Discharge Coefficients of a Pre-Swirl System in Secondary Air Systems

The discharge behaviour of a “direct-transfer” pre-swirl system has been investigated experimentally. The influences of the pressure ratio and the swirl ratio as well as the influence of the receiver and stator geometry were investigated. The discharge coefficients of the pre-swirl nozzles are given in the absolute frame of reference. The definition of the discharge coefficient of the receiver holes is applied to the rotating system in order to consider the work done by the rotor. Numerical calculations carried out for a free expansion through the stationary pre-swirl nozzles show very good agreement with experimental data.Copyright © 2001 by ASME