螺旋槽端面剖分式机械密封性能研究

发布时间：2018-05-19 01:11

本文选题：剖分式机械密封 + 螺旋槽　；参考：《南京林业大学》2014年硕士论文

【摘要】：与普通的穿套在轴上的机械密封相比，剖分式机械密封安装拆卸方便、经济性好。本文以螺旋槽端面剖分式机械密封为研究对象，对其密封性能和剖分环变形规律进行分析。首先，针对给定的工况参数，设计出一款新型剖分式机械密封，，在剖分动环端面开螺旋槽造型，利用ANSYS Fluent进行数值模拟，研究了工况参数、槽型几何参数对螺旋槽上游泵送密封性能的影响，优化螺旋槽型的结构参数；其次，分析了螺旋槽端面剖分式机械密封温度场、热变形及热-结构耦合变形规律，研究了主轴转速、冲洗量、膜厚和箍筋压应力对剖分式机械密封温度场、热变形及热-结构耦合变形的影响。具体内容如下： (1)设计了一款安装、更换便捷，具有自紧密封的能力，适用于高压工况的新型剖分式机械密封。其主要特点在于：动静环为对开半环，安装、更换方便；动静环在承受介质压力时，剖分面、动环和动环座、以及静环和静环座之间的接触压力随被密封介质压力的增大而增大，提高了被密封介质流出密封面的阻力，具有自紧密封的能力； (2)利用ANSYS Fluent对螺旋槽液膜密封进行数值模拟，研究结果表明： (a)端面槽形几何参数适宜的取值范围为：12°α18°,5μmh10μm,0.5β0.8，0.4γ0.7,8Ng14。 (b)正交试验表明：槽深、槽宽径宽比对泵送量的影响显著；槽深、槽宽径宽比对开启力的影响特别显著，槽数对开启力影响显著；槽深对轴向刚度的影响特别显著，螺旋角、槽坝长比对轴向刚度影响显著。 (3)利用ANSYS有限元分析软件热-结构耦合分析模块，对螺旋槽端面剖分式机械密封剖分环环端面温度场、热变形及热-结构耦合变形进行了研究。可得出以下结论: (a)端面温度最高值出现在密封端面内径处，剖分静环端面温度明显高于剖分动环端面温度，且温度使密封端面和分型面产生正锥度变形，而箍筋压应力能够有效抑制端面及分型面的变形。 (b)随着冲洗量的增加，剖分静环端面的温度逐渐降低，端面温度差增大，热变形锥度增大；端面热-结构耦合变形增大，变形锥度增大；其次，分型面X轴向热变形增大，变形锥度增大。剖分动环端面的温度逐渐降低，端面轴向热变形减小，变形锥度减小；端面热-结构耦合变形减小，变形锥度值减小；其次，分型面热变形减小，变形锥度减小。 (c)随着膜厚的增加，剖分静环端面的温度逐渐降低，热变形减小，热变形锥度减小；端面热-结构耦合变形值减小，变形锥度值减小；其次，分型面X轴向热变形减小，变形锥度减小。剖分动环密封端面的温度逐渐降低，端面热变形减小，变形锥度减小；端面热-结构耦合变形值减小，变形锥度先减小后增大，膜厚达到4μm时，锥度最小；其次，分型面X轴向热变形减小，变形锥度减小。 (d)主轴转速对剖分动环和剖分静环的影响规律一致。随着主轴转速的增加，端面的温度增大，端面热变形增大，变形锥度增大；端面热-结构耦合变形值增大；其次，分型面X轴向热变形增大，变形锥度增大。 (e)随着箍筋压应力增大，剖分动环和剖分静环的耦合变形值随着箍筋压应力增加而增大，变形锥度增大。因此，箍筋压应力并不是越大越好，必须针对给定工况，在保证密封基础上，选择合适的箍筋压应力。
[Abstract]:Compared with the mechanical seal on the shaft, the split type mechanical seal is easy to disassemble and has good economy. In this paper, the sealing properties of the spiral groove face and the deformation law of the split ring are analyzed. First, a new type of split mechanical seal is designed for the given working conditions. By using ANSYS Fluent for numerical simulation, the influence of working condition parameters and groove geometric parameters on the performance of the upstream pumping and sealing of the spiral groove is studied, and the structural parameters of the spiral groove are optimized. Secondly, the temperature field, the thermal deformation and the thermal structure coupling deformation of the spiral groove face are analyzed. The influence of spindle speed, washing amount, film thickness and pressure stress on the mechanical seal of split type, thermal deformation and thermal structure coupling deformation are studied.
(1) a new type of split type mechanical seal is designed for installation, easy to replace, self tight seal and suitable for high pressure conditions. Its main features are: the dynamic and static ring is the open half ring, the installation, and the replacement are convenient; the dissection, the moving ring and the movable ring, and the contact pressure between the static ring and the static ring seat when the dynamic ring is subjected to the pressure of the medium. With the increase of the pressure of the sealed medium, the resistance of the sealed medium flowing out of the sealing surface is enhanced, and the self sealing ability is sealed.
(2) numerical simulation of spiral groove liquid film seal is carried out by using ANSYS Fluent.
(a) the suitable geometry value of the groove geometry is: 12 degree alpha 18 degrees, 5 mh10 mh10 m, 0.5 beta 0.8,0.4 0.7,8Ng14.
(b) orthogonal test shows that the influence of the groove depth and the width width of the groove on the pump volume is remarkable; the depth of the groove and the width and width of the groove have a special effect on the opening force, and the number of grooves has a significant influence on the opening force; the groove depth has a special effect on the axial stiffness, and the spiral angle and the length of the groove and dam have a significant influence on the axial stiffness.
(3) using the thermal structure coupling analysis module of ANSYS finite element analysis software, the temperature field, thermal deformation and thermal structure coupling deformation of the spiral groove end section mechanical seal are studied. The following conclusions are obtained.
(a) the maximum end face temperature appears at the inner diameter of the seal face. The temperature of the end face is obviously higher than the end surface temperature of the dissection ring, and the temperature makes the seal face and the parting surface have a positive taper, and the pressure stress of the stirrup can effectively restrain the deformation of the face and the subsurface.
(b) with the increase of the flushing amount, the temperature of the end surface of the split static ring is gradually reduced, the temperature difference of the end face increases, the taper of the thermal deformation increases, the coupling deformation of the end face increases and the deformation taper increases. Secondly, the axial thermal deformation of the split surface increases and the deformation taper increases. The temperature of the end face of the split ring is gradually reduced and the axial thermal deformation of the end face decreases, and the end face axial thermal deformation is reduced and changed. The taper decreases, the thermal structural coupling deformation decreases, and the deformation taper decreases. Secondly, the thermal deformation of the parting surface decreases and the deformation taper decreases.
(c) with the increase of the thickness of the membrane, the temperature of the end surface of the split static ring is gradually reduced, the thermal deformation decreases, the taper of the thermal deformation decreases, the coupling deformation value of the end face is reduced and the deformation taper decreases. Secondly, the axial thermal deformation of the split surface decreases and the deformation taper decreases. The temperature of the seal end face is gradually reduced, the end face deformation decreases and the deformation of the end face is reduced. The deformation of the end face is reduced and the deformation is deformed. The taper decreases, the thermal structure coupling deformation value decreases, the deformation taper decreases first and then increases. When the film thickness reaches 4 m, the taper is the smallest. Secondly, the X axial thermal deformation decreases and the deformation taper decreases.
(d) the influence of the spindle speed on the dissection ring and the split static ring is the same. With the increase of the spindle speed, the temperature of the end face increases, the end face heat deformation increases, the deformation taper increases, the thermal structural coupling deformation value of the end face increases, and the X axial thermal deformation increases and the deformation taper increases.
(E) with the increase of the pressure stress of the stirrup, the coupling deformation value of the split dynamic ring and the split static ring increases with the increase of the pressure stress of the stirrup, and the deformation taper increases. Therefore, the pressure stress of the stirrup is not the greater the better, and the suitable pressure stress must be chosen on the basis of the given condition.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH136

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