Theoretical and Experimental Studies for the Transient Response of Cavity

Abstract

During the transient state of aero-engine, cavity has evidently transient characteristics in the secondary air system. To investigate transient characteristics, theoretical and experimental studies were implemented for both static and rotating cavities. First of all, the typical transient response phenomena in secondary air system were investigated based on the basic concepts of the dynamic process. According to the basic theory of gas dynamics, the causes of transient phenomena were analyzed in two aspects, external disturbance, and system physical properties. Several dimensionless parameters were introduced to analyze the transient response characteristics of air system. Second, the experimental results of the static cavity indicated that the actual response time increased with the increase of the inlet pressure. The experimental results of the rotor-stator cavity showed that the low rotational speed on the response process had little effect, and the response time gradually increased when the speed continued to increase. Third, the test results of multiple components suggested that when the valve was opening the inlet pressure of the static cavity increased quickly and then reached a stable value, but the pressure of the static cavity, stable pressure cavity and rotor-stator chamber rose gradually. It was also obtained the actual response time of them was increased. The closer the measuring points were to the disturbance source, the shorter the delay time was.