Direct drive valve model for use as an acoustic source in a network model

Direct Drive Valves (DDVs) can be used as acoustic actuators in duct systems when requirements on mechanical or thermal robustness are high, e.g., for the active control of aerodynamic or combustion instabilities. This paper presents a model of a DDV that is used as an active element in an acoustic network model. In acoustic network modelling tools, acoustic sources are often implemented as simple velocity or mass flow boundary conditions. In practice, however, DDVs are not necessarily situated at the boundary of the system and the throughflow depends on the fluctuating pressure drop over the valve. This paper presents an acoustically compact model, based on mass conservation and a time-varying hydraulic resistance. The resistance depends on the fluctuating valve opening. The results are compared to the experiment in terms of acoustic wave transfer function.