复杂工况渣浆泵用耐蚀耐磨型机械密封性能及磨损机制研究

A mechanical seal with the two ways and double rows directional diamonds texture in slurry pumps is a research object in this project, in order to solve the problems of the poor liquid film stability and the seal failures of after seal face particle wear and partial contact because of end face deformation due to stress or uneven heating in the harsh working environment of the high solid content, abrasion and strong corrosive medium coexisting. 1) Considering liquid membrane cavitation and actual running situation, the two ways and double rows diamonds texture is processed in the end face, in order to study the influence of operation and structural parameters on sealing performance and wear mechanism; 2) A three-dimensional flow/solid/heat coupling mathematical model of the end seal with the two ways and double rows directional diamonds texture is constructed, in order to control end face deformation by researching the macrostructure of sealing rings, axial length and position of each support point, so as to analysis the film thickness, end surfaces temperature, dynamic/static ring thermal deformation law and seal performance change. 3) The influence of end face wear is considered on the basis of the steady-state thermodynamic coupling model, the thickness of the liquid film was modified by wear, in order to study the grinding law of seal face and evolution of sealing performance. 4) The correctness of the theoretical results of the mechanical seal with the two ways and double rows directional diamonds texture and feasibility of the optimal geometric parameters are validated by using the experimental method, the anti-friction and the reduction leakage mechanism of the end face seal with two ways and double rows directional diamonds will be revealed under different working conditions, so as to provide dependence for the optimization design of liquid seal structure in the high temperature, high pressure, high speed and slurry medium, it will be helpful for the liquid seal to solve of abrasion and deformation, and to extend its application fields.

本项目以渣浆泵用双向双列方向性菱形孔端面密封为研究对象，旨在解决因高固含量与腐蚀介质并存的恶劣环境中，极易导致液膜稳定性差、端面颗粒磨损和热力变形产生局部接触而失效等问题。1)考虑液膜空化和实际运行情况，在端面上加工出菱形孔织构，研究操作和结构参数对密封性能的影响及耐磨机理。2)构建织构端面密封三维流/固/热耦合数学模型，通过研究密封环宏观结构、轴向宽度和尾部支撑位置达到控制变形的目的，分析膜厚、端面温度和动/静圆环热力变形及密封性能变化规律。3)在稳态热力耦合模型基础上考虑端面磨损的影响，通过磨损量对膜厚进行修正，研究密封端面磨合与密封性能演化规律。4)实验验证理论成果的正确性及最佳几何参数的可行性，揭示双向双列菱形孔端面密封减摩、减漏特性及机理，为高温、高压、高速及浆液介质下液体密封结构优化设计提供依据，对于解决液体密封端面磨蚀和变形失效，拓展其应用领域具有极为重要意义。

项目为解决渣浆泵用机械密封在高固含量与腐蚀介质并存恶劣环境中，极易导致液膜稳定性差、端面颗粒磨损和端面变形等产生局部接触而失效问题。完成以下研究：考虑液膜空化和实际运行情况，构建织构端面密封三维流/固耦合数学模型，通过研究密封环微观孔型结构、宏观结构(即密封系统辅助部件的位置及密封环尺寸)达到控制变形的目的，分析压力场、膜厚、温度场和动/静圆环变形及密封性能变化规律，得到适合研究工况条件下的最优宏观和微观结构尺寸范围，最佳微观结构尺寸：反向开孔比为0.25~0.5、外倾斜角为-20°~50°、孔深度为3.5~4.5µm、面积比为0.03~0.051时，双向菱形孔端面密封可获得较好的性能参数；最佳宏观结构尺寸：平衡比B、尾部支撑位置l1、O型圈位置l2及静圆环外径ro1显著影响密封端面的密封性能。当平衡比B=0.7-0.85、中高压时艉轴点在2点，低压时取在5点时，密封系统可达到较好的密封性能；另外，O型密封圈位置l2和静环外径尺寸ro1对端面径向锥度变形具有较大影响。考虑端面磨损的影响，基于分形理论分布建立渣浆泵用机械密封面上的磨损预测模型、机械密封面泄漏预测分形模型及密封端面温度分布模型，研究密封面磨损量、泄漏量及温度的演化规律。实验验证理论成果的正确性及最佳几何参数的可行性，揭示双向双列菱形孔端面密封减摩、减漏特性及机理，为高压、高速及浆液介质下液体密封结构优化设计提供依据，对于解决液体密封端面磨蚀和变形失效，拓展其应用领域具有极为重要意义。