A carrier liner design method based on thermal expansion difference
The thermal expansion difference value is calculated and the thickness of the gasket is reverse solved through the finite element algorithm, and the amount of vermiculite is accurately controlled, which solves the problem that the vermiculite addition ratio in the gasket design in the existing technology is difficult to accurately control, and improves the sealing property of the catalyst and thermal insulation properties.
Patent Information
- Application Number
- CN202111206589.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-10-17
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2041-10-17
AI Technical Summary
The existing gasket design is difficult to accurately control the vermiculite addition ratio, resulting in insufficient or excessive packaging pressure, affecting the sealing and thermal insulation performance of the catalyst.
The thermal expansion difference between the catalyst carrier and the shell is calculated by finite element algorithm, the gasket expansion thickness and vermiculite addition amount are solved in reverse, the expansion multiple and mass of vermiculite particles are accurately controlled, and the gasket material ratio is optimized.
Accurate control of the proportion of carrier micro-expanded gasket material is achieved, the content of vermiculite particles is reduced, the insulation effect is improved, and the problem of excessive or low packaging pressure is avoided.
Smart Images
Figure CN114021402B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of liner design, and in particular to a carrier liner design method based on thermal expansion difference. Background Art
[0002] The gasket is an important component of the post-treatment catalyst. When the catalyst is packaged, the gasket can be used to fix and support the carrier to prevent it from being damaged, and it also plays a role in sealing and heat insulation. Existing gasket products can basically be divided into two types: expansion type and non-expansion type. The expansion gasket containing vermiculite can use the irreversible expansion of vermiculite itself when heated to achieve the packaging pressure required by the post-treatment catalyst. The packaging pressure has a vital influence on the catalyst: if the packaging pressure is too low, it is easy to cause serious problems such as air leakage and carrier displacement; if the packaging pressure is too high, it is easy to cause the thin-walled carrier to rupture, be damaged and lose its function; and if the proportion of vermiculite added is too high, it will also cause the gasket's high temperature resistance and thermal insulation capabilities to be seriously reduced. In the current process, the proportion of vermiculite added is often obtained through experience or finished product testing, and it is impossible to carry out precise and scientific design according to the actual post-treatment situation. Summary of the invention
[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a carrier liner design method based on thermal expansion difference which can accurately control the proportion of slurry and vermiculite.
[0004] To achieve the above object, the present invention provides a carrier liner design method based on thermal expansion difference, comprising the following steps:
[0005] S1: By inputting the shape parameters and material property parameters of the carrier and the shell, the FEM finite element algorithm is used to obtain the thermal expansion difference between the carrier and the catalyst shell at the common temperature of the catalyst. The actual use gap is the thermal expansion difference plus the initial geometric gap;
[0006] S2: Input the required carrier packaging pressure P, and use the finite element algorithm to reversely solve the liner expansion thickness and the volume difference V' that needs to be filled in the gap;
[0007] S3: Calculate the average expansion multiple K of the vermiculite particles at a constant temperature using the liner expansion thickness, the vermiculite thermal expansion coefficient α and the average diameter d;
[0008] S4: Determine the proportion of vermiculite added according to the volume V of vermiculite added;
[0009] S5: Calculate the added mass m of the vermiculite in this batch according to the average volume density ρ of the vermiculite.
[0010] Furthermore, the finite element algorithm solves the gap volume difference after expansion to be V':
[0011] V'=[(R2+S2)2 +(R1+S1) 2 -R2 2 +R1 2 ]πL
[0012] S1 is the average radial displacement of the carrier at a specific temperature, S2 is the average radial displacement of the metal shell, R1 is the radius of the carrier, R2 is the radius of the metal shell, L is the axial length of the carrier, and there is an initial filling gap R2-R1 and a gap volume (R2 2 -R1 2 )πL,
[0013] The expansion multiple of vermiculite is K, and the average volume density is ρ, then the vermiculite mass m is obtained:
[0014]
[0015] The present invention can calculate the thermal expansion difference between the catalyst shell and the carrier at high temperature through the initial catalyst shell and carrier material properties, shape and other parameters, with the aim of accurately controlling the raw material ratio in the carrier micro-expansion liner and minimizing the content of vermiculite particles, thereby achieving the optimal thermal insulation and heat preservation packaging effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of a carrier liner design method based on thermal expansion difference;
[0017] Figure 2 This is an example of the thermal expansion difference between the carrier and the metal shell using the finite element method. DETAILED DESCRIPTION
[0018] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the following embodiments are merely illustrative in nature, and the present invention is not intended to limit its applicable objects or uses, and the present invention is not limited to the following embodiments.
[0019] like Figure 1 As shown, a carrier liner design method based on thermal expansion difference includes the following steps:
[0020] S1: By inputting the shape parameters and material property parameters of the carrier and the shell, the FEM finite element algorithm is used to obtain the thermal expansion difference between the carrier and the catalyst shell at the common temperature of the catalyst. The actual use gap is the thermal expansion difference plus the initial geometric gap;
[0021] S2: Input the required carrier packaging pressure P, and use the finite element algorithm to reversely solve the liner expansion thickness and the volume difference V' that needs to be filled in the gap;
[0022] S3: Calculate the average expansion multiple K of the vermiculite particles at a constant temperature using the liner expansion thickness, the vermiculite thermal expansion coefficient α and the average diameter d;
[0023] S4: Determine the proportion of vermiculite added according to the volume V of vermiculite added;
[0024] S5: Calculate the added mass m of the vermiculite in this batch according to the average volume density ρ of the vermiculite.
[0025] The finite element thermal expansion algorithm is as follows: This method requires the known mechanical, thermal properties and shape parameters of the calculation target. For example, the geometric deformations of the carrier and the catalyst shell can be obtained separately based on the finite element thermal expansion algorithm.
[0026] ε x =ε y =ε z =α·T
[0027] Where ε is the thermal strain; α is the linear thermal expansion coefficient of the material, which can be determined by experiment; T is the difference between the maximum temperature and the normal temperature of the catalyst;
[0028] {ε0}=[αT aT aT 0 0 0] T
[0029] ε0 is regarded as the initial thermal strain. According to the principle of thermal expansion, the work done by the external force is W a is zero, the internal force does work W i Equal to the work done by external force:
[0030] δW i =∫ Ω {σ}·δ{ε}dΩ
[0031] g=δW i -δW a =0
[0032] δW i =∫ Ω {σ}·δ{ε}dΩ=0
[0033] Where σ is the thermal stress under thermal strain, combined with the initial thermal strain ε0:
[0034] {σ}=[D]·({ε}-{ε0})=[D]·{ε}-[D]·{ε0}
[0035] Where D is the performance parameter characterization, [D] is the elastic matrix, according to the FEM finite element algorithm, combined with the geometric shape, there is:
[0036] δ{ε} e =[B] e ·δ[q] e
[0037]
[0038] B is the geometric representation, [B] is the geometric matrix, [q] is the displacement matrix, and the work done according to the unit is zero;
[0039]
[0040]
[0041] Introducing the element stiffness matrix [K] e and the initial load matrix [P0] e :
[0042]
[0043]
[0044] The total system load matrix [P] can be obtained:
[0045] [K] e [q] e =[P] e →[K][q]=[P]
[0046] [q]=[u1 v1 w1 ... u n v n w n ] T
[0047] The set of equations can be solved to obtain the displacement [u, v, w] under the three-dimensional thermal expansion of the target space, thereby calculating the target thermal expansion.
[0048] Preferably, the finite element algorithm solves the gap volume difference after expansion to be V':
[0049] V'=[(R2+S2) 2 +(R1+S1) 2 -R2 2 +R1 2 ]πL
[0050] S1 is the average radial displacement of the carrier at a specific temperature, S2 is the average radial displacement of the metal shell, R1 is the radius of the carrier, R2 is the radius of the metal shell, L is the axial length of the carrier, and there is an initial filling gap R2-R1 and a gap volume (R2 2 -R1 2 )πL,
[0051] The expansion multiple of vermiculite is K, and the average volume density is ρ, then the vermiculite mass m is obtained:
[0052]
[0053] Actual example: Figure 2 As shown, the carrier radius R1 is 100 mm, the metal shell radius R2 is 105 mm, the initial gap is 5 mm, and the average radial displacement S2 is 0.873 mm and S1 is 0.115 mm after finite element algorithm simulation calculation;
[0054] Assuming that the expansion multiple of vermiculite K = 10, the mass of vermiculite added in this batch can be obtained by approximate calculation according to the formula: m = 14.2ρ; where ρ is the average volume density of vermiculite.
[0055] The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments can also be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the technical concept of the present invention.
Claims
1. A carrier liner design method based on thermal expansion difference, characterized in that: The following steps are involved: S1: By inputting the shape parameters and material property parameters of the carrier and the shell, the FEM finite element algorithm is used to obtain the thermal expansion difference between the carrier and the catalyst shell at the common temperature of the catalyst. The actual use gap is the thermal expansion difference plus the initial geometric gap; S2: Input the required carrier packaging pressure P, and use the finite element algorithm to reversely solve the liner expansion thickness and the volume difference V' that needs to be filled in the gap; S3: Calculate the average expansion multiple K of the vermiculite particles at a constant temperature using the liner expansion thickness, the vermiculite thermal expansion coefficient α and the average diameter d; S4: Determine the proportion of vermiculite added according to the volume V of vermiculite added; S5: Calculate the added mass m of the vermiculite in this batch according to the average volume density ρ of the vermiculite.
2. A method for designing a carrier liner based on thermal expansion difference according to claim 1, characterized in that: The finite element method solves the gap volume difference after expansion to be V': V'=[(R2+S2) 2 +(R1+S1) 2 -R2 2 +R1 2 ]πL S1 is the average radial displacement of the carrier at a specific temperature, S2 is the average radial displacement of the metal shell, R1 is the radius of the carrier, R2 is the radius of the metal shell, L is the axial length of the carrier, there is an initial filling gap R2-R1 and a gap volume (R22-R12)πL, The expansion multiple of vermiculite is K, and the average volume density is ρ, then the vermiculite mass m is obtained: