Friction power consumption of mechanical seal
2017-07-21
Friction power consumption of
mechanical seal:
When the mechanical seal is working, the main source of frictional heat is on the one hand the friction heat generated by the end face seal pair in the friction process, and on the other hand, the stirring heat generated by the friction of the rotating element in the sealed medium. It can be seen that the total frictional power consumption N of the mechanical seal should include the frictional power consumption Nf of the end face seal pair and the stirring power consumption Na. which is:
The friction power consumption Nf of the end face seal pair can be calculated by the following formula
The calculation of stirring power consumption Na is related to the flow state of the sealed medium in the sealed cavity, and can be discussed according to the size of the Reynolds number that determines the flow state of the fluid and the turbulent flow. The formula for calculating Reynolds number is
The inner diameter of the sealed cavity in the formula, m;
Seal outer diameter, m;
Seal outer circumferential speed, m/s;
Density of the sealed medium, kg/m3;
Fluid dynamic viscosity, Pa·s.
When the Reynolds number Re>2000, the fluid is in a turbulent state. When the viscosity of the sealed medium is large, the stirring power consumption of laminar flow is
The stirring power consumption of turbulent flow is
Where L-the length of the rotating part of the seal, m.
If the seal is regarded as the inside of the sealed cavity-when rotating the cylinder, the following formula can be used to determine the mixing power consumption of the seal pair
In the formula, Cm is the loss coefficient of different flow regimes, and the expressions under various flow regimes are shown in Table 1-20.
Table 1-20 Expression of loss coefficient Cm for different flow regimes
National standard 103 mechanical seal 540.html,
Leakage of mechanical seal Mechanical seal friction heat and circulation (flushing) amount
