Study On Oil-soaked End Face Mechanical Seals Tribological Properties Of The Square Hole

Oil-soaked face square hole mechanical seal is a new type of mechanical seal technology, compared with the ordinary mechanical seal, which can improve the friction state of the mechanical seal friction pair, prolong the life of sealing, improve the tribological properties effectively. This paper focuses on considering the lubricating properties of end of oil-soaked end square hole mechanical seal analytical method and finite difference numerical calculation method were used respectively to solve the end fluid lubrication Reynolds equation, and conduct in-depth analysis of lubricating properties for seal faces. Some tribological properties such as the pressure distribution of the end liquid film, opening(carrying) force formed of the end liquid membrane pressure, friction torque, the friction coefficient and the leak rate of the end were calculated respectively. The influence of operating parameters and structural parameters for the tribological properties were investigated. While the fin theory was used to calculate the temperature distribution of oil-soaked microporous mechanical seal face.The main research contents and conclusions were as follows:1. An one-dimensional analysis model has been developed for oil-soaked square hole mechanical seal liquid film pressure distribution, based on the lubrication model of ladder slider, the calculation formula of such the mechanical seal radial and circumferential average liquid film pressure distribution were derived.The mechanical seal radial and circumferential average liquid film stress distribution were obtained.2. Fluid lubrication Reynolds equation for the face is solved by using the finite difference method, and got the three-dimensional liquid film pressure distribution under the different pressure and medium conditions by using the software MathCAD. The results show that, pressure difference and viscous of medium had a direct impact for its film pressure distribution.,and compared with the results of analytic method, its value are basically identical.3. Analytical method and finite difference method was used respectively to study the different operation parameters and structure parameters on the influence of the oil-soaked square hole mechanical seal sealing performance. Specific results were as follows:(1) The law obtained by the two methods for the impact of different operating parameters and structure parameters on the oil-soaked square hole mechanical friction tribological properties were basically identical;(2) With the greater speed of the sealing ring, the linear of the seal opening force, liquid film stiffness, leakage rate, the friction torque and the friction coefficient became greater;(3)with the greater of the medium viscosity, the seal opening force, liquid film stiffness,friction torque and the friction coefficient become larger, and the leakage rate became smaller. When the viscosity is more than2×10-3Pa·s, the decrease leakage rate and the friction coefficient are basic flat;(4) When the hole section film thickness is less than5μm, the depth of the hole in the range of2～6μm, the tribological properties is better.4. Oil-soaked square hole mechanical seal temperature distribution model was established, fin theory was used to calculate the axial temperature distribution the of average temperature and static ring for the face of mechanical seal under different operation parameters and structure parameters. To get specific results are as follows:(1) Under the same conditions of medium viscosity, rotation speed and mask thick, oil-soaked square hole mechanical seal has a lower average temperature of face than the normal mechanical seal;(2) The average temperature of the oil-soaked square hole mechanical seal face increases with the increase of the medium viscosity and speed, among them the medium viscosity’s influence on the average temperature of the face is significant;(3)The average temperature of the face for oil-soaked square hole mechanical seal decreases with the increase of the hole section film thickness. When film thickness is less than2μm, reducing trend changes dramatically; and when the film thickness is greater than4μm, the decrease trend flattens out;(4) The temperature distribution of dynamic and static ring diminish gradually along the axial position from the contact face to the two adiabatic boundaries, gradually close to the ambient temperature.