Seeking help with issues regarding the face pressure and spring pressure of mechanical seals
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This post was last edited by “I’m just a beggar” on June 7, 2024, at 08:06. As a beginner in mechanical seal design, I’ve encountered a rather confusing problem: the face pressure is calculated based on the spring pressure, while the spring pressure, in turn, is calculated based on the face pressure. I’m quite puzzled. Referring to Gu Yongquan’s “Mechanical Seal Design Manual”, a series of recommended ranges are provided; for instance, the recommended value of 0.3–0.2. However, this range encompasses countless variable factors, and it’s impractical to conduct experiments for each individual case. Therefore, I would like to ask everyone: should this parameter be set based on experience, but still within this specified range? Then, parameter adjustments can be made based on subsequent usage or after leak detection through dynamic pressure testing; or ANSYS can be used for simulation to obtain specific data Is there any experienced teacher who can teach me? I’m willing to offer silver as compensation.
In mechanical seal design, the end face specific pressure and the spring specific pressure are indeed interdependent. Typically, both of these parameters need to be determined based on the actual application scenario, sealing material, and design experience. You can initially set a value based on the range recommended in the manual, and then verify and adjust these parameters through experimental testing or simulation analysis (such as using ANSYS). In practice, it is often necessary to make multiple iterative adjustments based on the test results of the sealing performance in order to achieve the best sealing effect. There is no fixed formula; design is primarily guided by experience and experimental data. .
In other words, there is no fixed formula or value to determine these two parameters; it is only through past experience or actual testing that it can be determined whether they meet the design objectives
Yes, to be precise, the determination of the end-face specific pressure and the spring specific pressure relies on design experience, material properties, and actual application conditions. There is usually no fixed formula to directly calculate these two parameters; instead, they need to be adjusted and verified through actual experimental data, simulation analysis, and past successful cases. Therefore, at the initial design stage, a preliminary setting can be made based on the recommended ranges and historical data from similar applications, followed by gradual optimization and adjustment through experimental results and performance feedback from actual use. .
Actually, it’s mainly about the balance of forces. Spring specific pressure is another pre-applied load in addition to the fluid-induced load, whereas end-face specific pressure (end-face micro-protrusion contact specific pressure) is the load-bearing force. For contact mechanical seals in a mixed-lubrication state, the end-face specific pressure must be coordinated based on the applied loads (fluid-induced specific pressure and spring-specific pressure) as well as the loads that need to be supported (the bearing capacity of the fluid film). Pm = B*P + Ps – K*P, where Pm is the end-face contact specific pressure, B is the balance ratio, Ps is the spring specific pressure, and P is the pressure difference exerted on the seal. For contactless mechanical seals, since they are in a full liquid film lubrication state, there is no contact pressure bearing capacity.