A bidirectional gradient dot matrix sandwich regenerative cooling channel and a parameterized design method thereof

Abstract

The application discloses a bidirectional gradient dot matrix sandwich regenerative cooling channel and a parameterized design method thereof, and belongs to the technical field of thermal protection of liquid rocket engines. The cooling channel comprises an outer wall, an inner wall and a dot matrix sandwich layer arranged between the outer wall and the inner wall. The dot matrix strut has a flow direction gradient along the flow direction of the cooling working medium and a normal gradient along the normal direction of the wall surface. The parameterized design method comprises the following steps: S1, constructing a normalized heat flow factor; S2, establishing a flow direction gradient strut diameter distribution; S3, determining a minimum strut diameter in a low heat flow area and checking; S4, constructing a normal gradient and determining a hot wall end diameter and a draft angle distribution; and S5, determining a cold wall end diameter and checking. The method can match the strut heat exchange capacity with the non-uniform heat flux density distribution on the gas side, and form normal gradient struts with thick hot wall ends and thin cold wall ends, so that the hot spot temperature is reduced, the temperature uniformity is improved, the pressure drop increase of the channel is controlled, and the lightweight advantage is maintained.

Description

Technical Field

[0001] This invention relates to the field of thermal protection technology for liquid rocket engines, and in particular to a bidirectional gradient lattice sandwich regenerative cooling channel and its parameterized design method. Background Technology

[0002] With the development of metal additive manufacturing technology, lattice-core regenerative cooling channels have become an important development direction for active thermal protection structures of liquid rocket engines. The rod-type lattice-core structure has advantages such as large specific surface area, strong turbulence capability, high specific stiffness, and lightweight, and can form a cooling channel between the inner and outer walls of the thrust chamber, providing both structural support and enhanced heat transfer.

[0003] In liquid rocket engines, the heat flux density on the gas side of the Laval nozzle exhibits a highly non-uniform distribution along the flow direction of the cooling medium. The throat region, in particular, typically bears the highest heat load and is the area most prone to wall hotspots and unfavorable temperatures. In the flow direction, existing lattice sandwich regenerative cooling channels often employ constant-diameter struts or constant-scale lattice unit cell designs. Their local reinforcement capabilities are difficult to match the heat flux density distribution along the flow path, easily leading to redundant reinforcement in low-heat-flux regions, unnecessary flow blockage, and material occupation. Meanwhile, the high-heat-flux region in the throat may still suffer from insufficient local reinforcement, inadequate hotspot temperature suppression, and poor wall temperature uniformity. In the wall normal direction, struts near the hot wall end directly participate in wall heat extraction and near-wall flow disturbance, which is a key mechanism for enhancing heat transfer and reducing hotspot temperatures. However, struts near the cold wall end contribute relatively little to direct heat transfer and primarily serve a structural support role. If the struts continue to use a constant-diameter or constant-scale design along the normal direction, it will not only be detrimental to improving the effective heat transfer capacity per unit material but will also occupy the cooling medium flow area and increase flow resistance.

[0004] Therefore, there is an urgent need to develop a design method for a lattice sandwich regenerative cooling channel that can redistribute materials according to the heat flux density distribution on the gas side, so as to reduce hot spot temperature, improve temperature uniformity, and at the same time take into account the requirements of channel pressure drop control and structural lightweighting. Summary of the Invention

[0005] To match the local enhancement capability of the lattice sandwich regenerative cooling channel with the non-uniform heat flux density distribution on the gas side, reduce hot spot temperature, reduce redundant material occupation and flow blockage, control the channel pressure drop increase and maintain the lightweight advantage, this invention provides a bidirectional gradient lattice sandwich regenerative cooling channel and its parameterized design method.

[0006] In a first aspect, the present invention provides a bidirectional gradient lattice sandwich regenerative cooling channel, employing the following technical solution:

[0007] A bidirectional gradient lattice sandwich regenerative cooling channel includes an outer wall, an inner wall, and a lattice sandwich layer disposed between the outer wall and the inner wall; the lattice sandwich layer is composed of multiple rod cells, each rod cell being composed of one or more support rods, and the cooling working fluid flows and exchanges heat within the cooling channel formed between the inner wall and the outer wall.

[0008] The support rod has a flow gradient along the direction of the cooling medium flow and a normal gradient along the wall normal. The flow gradient is manifested as the diameter of the hot wall end of the support rod changing with the heat flux density distribution on the gas side along the direction of the cooling medium flow. The normal gradient is manifested as the diameter of the hot wall end of the same support rod being greater than or equal to the diameter of the cold wall end, and the diameter difference between the hot wall end and the cold wall end being controlled by the local heat flux density on the gas side. The hot wall end of the support rod is the end closer to the inner wall, and the cold wall end of the support rod is the end closer to the outer wall.

[0009] Optionally, along the flow direction of the cooling working fluid, the diameter of the hot wall end of the support rod and the diameter difference between the hot wall end and the cold wall end both change continuously or change continuously in segments; at the position where the heat flux density on the gas side reaches its maximum value, the diameter of the hot wall end of the support rod reaches its maximum value in its flow direction distribution, and the diameter difference between the hot wall end and the cold wall end reaches its maximum value in its flow direction distribution.

[0010] Optionally, the strut cell is one or more combinations of body-centered cubic (BCC) cells, Kagome cells, Kelvin cells, octahedral truss cells, tetrahedral truss cells, pyramidal truss cells, and single-column cells, or topologically equivalent variants of the above cells; the cross-section of the strut is circular, elliptical, polygonal, airfoil-shaped, or equivalent variants of the above cross-sections. For non-circular cross-section struts, the strut diameter is an equivalent diameter equivalent to its cross-sectional area, or an equivalent geometric parameter characterizing its characteristic scale.

[0011] Secondly, the present invention also provides a parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel, employing the following technical solution:

[0012] A parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel, used to design the geometric parameters of the support rods in a bidirectional gradient lattice sandwich regenerative cooling channel as described in the first aspect, includes the following steps:

[0013] S1. Heat flux density distribution along the cooling medium flow direction on the gas sidewall of the regenerative cooling channel. For heat flux density distribution Normalization is performed to obtain the normalized heat flux factor distribution. ,in, The axial coordinates of the normal projection point of the lattice cell center onto the inner wall surface;

[0014] S2, Based on the normalized heat flux factor distribution and flow gradient attenuation coefficient Construct a position-dependent support diameter distribution that only considers the flow gradient. ;

[0015] S3. Based on the target equivalent support rod diameter Establish the overall equivalent volume conservation constraint during the flow gradient mapping stage, and determine the minimum support rod diameter in the low heat flux region. and to Perform a check on the minimum permissible diameter of the support rod;

[0016] S4, Distribution of support rod diameter at the location Based on the normalized heat flux factor distribution Maximum allowable draft angle of support rod and normal gradient decay coefficient Construct the draft angle distribution of the support rod and the distribution of the diameter of the position-related support rods. Location determined Distribution of hot wall end diameter of the support rod ;

[0017] S5. According to the hot wall end diameter distribution Distribution of draft angle of support rod Support rod inclination angle and channel normal height Determine the location Distribution of diameter at the cold wall end of the support rod and to The minimum allowable diameter of the support rod is verified, thereby generating the geometric parameters of the lattice support rod with flow gradient and normal gradient.

[0018] Optionally, in step S1, the normalized heat flux factor distribution The expression is:

[0019] ;

[0020] in, This represents the maximum heat flux density on the gas side. This represents the minimum heat flux density on the gas side. ,when When it approaches 1, it corresponds to a high heat flux region; when When it approaches 0, it corresponds to the region of low heat flux.

[0021] Optionally, in step S2, the position-related support rod diameter distribution The expression is:

[0022] ;

[0023] in, The maximum support rod diameter in the high heat flux region, The minimum support rod diameter in the low heat flux region; This is the flow gradient attenuation coefficient.

[0024] Optionally, in step S3, the overall equivalent volume conservation constraint is based on the target equivalent support rod diameter. The established one-dimensional continuous integral conservation model:

[0025] ;

[0026] in, As the starting point of the design area, The endpoint of the design area; This represents the axial coordinate length of the design region along the flow direction of the cooling medium. By solving the one-dimensional continuous integral conservation model, the minimum support rod diameter in the low heat flux region is determined. ;

[0027] For a lattice-core regenerative cooling channel with complex spatial curvature and discrete distribution of rod cells, the aforementioned one-dimensional continuous integral conservation model can be replaced by an incremental volume conservation model based on the physical parameters of the discrete support rods:

[0028] ;

[0029] in, This represents the total number of discrete supports generated within the design area. For the first The actual geometric length of the discrete support rod. For the first The axial coordinates of the normal projection point of the center point of the discrete support rod onto the inner wall surface are determined; by solving the cumulative volume conservation model, the minimum support rod diameter in the low heat flux region can be determined. .

[0030] Optionally, in step S4, the draft angle distribution of the support rod... The expression is:

[0031] ;

[0032] in, This is the maximum allowable draft angle of the support rod. This is the normal gradient decay coefficient.

[0033] Optionally, in step S5, the diameter distribution of the cold wall end of the support rod is... The expression is:

[0034] ;

[0035] in, The diameter distribution of the hot wall end of the support rod, For the distribution of the draft angle of the support rod, The strut inclination angle is defined as the angle between the strut axis and the normal to the wall surface. This is the channel normal height.

[0036] Optionally, in step S3, the minimum support rod diameter in the low heat flux region... satisfy: ;

[0037] in, This is the minimum permissible support rod diameter determined by structural load-bearing requirements, support rod forming stability, or additive manufacturing capabilities; if this requirement is not met, the target equivalent support rod diameter needs to be adjusted. Maximum support rod diameter in high heat flux region or flow gradient attenuation coefficient And redetermine the minimum support rod diameter in the low heat flux region. Continue until the constraints are satisfied;

[0038] In step S5, the diameter distribution of the cold wall end of the support rod is... satisfy: ;

[0039] If the requirements are not met, the maximum allowable draft angle of the support rod needs to be adjusted. Normal gradient decay coefficient Support rod inclination angle or channel normal height And redetermine the diameter distribution of the cold wall end of the support rod. Continue until the constraints are met.

[0040] In summary, the present invention has the following beneficial technical effects:

[0041] 1. This invention is driven by the non-uniform heat flux density distribution on the gas side, so that the diameter of the hot wall end of the lattice support rod adapts to the flow direction of the cooling working fluid, thereby matching the local enhanced heat transfer capacity of the lattice sandwich layer with the cooling requirements of the non-uniform heat flux density, reducing redundant enhancement in the low heat flux region and improving the targeted enhancement in the high heat flux region.

[0042] 2. This invention increases the diameter of the hot wall end of the support rod in the high heat flux region, thereby enabling the side near the hot wall to obtain stronger thermal conductivity and near-wall turbulence capability, which is beneficial to reduce the hot spot temperature in the throat and other high heat flux regions and improve the temperature uniformity along the process.

[0043] 3. By setting a normal gradient support rod with a thicker hot wall end and a thinner cold wall end, the present invention reduces the material occupation and flow blockage in the cold wall end and the low heat transfer contribution area. It can control the increase in channel pressure drop while maintaining the enhanced heat transfer capacity of the hot wall end, and is also conducive to reducing the structural mass.

[0044] 4. This invention parametrically controls the geometric distribution and shape of the lattice support rods by setting parameters such as the target equivalent support rod diameter, the maximum support rod diameter in the high heat flux zone, the minimum allowable support rod diameter, the flow gradient attenuation coefficient, the normal gradient attenuation coefficient, the maximum allowable draft angle of the support rod, the support rod inclination angle, and the channel normal height. This enables the adaptive design of the heat flux boundary of the thrust chamber or nozzle, while taking into account the structural support capacity and the feasibility of additive manufacturing. Attached Figure Description

[0045] Figure 1 A schematic diagram of the three-dimensional cross-sectional structure of a partial circumferential sector model of a bidirectional gradient lattice sandwich regenerative cooling channel provided in an embodiment of the present invention.

[0046] Figure 2 for Figure 1 A schematic diagram of the partial circumferential sector model and the shape of the rod cell at three local locations A, B, and C;

[0047] Figure 3 This is a schematic diagram of the geometric relationship of the bidirectional gradient lattice support rod in an embodiment of the present invention;

[0048] Figure 4 A schematic diagram illustrating the mapping relationship between the friction heat flux density distribution and the characteristic geometric parameters of the bidirectional gradient lattice support rod, provided in an embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram comparing the performance of a conventional equal-diameter rod lattice sandwich regeneration cooling channel with the bidirectional gradient lattice sandwich regeneration cooling channel provided in this embodiment of the invention.

[0050] Figure 6 A flowchart illustrating the parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel provided in an embodiment of the present invention.

[0051] Explanation of reference numerals in the attached drawings: 1. Outer wall; 2. Inner wall; 3. Matrix sandwich layer; 4. Gas-fired side wall; 5. Hot wall end; 6. Cold wall end. Detailed Implementation

[0052] The following is in conjunction with the appendix Figure 1-6 The present invention will be described in further detail below.

[0053] This embodiment provides a bidirectional gradient lattice sandwich regenerative cooling channel. For example... Figure 1 and Figure 2As shown, the regenerative cooling channel includes an outer wall 1, an inner wall 2, and a lattice sandwich layer 3 disposed between the outer wall 1 and the inner wall 2. The cooling medium flows within the cooling channel formed between the inner wall 2 and the outer wall 1, and absorbs the heat transferred from the gas combustion sidewall 4 through the inner wall 2 when flowing through the lattice sandwich layer 3. The lattice sandwich layer 3 is formed by multiple rod-like cells arranged alternately along the flow direction of the cooling medium.

[0054] In some alternative embodiments, the strut cell may be one or more combinations of body-centered cubic (BCC) cells, Kagome cells, Kelvin cells, octahedral truss cells, tetrahedral truss cells, pyramidal truss cells, single-strut cells, or topologically equivalent variants of the above cells; the cross-section of the strut may be circular, elliptical, polygonal, airfoilized, or equivalent variants of the above cross-sections.

[0055] In this embodiment, the support unit adopts a body-centered cubic (BCC) cell. Each support in the BCC cell has a hot wall end 5 near the inner wall 2 and a cold wall end 6 near the outer wall 1. The diameter of the hot wall end 5 of the support varies with the heat flux density distribution on the gas side along the flow direction of the cooling medium, while the diameter of the cold wall end 6 is determined by the normal gradient relationship based on the diameter of the hot wall end 5. This gives the support a flow gradient along the flow direction of the cooling medium and a normal gradient along the wall surface.

[0056] like Figure 3 and Figure 4 As shown, the diameter of the hot wall end 5 of the support rod corresponds to the heat flux density distribution on the gas side along the flow direction of the cooling working fluid, and the diameter difference between the hot wall end 5 and the cold wall end 6 is controlled by the local heat flux density on the gas side. The higher the heat flux density on the gas side, the larger the diameter of the hot wall end 5 of the support rod and the larger the diameter difference between it and the cold wall end 6; the lower the heat flux density on the gas side, the smaller the diameter of the hot wall end 5 of the support rod and the smaller or closer to zero the diameter difference between it and the cold wall end 6. Thus, the thermal conductivity and near-wall disturbance capability on the hot wall side can be enhanced in the high heat flux region, while reducing material redundancy and flow blockage in the low heat flux region.

[0057] In this embodiment, the bidirectional gradient lattice sandwich regenerative cooling channel is denoted as G-LCRCC. To verify its technical effect, a conventional equal-diameter rod BCC lattice sandwich regenerative cooling channel is set as a comparative model, denoted as LCRCC. In the comparative model, the spatial arrangement of BCC lattice cells, outer wall 1, inner wall 2, lattice sandwich layer 3, cooling channel length, cooling medium inlet conditions, outlet boundary conditions, and material parameters are all consistent with G-LCRCC. The difference is that all lattice supports in LCRCC are equal-diameter circular supports with a support diameter of 0.82mm; while in G-LCRCC, the support diameter is designed with flow gradient and normal gradient according to the parametric design method described in this invention.

[0058] This embodiment further provides a parametric design method for bidirectional gradient lattice sandwich regenerative cooling channels. For example... Figure 6 As shown, the method includes the following steps:

[0059] S1. Normalize the heat flux density distribution on the gas side to obtain the normalized heat flux factor distribution;

[0060] S2. Construct the flow gradient support rod diameter distribution;

[0061] S3. Establish the overall equivalent volume conservation constraint for the flow gradient mapping stage, solve for the minimum support rod diameter in the low heat flux region and verify it.

[0062] S4. Construct a normal gradient based on the flow gradient and determine the hot wall end diameter distribution and draft angle distribution;

[0063] S5. Determine and verify the diameter distribution of the cold wall end based on the geometric relationship of the support rods;

[0064] This method allows the enhanced heat transfer capacity of the support rod to match the non-uniform heat flux density distribution on the gas side, forming a normal gradient support rod with a thicker hot wall end and a thinner cold wall end. This reduces hot spot temperature, improves temperature uniformity, controls the increase in channel pressure drop, and maintains the advantage of lightweight design. This embodiment utilizes the non-uniform heat flux density distribution along the cooling medium flow direction on the gas side wall of the regenerative cooling channel. As the heat flux boundary input, X is the axial coordinate of the normal projection point of the lattice cell center onto the inner wall surface. In addition to the aforementioned heat flux boundary input, this embodiment provides eight parametric design and constraint parameters, namely: the maximum support rod diameter in the high heat flux region. Flow gradient attenuation coefficient Normal gradient decay coefficient Maximum allowable draft angle of support rod Target equivalent support rod diameter Minimum allowable diameter of support rod Support rod inclination angle and channel normal height .

[0065] S1. Normalize the heat flux density distribution on the gas side to obtain the normalized heat flux factor distribution.

[0066] like Figure 4 As shown, in this embodiment, the heat flux density distribution on the gas side... The design area is: Maximum heat flux density Minimum heat flux density Heat flux density distribution on the gas side Normalization is performed to obtain the normalized heat flux factor distribution. :

[0067] ;

[0068] in, ,when When it approaches 1, it corresponds to a high heat flux region; when When the value approaches 0, it corresponds to a low heat flux region. Therefore, the non-uniform heat flux density on the gas side is transformed into a dimensionless heat flux factor capable of driving geometric changes in the lattice struts.

[0069] S2. Construct the flow gradient support rod diameter distribution.

[0070] Based on normalized heat flux factor distribution Establish position-dependent support rod diameter distribution , Location when only the flow gradient is considered Diameter of the support rod at the location:

[0071] ;

[0072] At this point, the diameter of the flow gradient support rod is... The solution still needs to be based on Determine the minimum support rod diameter in the low heat flux region .

[0073] S3. Establish the overall equivalent volume conservation constraint for the flow gradient mapping stage, solve for the minimum support rod diameter in the low heat flux region and verify it.

[0074] To strengthen the support rod in the high heat flux region while controlling the equivalent size of the support rod during the flow direction gradient mapping stage, this embodiment is based on the target equivalent support rod diameter. Establish the overall equivalent volume conservation constraint for the flow gradient mapping stage:

[0075] ;

[0076] in, As the starting point of the design area, The endpoint of the design area; This represents the axial coordinate length of the design region along the flow direction of the cooling medium. By solving the one-dimensional continuous integral conservation model, the minimum support rod diameter in the low heat flux region is determined. ;

[0077] Substituting the known parameters in this embodiment, the solution is obtained. In this embodiment, the minimum permissible support rod diameter is taken as: ,because Therefore, the minimum support rod diameter in the low heat flux region obtained from the flow gradient design satisfies the minimum allowable support rod diameter constraint. If it does not, the target equivalent support rod diameter needs to be adjusted. Maximum support rod diameter in high heat flux region Alternatively, determine the flow gradient attenuation coefficient n, and redetermine the minimum support diameter in the low heat flux region. .

[0078] Will Substitute into S2 The expression can be used to solve for the global flow direction gradient support diameter distribution. .

[0079] For a lattice-core regenerative cooling channel with complex spatial curvature and discrete distribution of rod cells, the aforementioned one-dimensional continuous integral conservation model can be replaced by an incremental volume conservation model based on the physical parameters of the discrete support rods:

[0080] ;

[0081] in, This represents the total number of discrete supports generated within the design area. For the first The actual geometric length of the discrete support rod. For the first The axial coordinates of the normal projection point of the center point of the discrete support rod onto the inner wall surface are determined; by solving the cumulative volume conservation model, the minimum support rod diameter in the low heat flux region can be determined. .

[0082] S4. Construct a normal gradient based on the flow gradient and determine the hot wall end diameter distribution and draft angle distribution.

[0083] Obtain the distribution of support rod diameters related to the flow direction. Afterwards, Location determined Diameter distribution of the hot wall end of the support rod at the location ,Right now Distribution of draft angles of support rods From the normalized heat flux factor distribution control:

[0084] ;

[0085] In this embodiment, , The draft angle distribution of the support rod can be solved by substituting the values. .when At that time, the draft angle distribution of the support rod reaches its maximum value: ;when At that time, the draft angle distribution of the support rod Therefore, the normal gradient of the strut is mainly concentrated in the high heat flux region of the throat, and gradually weakens or returns to a strut of equal diameter in the low heat flux region.

[0086] S5. Determine and verify the diameter distribution of the cold wall end based on the geometric relationship of the support rod.

[0087] Based on the distribution of hot wall end diameters Distribution of draft angle of support rod Support rod inclination angle and channel normal height Determine the location Distribution of cold wall end diameters of support rods at the location :

[0088] ;

[0089] In this embodiment, the support rod tilt angle Channel normal height The diameter distribution at the cold wall end of the support rod can be solved by substituting the values. .

[0090] After verification, the minimum diameter of the cold wall end in this embodiment is... .because Therefore, the normal gradient design satisfies the minimum allowable diameter constraint of the support rod.

[0091] If the requirements are not met, the maximum allowable draft angle of the support rod needs to be adjusted. Normal gradient attenuation coefficient m, support rod inclination angle or channel normal height And redetermine the minimum diameter of the cold wall end of the support rod. Continue until the constraints are met.

[0092] In this embodiment, under the given conditions of cooling medium inlet conditions, outlet boundary conditions, material parameters, and non-uniform heat flux density on the gas side, Fluent conjugate heat transfer calculations are used to compare the key performance characteristics of G-LCRCC and conventional constant-diameter rod LCRCC. Figure 5 As shown, compared to conventional LCRCC with a constant diameter rod, the hot spot temperature of G-LCRCC is reduced by 64.34 K, a decrease of 7.12%; the structural mass is reduced by 0.53 g, a decrease of 2.27%; and the channel pressure drop increases by 0.29 MPa, an increase of 5.72%. Therefore, under the operating conditions of this embodiment, the bidirectional gradient lattice sandwich regenerative cooling channel of the present invention can significantly enhance the local cooling capacity of high heat flux regions, reduce hot spot temperatures, and while maintaining the advantage of lightweight structure, control the increase in pressure drop within a small range.

[0093] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel, characterized in that: Includes the following steps: S1. Heat flux density distribution along the cooling medium flow direction on the gas sidewall of the regenerative cooling channel. For heat flux density distribution Normalization is performed to obtain the normalized heat flux factor distribution. ,in, The axial coordinates of the normal projection point of the lattice cell center onto the inner wall surface; S2, Based on the normalized heat flux factor distribution and flow gradient attenuation coefficient Construct a position-dependent support diameter distribution that only considers the flow gradient. ; S3. Based on the target equivalent support rod diameter Establish the overall equivalent volume conservation constraint during the flow gradient mapping stage, and determine the minimum support rod diameter in the low heat flux region. and to Perform a check on the minimum permissible diameter of the support rod; S4, Distribution of support rod diameter at the location Based on the normalized heat flux factor distribution Maximum allowable draft angle of support rod and normal gradient decay coefficient Construct the draft angle distribution of the support rod and the distribution of the diameter of the position-related support rods. Location determined Distribution of hot wall end diameter of the support rod ; S5. According to the hot wall end diameter distribution Distribution of draft angle of support rod Support rod inclination angle and channel normal height Determine the location Distribution of diameter at the cold wall end of the support rod and to The minimum allowable diameter of the support rod is verified, thereby generating the geometric parameters of the lattice support rod with flow gradient and normal gradient.

2. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 1, characterized in that: In step S1, the normalized heat flux factor distribution The expression is: ； in, This represents the maximum heat flux density on the gas side. This represents the minimum heat flux density on the gas side. ,when When it approaches 1, it corresponds to a high heat flux region; when When it approaches 0, it corresponds to the region of low heat flux.

3. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 2, characterized in that: In step S2, the diameter distribution of the position-related support rods... The expression is: ； in, The maximum support rod diameter in the high heat flux region, The minimum support rod diameter in the low heat flux region; The flow gradient attenuation coefficient is used to control the rate at which the diameter of the support rod decreases along the flow direction from the high heat flux region to the low heat flux region.

4. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 3, characterized in that: In step S3, the overall equivalent volume conservation constraint is based on the target equivalent support rod diameter. The established one-dimensional continuous integral conservation model: ； in, As the starting point of the design area, The endpoint of the design area; This represents the axial coordinate length of the design region along the flow direction of the cooling medium. By solving the one-dimensional continuous integral conservation model, the minimum support rod diameter in the low heat flux region is determined. ; For a lattice-core regenerative cooling channel with complex spatial curvature and discrete distribution of rod cells, the aforementioned one-dimensional continuous integral conservation model can be replaced by an incremental volume conservation model based on the physical parameters of the discrete support rods: ； in, This represents the total number of discrete supports generated within the design area. For the first The actual geometric length of the discrete support rod. For the first The axial coordinates of the normal projection point of the center point of the discrete support rod onto the inner wall surface are determined; by solving the cumulative volume conservation model, the minimum support rod diameter in the low heat flux region can be determined. .

5. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 4, characterized in that: In step S4, the draft angle distribution of the support rod is determined. The expression is: ； in, This is the maximum allowable draft angle of the support rod. This is the normal gradient decay coefficient.

6. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 5, characterized in that: In step S5, the diameter distribution of the cold wall end of the support rod is... The expression is: ； in, The diameter distribution of the hot wall end of the support rod, For the distribution of the draft angle of the support rod, The strut inclination angle is defined as the angle between the strut axis and the normal to the wall surface. This is the channel normal height.

7. The parametric design method for a bidirectional gradient lattice sandwich regenerative cooling channel according to claim 6, characterized in that: In step S3, the minimum support rod diameter in the low heat flux region satisfies: ; in, This is the minimum permissible support rod diameter determined by structural load-bearing requirements, support rod forming stability, or additive manufacturing capabilities; if this requirement is not met, the target equivalent support rod diameter needs to be adjusted. Maximum support rod diameter in high heat flux region or flow gradient attenuation coefficient And redetermine the minimum support rod diameter in the low heat flux region. Continue until the constraints are satisfied; In step S5, the diameter distribution of the cold wall end of the support rod is... satisfy: ; If the requirements are not met, the maximum allowable draft angle of the support rod needs to be adjusted. Normal gradient decay coefficient Support rod inclination angle or channel normal height And redetermine the diameter distribution of the cold wall end of the support rod. Continue until the constraints are met.

8. A bidirectional gradient lattice sandwich regenerative cooling channel, obtained by the parametric design method of the bidirectional gradient lattice sandwich regenerative cooling channel as described in claim 7; it includes an outer wall, an inner wall, and a lattice sandwich layer disposed between the outer wall and the inner wall; the lattice sandwich layer is composed of multiple rod cells, each rod cell being composed of one or more support rods, and the cooling medium flows and exchanges heat within the cooling channel formed between the inner wall and the outer wall; characterized in that: The support rod has a flow gradient along the direction of the cooling medium flow and a normal gradient along the wall normal. The flow gradient is manifested as the diameter of the hot wall end of the support rod changing with the heat flux density distribution on the gas side along the direction of the cooling medium flow. The normal gradient is manifested as the diameter of the hot wall end of the same support rod being greater than or equal to the diameter of the cold wall end, and the diameter difference between the hot wall end and the cold wall end being controlled by the local heat flux density on the gas side. The hot wall end of the support rod is the end closer to the inner wall, and the cold wall end of the support rod is the end closer to the outer wall.

9. A bidirectional gradient lattice sandwich regenerative cooling channel according to claim 8, characterized in that: Along the flow direction of the cooling working fluid, the diameter of the hot wall end of the support rod and the diameter difference between the hot wall end and the cold wall end both change continuously or change continuously in segments; at the position where the heat flux density on the gas side reaches its maximum value, the diameter of the hot wall end of the support rod reaches its maximum value in its flow direction distribution, and the diameter difference between the hot wall end and the cold wall end reaches its maximum value in its flow direction distribution.

10. A bidirectional gradient lattice sandwich regenerative cooling channel according to claim 8, characterized in that: The truss cell is one or more combinations of body-centered cubic (BCC) cells, Kagome cells, Kelvin cells, octahedral truss cells, tetrahedral truss cells, pyramidal truss cells, and single-support cells, or topologically equivalent variants of the above cells; the cross-section of the support is circular, elliptical, polygonal, airfoilized, or equivalent variants of the above cross-sections; for non-circular cross-section supports, the support diameter is an equivalent diameter equivalent to its cross-sectional area, or an equivalent geometric parameter characterizing its characteristic scale.

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