Математическая модель манжетных уплотнений из фторопласта для агрегатов пневмоавтоматики ракетных двигателей

Abstract

The stress-strained state of a PTFE lip seal with conic side surfaces applied to seal the valve and piston of a rocket engine gas pressure regulator is studied using linear differential equations of elastic deformations of a thin cylindrical shell. The one-dimensional aero elasticity problem arising in the analysis of PTFE lip seal and metal cylindrical wall contact is set and solved. Based on the problem a method for computing the effective clearance and gas leakage through the seal is developed. A new computing method for determining the contact force between the lip seal and the cylindrical surface of the sleeve or rod taking into account the penetration of gas pressure or lubrication inside the sealed gap is proposed. The theoretical laws of elastic-plastic deformation of fingers of a finger spring are studied; the method for calculating the pressure of the fingers on the wall of the PTFE lip seal is developed. The methods of experimental study of friction and gas leakage through a seal as well as the test results specifying the known dependencies of friction on the sealing pressure and sliding speed of PTFE are presented. New formulas for estimating the friction force in a flexible seal, which can be used at the stage of unit conceptual design, are proposed. The formulas take into account the elastic and plastic properties of PTFE, namely, the Young’s modulus and the Brinell hardness number.