Honeywell International Inc.
Method for controlling a trim-adjustment mechanism for a centrifugal compressor

Abstract:

A method for controlling an inlet-adjustment mechanism in an air inlet for a compressor so as to switch the mechanism in a binary fashion between open and closed positions for adjusting a flow area of the inlet. The method includes identifying a threshold line on a compressor map of pressure ratio versus corrected flow rate for the compressor, at which the inlet-adjustment mechanism is switched from one of its positions to the other. A fixed switch band straddling the threshold line can be used for determining when to initiate the switch of positions so as to time the switch to coincide with the operating point reaching the threshold line. Alternatively, a time to reach the threshold line can be instantaneously computed and compared to the actuator/mechanism response time.