6-Stage Process Compressor Rerate

A CENTAC six-stage, integrally geared process compressor was rerated to increase the flow, pressure rise, and efficiency over those of the original machine. The primary design challenge was the requirement for a large increase in process flow with no changes allowed to the outside casing, deswirl vanes, and intercoolers, and only limited changes allowed to the inducer dimensions. Careful stage matching was used to deliver a wide operating range, very stable individual and overall head characteristics, and efficiency levels that exceeded those of the existing machine. Initially, a full set of rotating and stationary hardware for the existing design was shipped to Turbo Solutions. We completed detailed hand-measurement and laser-scanning of the existing hardware, and then built up a complete solid model of the entire machine. This baseline geometry was analyzed aerodynamically using meanline and CFD tools and structurally using FEA, and a cycle model of the six-stage machine was created to study the stage matching. The entire machine was then redesigned for improved stage matching, increased flow and pressure, and higher efficiency. We created detailed manufacturing drawings of the redesigned and modified components, and procured and shipped to the customer two full sets of replacement hardware (impellers, diffusers, and shrouds). On-site support was provided for the reassembly and test of this machine. The redesigned machine met all aerodynamic and mechanical performance goals on the first build.