Numerical investigation of flow oscillation in a contracting and expanding passage subject to vibration

Stable and accurate fuel supply and distribution is a key issue in flow regulation. Because of the small space of a hypersonic vehicle, the contracting and expanding passage is often used to measure the flow rate. However, we experimentally found that the contracting and expanding passage vibration leads to flow oscillation. The flow oscillation significantly affects the fuel flow measurement, and even threatens the safety of the filling process. To understand the mechanism of flow oscillation, a three-dimensional model of a contracting and expanding passage with hydrocarbon fuel was established. After validating the present model with experimental results, a detailed discussion was presented to study the hydrodynamic characteristics of flow oscillation in a contracting and expanding passage subject to vibration. The behaviors of steady and unsteady flow fields under different conditions were investigated. The results show that axial passage vibration leads to flow oscillation because the vibrating passage causes a change in the fluid velocity field. The recirculatory separation and mainstream regions change periodically. The amplitude of the vibrational velocity and the inlet Reynolds number of the fuel have a considerable influence on flow dynamic behavior.