Method for screening of binders for binder jet additive manufacturing of solid propellant binders
Patent Information
- Application Number
- CN202610951033.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-29
- Publication Date
- 2026-10-30
AI Technical Summary
传统实验研究方法周期长、成本高、效率有限
1）本发明通过构建三维粉末床模型并结合液滴喷射过程的数值仿真，实现了对黏合剂液滴铺展与浸润行为的定量表征，避免了传统试错法对大量物理实验的依赖，显著缩短了黏合剂的筛选与研发周期。
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Figure CN123017279A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid propellant additive manufacturing technology, and in particular, it is a method for screening binders for solid propellant additive manufacturing with binder spraying. Background Technology
[0002] Binder jetting technology, as a common additive manufacturing technique, boasts advantages such as high printing efficiency, no heat source input, and flexible geometry, making it a promising application in the field of solid propellants. Currently, there is still considerable room for research and development regarding the binders used in binder jetting additive manufacturing of solid propellants. Traditional experimental research methods are time-consuming, costly, and have limited efficiency. Summary of the Invention
[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a screening method for solid propellant binders in binder-jetting additive manufacturing, which saves experimental costs and shortens the research and development cycle.
[0004] The technical solution of this invention is: Screening methods for solid propellant binders in binder-jet additive manufacturing include: 1) Particle size analysis experiments were conducted on AP powder raw materials and Al powder raw materials in solid propellants to obtain the diameter of AP powder and Al powder respectively; 2) The diameter of AP powder obtained in step 1) is equivalent to the diameter of a first-order sphere, and the diameter of Al powder obtained in step 1) is equivalent to the diameter of a second-order sphere. Based on Horsfield's packing theory, a three-dimensional powder bed model is established. 3) Using the three-dimensional powder bed model obtained in step 2), the spreading and wetting process of adhesive droplets of different components on the powder bed is simulated and calculated to obtain the quantitative parameters of the spreading and wetting process of adhesive droplets. 4) The quantitative parameters of the spreading and wetting process are obtained from step 3), and the qualitative indicators for screening adhesive droplets of different components are determined. 5) Using the qualitative indicators of adhesive droplets obtained in step 4), draw a scatter plot of adhesive droplets with different component ratios; 6) From the scatter plot, select the adhesive component with the qualitative index of the adhesive droplet screening that is closest to 1 as the optimal adhesive formulation, which will be used as the adhesive for jet manufacturing of solid propellants.
[0005] Preferably, the method for establishing the three-dimensional powder bed model in step 2) is as follows: AP powder is equivalent to a regular octahedron formed by hexagonal close packing of first-order spheres, and Al powder is equivalent to filling the voids of the regular octahedron formed by first-order spheres with second-order spheres, thus obtaining a three-dimensional powder bed model.
[0006] Preferably, the quantification parameter includes: adhesive droplet spreading area. The wetting depth of adhesive droplets Unwetting depth of adhesive droplets .
[0007] Preferably, among the qualitative indicators, Powder coverage; This refers to the relative depth of penetration.
[0008] Preferably, powder coverage The calculation method is as follows:
[0009]
[0010] in, The equivalent area of the sphere covered by the adhesive droplets. Let the radius of the sphere be a first-order sphere. The number of times the adhesive droplets cover the sphere once.
[0011] Preferably, relative immersion depth The calculation method is as follows:
[0013] Preferably, the adhesive is composed of n-hexane, HTPBⅢ, DOS and IPDI; The mass ratio range of the different component adhesives mentioned in step 3) is as follows: The mass ratio of n-hexane is no more than 70%, the mass ratio of HTPBⅢ is no more than 50%, and the mass ratio of DOS and IPDI is 10%.
[0014] Preferably, the adhesive is composed of n-hexane, HTPBⅢ, DOS and TDI; The mass ratio range of the different component adhesives mentioned in step 3) is as follows: The mass ratio of n-hexane is no more than 70%, the mass ratio of HTPBⅢ is no more than 50%, and the sum of the mass ratios of DOS and TDI is 10%.
[0015] The advantages of this invention compared to the prior art are: 1) This invention achieves quantitative characterization of adhesive droplet spreading and wetting behavior by constructing a three-dimensional powder bed model and combining it with numerical simulation of the droplet jetting process. This avoids the reliance on a large number of physical experiments in the traditional trial-and-error method and significantly shortens the screening and development cycle of adhesives.
[0016] 2) This invention uses computational simulation to replace experimental exploration, which greatly reduces the consumption of solid propellant raw materials (AP, Al powder) and binder samples, reduces the safety risks and raw material costs of pyrotechnics testing, and thus significantly reduces the cost of research and development testing.
[0017] 3) This invention establishes evaluation indicators and performs visualization analysis by drawing scatter plots, forming a systematic rapid screening mechanism for binders. It provides an efficient and quantifiable new approach for the design of binder systems for solid propellants in binder spray additive manufacturing, overcoming the problems of strong subjectivity and poor universality of existing experience-based screening methods. Attached Figure Description
[0018] Figure 1 This is a flowchart of the method of the present invention.
[0019] Figure 2 To simplify the construction of a three-dimensional powder bed model for solid propellants.
[0020] Figure 3 The values represent the droplet spreading area and the wetting and unwetting depths of the droplet at 5 ms. Detailed Implementation
[0021] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.
[0022] like Figure 1 As shown, this invention proposes a screening method for binders in solid propellant additive manufacturing using binder spraying, comprising the following four parts: Based on experimental results of particle size analysis of ammonium perchlorate (AP) and aluminum powder (Al) in solid propellants, a simplified three-dimensional powder bed model of the solid propellant is constructed; based on the powder bed model, the spreading and wetting process of binder droplets on the powder bed is simulated and calculated to obtain quantitative parameters of binder droplet spreading and penetration under different component ratios; and a quantifiable evaluation index, namely powder coverage, is determined. and relative infiltration depth ; Draw scatter plots of the penetration of different adhesives to screen for the optimal adhesive formulation. Specifically, this includes the following steps: 1) Particle size analysis experiments were conducted on AP powder raw materials and Al powder raw materials in solid propellant. The diameter of AP powder was used as the diameter of a first-order sphere, and the diameter of Al powder was used as the diameter of a second-order sphere. Based on Horsfield's packing theory, a simplified three-dimensional powder bed model was obtained. AP powder raw material is used as primary spheres in a hexagonal close-packed manner to form a powder bed base; secondary spheres are then filled into the octahedral voids formed by the primary spheres to obtain, as shown below. Figure 2 The three-dimensional powder bed model shown.
[0023] In this embodiment of the invention, the AP powder raw material is set to have a diameter of 100 micrometers, and the Al powder raw material is set to have a diameter of 41.4 micrometers.
[0024] 2) Based on the three-dimensional powder bed model obtained in step 1), the spreading and wetting process of adhesive droplets on the powder bed is simulated and calculated to obtain quantitative parameters of the spreading and wetting process of adhesive droplets within 5ms; the quantitative parameters include: the spreading area of adhesive droplets. The depth of droplet wetting With unwetting depth Unwetting depth Characterizes the maximum height from the upper surface of the droplet that has not penetrated into the particle to the surface of the three-dimensional powder bed model.
[0025] Specifically: 21) After extracting the fluid domain from the three-dimensional powder bed model, import it into the computational fluid dynamics simulation software. Set a spherical droplet with a diameter of 100 micrometers to fall at a speed of 1 m / s at an initial height of 10 micrometers above the powder bed. The computational fluid dynamics simulation software includes, but is not limited to, ANSYS, STAR-CCM+, OpenFOAM, and COMOSL.
[0026] 22) The spreading and wetting process of binder droplets on the powder bed in the process of binder jet additive manufacturing of solid propellants was simulated. The contact angle, surface tension and viscosity of spherical droplets on the powder bed surface were adjusted according to the properties of different binder components (see Table 1). The calculation was repeated until convergence to obtain the quantitative parameters of the spreading and wetting process of different binders on the powder bed.
[0027] 3) Quantitative parameters of the spreading and wetting process are obtained from step 2), thereby determining the qualitative indicators for adhesive droplet screening. These evaluation indicators are quantitative indicators, specifically including: Powder coverage
[0028]
[0029] in, The spread area of the adhesive droplets on the powder bed, in units of ; The equivalent area of the sphere covered by the adhesive droplet is expressed in units of... The calculation formula is:
[0030] In the formula, Let the radius of the sphere be a first-order sphere. The number of times the adhesive droplets cover the sphere once. .
[0031] Relative depth of penetration
[0032]
[0033] in, The depth to which the adhesive droplets penetrate the powder bed, measured in units of... ; The depth to which the adhesive droplets are not wetted in the powder bed, in units of .
[0034] 4) Based on powder coverage The x-axis represents the relative wetting depth. Plot a scatter plot of adhesive droplets with different component ratios, using the vertical axis as the ordinate. Value and The closer the values are to 1, meaning the scatter points corresponding to the adhesive are located in the upper right region of the scatter plot, the more suitable the adhesive is for the manufacturing of binders for solid propellants.
[0035] Example The 3D model of the powder bed was imported into SpaceClaim as an STL file. Interfaces were merged, sharp corners and details were processed, and the fluid domain was extracted. Using Mesh software, the fluid domain was divided into tetrahedral and hexahedral meshes. The generated mesh file was then imported into the Setup module of Fluent for solution calculation. Boundary conditions were set as fixed walls around the powder bed and at the bottom, with the powder surface set as a fixed no-slip wall boundary. The top was set as a pressure outlet boundary condition with an outlet pressure of 0. A 100 μm diameter spherical adhesive droplet was initially introduced into the powder bed at a position 10 μm above the bed with an initial velocity of 1 m / s. A pressure-based solver using the VOF model was employed. The pressure field was estimated by solving the nonlinear Poisson equation, and then correction terms were iteratively applied to the pressure gradient term until the velocity solution converged to the continuity equation.
[0036] A series of hydroxyl-terminated polybutadiene adhesive systems with different ratios were set up as shown in Table 1. The spreading and wetting process was simulated and calculated. The contact angle, surface tension and viscosity of the spherical adhesive droplets and the powder bed were changed. The calculation was performed until convergence. The spreading area of the droplets, as well as the wetting depth and non-wetting depth of the droplets were recorded at 5ms for different adhesives.
[0037] Table 1. Values for contact angle, surface tension, and viscosity for adhesives with different components.
[0038] The grouping principles for adhesives with different components are as follows: For adhesives composed of hexane, HTPBⅢ, DOS, and IPDI, the mass ratio of hexane shall not exceed 70%, the mass ratio of HTPBⅢ shall not exceed 50%, and the mass ratio of DOS and IPDI shall be 10%.
[0039] For adhesives composed of hexane, HTPBⅢ, DOS, and TDI, the mass ratio of hexane should not exceed 70%, the mass ratio of HTPBⅢ should not exceed 50%, and the mass ratio of DOS and TDI should be 10%.
[0040] The diluent in the adhesive is n-hexane, the adhesive is HTPBⅢ (hydroxyl-terminated polybutadiene), the plasticizer is diisooctyl sebacate (DOS), and the curing agent is isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI).
[0041] Taking an adhesive system of 60 wt.% hexane, 30 wt.% HTPBⅢ, 6 wt.% DOS, and 4 wt.% IPDI as an example, the surface tension of the spherical adhesive droplets is set to 0.0285 N / m and the viscosity to be 1.2 × 10⁻⁶ N / m. -5 kg / s·m, contact angle with powder bed is 30° The simulation yielded the adhesive droplet spreading area at 5 ms, as well as the wetting depth and unwetting depth of the droplets. Figure 3 As shown. The droplet spreading area was measured using ImageJ. The value is 31375.26. It covers a total of 5 spherical particles. The value is 39349.17 . , It is 93.12 μm. The value is 30.4 μm. Calculations show that K1 is 0.80 and K2 is 0.75.
[0042] Calculate the K values for different formulations in sequence, and plot a scatter plot with K1 as the x-axis and K2 as the y-axis.
[0043] The results showed that the droplets completely penetrated within 4 ms, with a spreading diameter of 417 μm and a penetration depth of 143 μm; the calculated adhesive saturation was 30.9%. The above process was repeated to obtain simulation results for different hydroxyl-terminated polybutadiene adhesive systems. A scatter plot of adhesive droplets with different component ratios was plotted with powder coverage on the x-axis and relative wetting depth on the y-axis. Adhesive number 4 had the highest k-value, therefore adhesive number 4 is most suitable for the jet manufacturing of binders for solid propellants.
[0044] This invention utilizes numerical simulation to establish a rapid screening mechanism for binders in binder-jet additive manufacturing of solid propellants, significantly shortening the R&D cycle and reducing testing costs. It provides an efficient and feasible new approach for the design of binder systems for binder-jet additive manufacturing of solid propellants.
[0045] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. Where there is no conflict, the embodiments of this application and the technical features thereof can be combined with each other.
[0046] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A method for screening binders for solid propellant adhesives in binder-jet additive manufacturing, characterized in that, include: 1) Particle size analysis experiments were conducted on AP powder raw materials and Al powder raw materials in solid propellants to obtain the diameter of AP powder and Al powder respectively; 2) The diameter of AP powder obtained in step 1) is equivalent to the diameter of a first-order sphere, and the diameter of Al powder obtained in step 1) is equivalent to the diameter of a second-order sphere. Based on Horsfield's packing theory, a three-dimensional powder bed model is established. 3) Using the three-dimensional powder bed model obtained in step 2), the spreading and wetting process of adhesive droplets of different components on the powder bed is simulated and calculated to obtain the quantitative parameters of the spreading and wetting process of adhesive droplets. 4) The quantitative parameters of the spreading and wetting process are obtained from step 3), and the qualitative indicators for screening adhesive droplets of different components are determined. 5) Using the qualitative indicators of adhesive droplets obtained in step 4), draw a scatter plot of adhesive droplets with different component ratios; 6) From the scatter plot, select the adhesive component with the qualitative index of the adhesive droplet screening that is closest to 1 as the optimal adhesive formulation, which will be used as the adhesive for jet manufacturing of solid propellants.
2. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 1, characterized in that, The method for establishing the three-dimensional powder bed model in step 2) is as follows: AP powder is equivalent to a regular octahedron formed by hexagonal close packing of first-order spheres, and Al powder is equivalent to filling the voids of the regular octahedron formed by first-order spheres with second-order spheres, thus obtaining a three-dimensional powder bed model.
3. The method for screening solid propellant binders for binder-oriented additive manufacturing according to any one of claims 1-2, characterized in that, The quantitative parameters include: adhesive droplet spreading area. The wetting depth of adhesive droplets Unwetting depth of adhesive droplets .
4. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 3, characterized in that, Among the qualitative indicators, Powder coverage; This refers to the relative depth of penetration.
5. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 4, characterized in that, Powder coverage The calculation method is as follows: in, The equivalent area of the sphere covered by the adhesive droplets. Let the radius of the sphere be a first-order sphere. The number of times the adhesive droplets cover the sphere once.
6. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 5, characterized in that, Relative depth of penetration The calculation method is as follows: 。 7. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 6, characterized in that, The adhesive consists of n-hexane, HTPBⅢ, DOS, and IPDI; The mass ratio range of the different component adhesives mentioned in step 3) is as follows: The mass ratio of n-hexane is no more than 70%, the mass ratio of HTPBⅢ is no more than 50%, and the mass ratio of DOS and IPDI is 10%.
8. The screening method for solid propellant binders in binder-jet additive manufacturing according to claim 6, characterized in that, The adhesive consists of n-hexane, HTPBⅢ, DOS, and TDI; The mass ratio range of the different component adhesives mentioned in step 3) is as follows: The mass ratio of n-hexane is no more than 70%, the mass ratio of HTPBⅢ is no more than 50%, and the sum of the mass ratios of DOS and TDI is 10%.