Bleed air control by mixing.

摘要

A gas turbine engine bleed air system (10) in which air flow from a high pressure (HP) and a low pressure (LP) compressor stage of a gas turbine engine are mixed together, by controlling the pressure at the outlet of a proportional valve, (PRV) the pressure is controlled by modulating the flow area of the proportional valve (HPSOV) through which the high pressure air flows in order to achieve a scheduled pressure value, where the scheduled pressure value is determined as a function of a temperature error at a location downstream of the proportional valve (PRV) in the bleed air system. <IMAGE>