Mechanical Seals Manufacturer In China » Ultra-high pressure seals http://www.hfanlx.cn Professional Mechanical Seals,Rubber Mechanical Seals、Carbone Sealts In China Fri, 03 Sep 2010 09:40:57 +0000 http://wordpress.org/?v=2.8.2 en hourly 1 Ultra-high pressure seals the finite element analysis http://www.hfanlx.cn/archives/20 http://www.hfanlx.cn/archives/20#comments Thu, 28 May 2009 02:12:54 +0000 admin http://www.hfanlx.cn/?p=20 For petroleum, chemical and other areas of the high-pressure sealed containers, the seals working environment, prone to severe deformation and intensity of inadequate disclosure failures. Using finite element method study of high-pressure sealing contact with the container strength and deformation problems, the use of ANSYS and MATLAB software analysis of the sealing surface contacts in a multi-pressure conditions, the Composite stress distribution and seal deformation, and reveal its trend for a new type of seal design, material selection to provide an analytical basis. Key words: ultra-high pressure vessel; seal devices; contact analysis; finite element method
The introduction of a new type of ultra-high pressure containers (pmax = 102 MPa) with the exception of sand, sewage functions, is very important in the desert oil fields of the chemical plant, the upper part of Figure 1 Schematic diagram of the container. Figure 1 Schematic diagram of ultra-high cooling container 12 hoop ; 22 seals; 32 cap; 42 bolts; 52 cylinder design requirements in accordance with the container, sealing cone taper to 8.5 °, the contact cap and the cylinder cone taper to 10.5 °, sealed with the cap up and down plane and the cylinder with the initial gap of D = 0.55mm, as shown in Figure 2. in the circumstances is not contained, sealed up and down cone and cylinder with a conical cap with the contact for the two cone Line contact; by the set, the sealing line of contact with the expansion cone by the torus for small contacts, increasing the contact area. horizontal clamp bolt tightened, the seal with the role of relying on the cone so that the cap and the cylinder in the axial occurrence of relative movement of the card into the hoop on the volume of the axial force generated in order to achieve pre-sealed. when the container internal pressure to rise, the media pressure generated by axial
Transmission of power from the roof to the hoop, hoop along the trend of the expansion cone bolt from horizontal to achieve the self-locking pull. Figure 2 high-pressure seals and cone diagram node number on the cone é2;? 2 plane;? 2 under the cone; ì2 plane;? 2 inner face of the sealed container, the seals in the state of the contact pressure distribution and synthesis of stress, deformation of the size of seals and other factors have a decisive effect on the sealing effect is the key to the design of pressure vessel technology. In this paper, finite element method, using MATLAB software AN2SYS and analysis of the low pressure and high pressure seals, such as state of the contact pressure, the integrated stress and deformation of seals, the results of research and development of high-pressure vessel has a .1 a good guide for finite element model of the overall exposure to 1.1 contact seals the top and bottom of the cone and cylinder with a conical cap with a typical non-linear contact problem [122]. not under pressure, the cone contacts the two contacts for the line; pressure after sealing cone from the line of contact with the expansion of access for small torus. the complexity of the performance of the following two points for the .1) and cylinder seals, cap the size of the contact area and the relative position and the contact state is unknown in advance, and with changes in load and time required to solve identified in .2) and cylinder seals, top of the contact between the stress and deformation is nonlinear. Solving constraints to unilateral constraints. The method bound to the tangential contact conditions and contact with the two conditions. Act to include access to the contact interface to the law of non-penetration and the pressure to the contact force for the state to determine whether to contact conditions; tangential contacts to judge the condition that the two objects have come into contact with surface contact state between the specific conditions. The range of conditions characterized by unilateral constraints and strongly nonlinear .1. 2 contact with the mathematical model 1.2 . 1 contact the election principle of virtual displacement cone cap, seals on the cone, respectively, as A, B for solving the two regions, each in contact with the surface of the border can be seen as the border to定力time t + $ t-shaped spaces within the conditions equivalent to the balance principle of virtual displacement can be expressed as ∫ t + $ tt + $ tSijDt + $ teijt + $ tdV-t + $ tWL-t + $ tWI-t + $ tWC = ΣA, Br = [∫ t + $ tvrt + $ tSrijDt + $ tert + $ tijdV -t + $ tWrL-t + $ tWrI-t + $ tWrC] = 0 where: t + $ tWL = ΣA, Br = t + $ tWrL, t + $ tWI = ΣA, Br = t + $ tWrI, t + $ tWC = ΣA , Br = t + $ tWrC = ΣA, Br = ∫ t + $ tt = $ tsrcFriDur t + $ tidS = ∫ t + $ tt = $ tscFAJ (DuAJ-DuBJ) t + $ tdS a variety of more than t + $ tWL for time t + $ t Euler stress configuration; Dt + $ teij, Duri is the infinitesimal strain variation; t + $ tWL for the role of time t + $ t load configuration on the outside of the virtual work; t + $ tWI to act on the moment t + $ t configuration on the virtual work force of inertia, if the effects of inertia force can be ignored, then WI = 0; t + $ tWC for the role of t + $ t in contact with the surface of contact force at all times of the virtual work; V, S and Q, respectively, for objects the size of , surface area and mass density; t + $ tFAi and t + $ tFBi were conical cap, seals on the cone t + $ tSAC, t + $ tSBC contact pressure on the t + $ tFA and t + $ tFB along the general coordinates i = x, y, z the weight, and t + $ tFAi and t + $ tFBj is along the local coordinate system of their weight. contact interface t + $ tSC the regional and state is by solving the check and search before a given
Of. Contact pressure t + $ tFA and t + $ tFB is the unknown quantity, determined by solving .1. 2.2 conditions for the introduction of contact constraints by solving the Lagrange theory of knowledge, contacts seal pan-cone function can be expressed for 0 = 0U +0 CL. Type in the: 0U, for contact constraints do not include the total potential energy, 0CL is a Lagrange multiplier method to introduce additional contact constraints functionals, relative sliding cone surface, the contact problem of virtual work equation can be written as t + $ tWC =- (D0CL) u = ∫ – t + $ tt + $ tScKN × [(DuAN-DuBN)-L (uqJ? uq) × (DuAJ-DuBJ)] t + $ tdS (J = 1,2)-type can be seen above, for sliding contact state with or without friction, only an independent Lagrange KN, solving the need to add only a law can not be used to bound into the conditions of: uAN – uBN-tgqN = 0, uAN, uBN respective point of contact for the top cone, the cone seal surface contact point in the direction of law to the incremental displacement, tgqN is the contact point cone cap, seals on the cone contact point in time t the location of the contact method to measure the distance direction. Lagrange method with the introduction of the contact interface constraints, the use of recursive iterative Newmark method can be sealed pressure vessel contact Finite Element Equations solution.
1.3 High Pressure Vessel sealing contact with the issue of finite element simulation 1. 3.1 modeling ideas and as a result of sealing cone of the conical cap and the cylinder line contact for initial contact, can not afford a lot of axial force Therefore, locking in the clamp force will produce a certain deformation of the taper, leading to the roof with flat sealing contact with the cylinder-plane contact under seal. ANSYS to create contact, if only consider the cone from top to bottom, ignore the upper and lower plane load directly, as a result of the carrying capacity of the axial line of contact is extremely poor and unstable model, the calculation can not be correct. In order to enhance convergence of the calculation, the results have been satisfactory, the usual approach is to pre-load the target surface contact surface to the initial penetration, is about to Figure 2 in the gap between the upper and lower pressure level and also create a contact print, using upper and lower seals add auxiliary bound plane, so that there is sufficient load-bearing capacity, the calculation can achieve more desirable results. 1. 3.2 conditions of load calculation unit type PLANE 42, the definition of symmetry axis, calculating the initial conditions are as follows: (1) does not consider the roof of the self; (2) interception of part of the lower cylinder axial restraint increases; ( 3) cylinder wall increases pressure p1; (4) to exert pressure on the clamp ps.1. 3. 3 clamp load pressure ps selected as the basis for self-locking seal type, clamping force clamp pressure with the cylinder and changes in the internal pressure cylinder only know that circumstances can not be pressed at the same time to identify and clamp the upper and lower cone pressure seals. in as close as possible to real
The occasion of the work under the premise can be considered the operator of ANSYS, the following programs: (1) upper and lower sealing cone, from top to bottom and top plane, cylinder to create a total of four contacts. (2) to ensure that both seals in the high-pressure or low pressure cone on the case are sealed, there is no contact pressure from top to bottom plane or very small. that is, in a variety of different conditions, using ANSYS spreadsheet 0.55 mm, respectively, by pressure clamp on the normal pressure, the pressure than the cylinder pressure to be slightly larger body. correspond to the pressure as listed in Table 1. Table 1 and the clamp cylinder pressure corresponding to the value of 061,860,102 Table MPa air pressure inside the pressure clamp 0.67.82478.51331. 3.4 Multi-Seal Analysis The following discussion of the body tube gas pressure 0,6,18,60,102 MPa, respectively, the seals on the cone (the cone and the cone of symmetric, so only on the cone) of the contact pressure, stress and the integrated node Drive to the deformation conditions, the relevant curve in Figure 4 as shown in Figure 6 [3]. 1) The contact pressure can be seen from Figure 4 cone seal contact pressure distribution on the trend: no matter what kind of gas pressure in the state, are the node 1 that the initial point of contact for the following line under the pressure that the contact pressure Fig.4 integrated stress curve of Figure 5 Figure 6 radial deformation curve of the largest power; to participate in the nodes are in contact with the cylinder pressure increases within the increases. in high pressure on the cone when the 2,3 node also participated in the contacts of the contact cone into contact with the line contact Cyclotella .2) Integrated stress can be seen from Figure 5, the conical seal With the cylinder internal pressure stress increases, node 1 and the cone with the rounded corners on the plane there is stress concentration; in the same working conditions: low pressure, the stress cone seals on to the next followed by the increase in ; high-pressure, the first increase and then decreased, and then has been on the increase in the seals on the cone with the rounded corners on the largest plane to more than 1000 MPa, so the requirements of the material is relatively high .3) of radial deformation as shown in Figure 6 , in the low-pressure seals, the deformation of the cone are negative, this is because the clamp locking force, air pressure inside small, not enough to seal the expansion along the radial outside. high-pressure, the seals on the cone some deformation of node negative, the next part of the node is positive, indicating that seals the inner surface recessed, large contact area .2 conclusions 1) ultra-high pressure seal when squeezed by the strong, easy to seal materials have a large plastic deformation and loss of flexibility, so that sealing performance of a sharp decline, resulting in duplication of the low utilization rate of seals, it should be made with reference material largest integrated ANSYS calculated stress, after a number of factors integrated .2) processing seals must maintain cone face the overall consistency, avoid contact with large localized surface deformation Bump .3) ultrahigh-pressure fluctuations in pressure sealed containers, and instantaneous temperature rise, lead to increased seal plastic rheology, resulting in large deformation, and even a partial cracks. At the same time as a result of pressure changes in the load cycle, upper and lower seal surface contact fatigue and even prone to wear and tear. References [1] WANG Xu-cheng, SHAO Min. the basic principles of finite element method and numerical methods. 2nd ed. Beijing: Tsinghua University Press, 1997 (next to No. 1072) 7501 No. 6 GB costs, such as: ultra-high pressure seals the finite element analysis

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