EXPERIMENTAL TECHNIQUE FOR DETERMINING THE EQUIVALENT GAP FOR A CYLINDER PISTON SEAL OF A SLOW-MOVING LONG-STROKE STAGE IN A DYNAMIC FORMULATION

The paper considers the basics defining the terms of conditional and equivalent clearance in a cylinder piston seal, gives their distinctive description and importance in the calculation of mass flows. We highlighted the absence of recommendations regarding the parameters of the equivalent gap for low-speed compressor stages. An experimental technique and an experimental stand for determining the parameters of the equivalent gap were developed. The conducted studies showed that the value of the equivalent gap had a strong dependence on the cycle time and varied from 0.5 to 1.5 microns depending on the parameters of the working gas and the number of seals installed on the piston. We determined that in the pressure range from 0.1 to 12 MPa with a cycle time from 2 to 4 s, it is not advisable to install more than 7 cuff seals, since the change in the equivalent gap value is insignificant.