Some Aspects of Influence of Turbopump Unit Fabrication and Assembly Method on Seal Clearances

Abstract

Each element of turbo-pump unit has its own dimensions, tolerances of form and surface arrangements that differ from the rated ones. When assembling a turbo-pump unit they are located with some skew due to the mounting offsets of the rotor and stator sealing surfaces. Such skew arise due to a combination of hard-to-predict factors, such as the inaccuracy of the machine, the clearance of the centering surfaces, the rigidity in machining, the reliability of the fixing of the component, the state of the component, the balance of the system, and so on. The main factors affecting the installation bias of the rotor and stator sealing elements include the structural diagram of the unit, the workflow for manufacturing component parts, the workflow of assembling and controlling quality. The present article considers the dependencies for calculating the values of the mounting bias. It is necessary to reduce the effect of the installation bias on the size of the sealing gap to reduce leakage in the seals of pumps and turbines.