2, h 1-3 =h 1-2 、h 2-3 =h 2-2 ;

[0063] If the target size cavity flame stabilizer fuel is hydrogen, ethylene and / or kerosene, d 1-3 =d 1-2 d 2-3 =d 2-2 , l3=(1.09~1.1)·l2, α3=(1.09~1.1)·α2, h 1-3 =h 1-2 、h 2-3 =h 2-2 .

[0064] In the specific implementation process of step 5, the relative change of the wall heat transfer rate caused by the scale change is taken into account, so as to modify the cavity configuration. This embodiment mainly focuses on the case where the amplification coefficient n is 1 to 10. In order to maintain the relative heat transfer rate unchanged, on the basis of the third intermediate scale cavity flame stabilizer, the cavity length and the leading edge depth are multiplied by the coefficient 1-n / 50×0.81, and the trailing edge height is made to follow the leading edge depth change, so as to obtain the target scale cavity flame stabilizer.

[0065] Specifically, the one-dimensional steady flow energy equation is:

[0066]

[0067] Among them, C p is the friction coefficient, T is the temperature, x is the coordinate of any point in the flow field, h i is the total enthalpy per unit mass of component i, Y i is the mass fraction of component i, h s is the total enthalpy per unit mass of the fluid, is the fluid mass flow rate, u is the fluid velocity, h s,i,inj is the total enthalpy per unit mass of fuel, is the fuel mass flow rate, q w is the wall heat flux;

[0068] The Stanton number is defined as:

[0069]

[0070] where, p is density, Q" w is the heat flux rate of wall surface per unit area, h aw , h w are the enthalpy of adiabatic wall surface and the enthalpy of wall surface, respectively;

[0071] The relationship between the Reynolds number, Stanton number and friction coefficient C f can be expressed as:

[0072]

[0073] where, Pr is Prandtl number at reference temperature, and 0.71 is taken in the embodiment;

[0074] Combining the two expressions of Stanton number, we have:

[0075]

[0076] The enthalpy of wall surface is a function of wall surface temperature T w and adiabatic temperature T aw of wall surface, and constant pressure specific heat of main flow C m , and the constant pressure specific heat of mixed gas is C w p e , and then using the definition of wet perimeter, we have:

[0077]

[0078] where, P w is the wet perimeter, A is the cross-sectional area of the combustion chamber, and D e is the equivalent diameter;

[0079] Substituting the above formula into the differential form of one-dimensional steady flow energy equation, we have:

[0080]

[0081] The heat release per unit time is Q com = η m · m f · h f , where η m is the combustion efficiency, m f is the mass flow of fuel involved in the reaction, and h f is the reaction enthalpy of fuel; and the heat flux rate of wall surface per unit area Q" w = St· p u (h aw -h w )· A w , where A w is the wall surface per unit area; then we have:

[0082]

[0083] If St remains the same, the ratio of heat transfer / heat release remains the same, but due to in:

[0084]

[0085] Or the coefficient of friction due to the flat plate:

[0086]

[0087] Since the Reynolds coefficient Re of a small-scale combustion chamber is smaller, its friction coefficient is larger, and the heat transfer / heat release is larger. Therefore, considering the relative change of the wall heat transfer rate caused by the scale change, the cavity configuration needs to be modified. In this embodiment, multiple groups of simulation experiments are carried out before and after the combustion chamber is enlarged, and the one-dimensional steady flow energy equation in differential form is fitted according to the experimental results. It can be found that when the cavity length and the leading edge depth are multiplied by the coefficient 1-n / 50×0.81, the ratio of heat transfer / heat release can be maintained the same.

[0088] For example, if the inlet inner diameter of the target scale concave cavity flame stabilizer is df1, the outlet inner diameter is df2, the cavity length is lf, the leading edge depth is hf1, the trailing edge height is hf2 and the trailing edge inclination angle af, then the configuration parameters of the target scale concave cavity flame stabilizer are: df1 = d 1-3 、df2=d 2-3 , lf=(1-n / 50×0.81)·l3, αf=α2, hf1=(1-n / 50×0.81)·h 1-2 The trailing edge height hf2 changes with the leading edge depth hf1, that is, the trailing edge height hf2 is set so that the bottom wall of the cavity of the target scale cavity flame stabilizer is parallel to the axial direction of the cavity of the target scale flame stabilizer.

[0089] It is worth noting that the design method of the large-scale concave cavity flame stabilizer considering the scale effect in this embodiment is applicable to both the combustion chamber configuration with a rectangular cross-section and the combustion chamber configuration with a circular cross-section.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A design method for a large-scale cavity flame stabilizer considering scale effect, characterized in that: The steps include: Step 1: obtaining an amplification factor based on an inlet inner diameter of a target-scale concave cavity flame stabilizer and an inlet inner diameter of a reference small-scale concave cavity flame stabilizer; Step 2: scaling up the reference small-scale concave cavity flame stabilizer to a target scale based on the magnification factor, and correcting the cavity depth to obtain a first intermediate-scale concave cavity flame stabilizer; Step 3: Based on the first intermediate-scale concave cavity flame stabilizer, the cavity depth is corrected according to the relative thickness of the incoming flow boundary layer to obtain a second intermediate-scale concave cavity flame stabilizer; Step 4: Based on the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge angle are corrected according to the chemical properties of the fuel to obtain a third intermediate-scale concave cavity flame stabilizer; Step 5: Based on the third intermediate-scale cavity flame stabilizer, based on the wall heat transfer rate and under the premise that the cavity length-to-depth ratio remains unchanged, the cavity length, leading edge depth and trailing edge height are corrected to obtain the target-scale cavity flame stabilizer.

2. The design method of a large-scale cavity flame stabilizer considering scale effect according to claim 1 is characterized in that: Step 2 is as follows: On the basis of the benchmark small-scale concave cavity flame holder, the inlet inner diameter, the cavity length and the outlet inner diameter are linearly enlarged by n times, the leading edge depth is sublinearly enlarged by x times, and the trailing edge height is made to follow the leading edge depth while keeping the trailing edge inclination angle unchanged, thereby obtaining the first intermediate-scale concave cavity flame holder; Wherein, n is the amplification factor, and x is the sublinear amplification factor.

3. The design method of a large-scale cavity flame stabilizer considering scale effect according to claim 2 is characterized in that: The sublinear amplification factor x is specifically:

4. The method for designing a large-scale cavity flame stabilizer considering scale effect according to claim 1, 2 or 3, characterized in that: Step 3 is as follows: A relative change rate θ of the incoming flow boundary layer thickness of the first intermediate-scale concave cavity flame stabilizer is obtained based on numerical simulation or experimental observation; On the basis of the first intermediate-scale concave cavity flame stabilizer, the leading edge depth is multiplied by a coefficient 1+θ, and the trailing edge height is made to follow the change of the leading edge depth, thereby obtaining the second intermediate-scale concave cavity flame stabilizer.

5. The method for designing a large-scale cavity flame stabilizer considering scale effect according to claim 1, 2 or 3, characterized in that: Step 4 is as follows: If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, the second intermediate-scale concave cavity flame stabilizer is directly used as the third intermediate-scale concave cavity flame stabilizer; If the fuel of the target-scale concave cavity flame stabilizer is hydrogen and / or ethylene, then based on the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are increased by 3%-4%, thereby obtaining the third intermediate-scale concave cavity flame stabilizer; If the fuel of the target-scale concave cavity flame stabilizer is hydrogen, ethylene and / or kerosene, then on the basis of the second intermediate-scale concave cavity flame stabilizer, the cavity length and the trailing edge inclination angle are both increased by 9%-10%, thereby obtaining the third intermediate-scale concave cavity flame stabilizer.

6. The method for designing a large-scale cavity flame stabilizer considering scale effect according to claim 1, 2 or 3, characterized in that: Step 5 is as follows: On the basis of the third intermediate scale concave cavity flame stabilizer, the cavity length and the leading edge depth are multiplied by the coefficient 1-n / 50×0.81, and the trailing edge height is made to follow the leading edge depth, so as to obtain the target scale concave cavity flame stabilizer, wherein n is the amplification coefficient.

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