Inter Chamber Leakages in Orbit Motors- Estimation by Modeling and Simulation in FEM and Fluent® Environment

Abstract

An analysis is carried out to predict inter-chamber leakage flows through the two transition active contacts, which separate the high pressure chambers from the adjacent low pressure chambers, in the cycloidal class toothed starring of ORBIT® motors. Among geometrically form closed contacts which separates chambers from each other, few active contacts support high reaction loads during the process of transmitting torque in such unique LSHT hydrostatic units. Contact deformations in those contacts generate gaps in the other contacts for a partial period of time. High inter-chamber leakages occur through such gaps at transition active contacts. In an attempt to visualize the characteristics of such leakages, which contribute towards the poorer leakage characteristics of such machines, detail mapping i.e., magnitudes, rotational position etc., of such gaps of a commercially available unit, are carried out. For estimating gaps FEM technique is used. The FEM results have very good agreement with the results predicted earlier using trial method. Such gaps are difficult to measure as the contact positions are inaccessible to equip any conventional measuring instrument. The characteristics of leakage flows through such gaps are then established by CFD analysis using Fluent® in Ansys environment.