Validation of a 1D Transient Simulation Model of a Multistage Axial Compressor

An unsteady one-dimensional dynamic model has been developed at Georgia Tech to investigate the impact of stage characteristics as well as load distribution on the compression and expansion waves that develop prior to a surge event in a multistage axial compressor. In the developed model, each of the blade rows is replaced by a duct of varying cross-sectional area with force and work source terms. The source terms model the force and energy imparted by a blade row to the working fluid. The modeling assumes the flow to be inviscid, unsteady, compressible and axisymmetric. While rotating stall cannot be explicitly modeled in a 1D mean-line method, the effect of rotating stall can be captured by a judicious choice of source terms that reflects the loss of pumping capability of a stage. Conservation of mass, momentum and energy are applied to an elemental control volume resulting in one-dimensional quasi-linear Euler system of equations. A non-uniform grid and the second-order central difference Kurganov-Tadmor (KT) scheme are used to discretize the one-dimensional computational domain. The resulting ODEs are solved with an explicit second order Runge-Kutta solver. A throttle schedule is used to introduce perturbations at a selected operating condition in order to study flow oscillations that can lead to a stall event. The current study is aimed at validation of the developed flow solver using an industrial compressor database. Further, the current study is aimed at understanding the interaction between the stages with regards to pressure oscillations leading to stall.