BEARING LOAD ANALYSIS OF RECIPROCATING PISTON COMPRESSORS

Abstract

Many problems in today’s industrial environment require smart modeling assumptions in order to make them numerically accessible with an acceptable amount of effort. This case study shows how a field problem (main bearing failures) is turned into a numerical model: we present a bearing force analysis of a 5-throw reciprocating compressor with severe problems on its third main bearing. Inertial and gas-dependent forces are calculated. The crankshaft is modeled as a uniform beam; its load-dependent deformation and the resulting bearing loads are estimated based on Clapeyron’s three-moment equation with the assumption of zero bearing clearances. The resulting calculation time is < 1s for a 360-degree load cycle, allowing detailed studies that yield conclusive results: polar load diagrams clearly confirm that the problematic bearing is exposed to the highest loads in operation. The short calculation time allows for parametric studies investigating the effect of lower reciprocating masses, partial load conditions, counterweights, different crankshaft designs, or combinations of the above.