Nozzle Admittance and Damping Analysis Using the LEE Method

作者：Wang Mu-xin; Liu Pei-jin^*; Yang Wen-jing; Wei Xiang-geng

来源：INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES, 2017, 34(1): 33-41.

DOI：10.1515/tjj-2015-0050

• nozzle admittance
• nozzle damping
• combustion instability
• linearized Euler equations

The nozzle admittance is very important in the theoretical analysis of nozzle damping in combustion instability. The linearized Euler equations (LEE) are used to determine the nozzle admittance with consideration of the mean flow properties. The acoustic energy flux through the nozzle is calculated to evaluate the nozzle damping upon longitudinal oscillation modes. Then the parametric study, involving the nozzle convergent geometry, convergent half angle and nozzle size, is carried out. It is shown that the imaginary part of the nozzle admittance plays a non-negligible role in the determination of the nozzle damping. Under the conditions considered in this work (f(star) = 1,000 Hz, de(star) = 0.18 m), the acoustic energy flux released from the nozzle with a 30 degrees convergent half angle is highest (30 degrees: 6.0 x 10(4) kgs(-3), 45 degrees: 5.2 x 10(4)kgs(-3), 60 degrees: 4.9 x 10(4) kgs(-3)). The change of nozzle convergent geometry is more sensitive for the large size nozzle to increase the nozzle damping.

• 出版日期2017-4
• 单位西北工业大学