Impact of pressure variations at inlet and outlet boundaries on aerodynamic performance of multi-stage axial compressor

Flow variations commonly exist in multi-stage turbomachines, strongly impacting the performance of these machines at most times. Quantification of performance impact of flow variations is one of the most attractive topics because it benefits the robust design of turbomachines. Statistical analysis is essential in Uncertainty Quantification (UQ), yet flow computations of multi-stages are expensive. Apart from the efficient UQ methods, a fast performance calculator is another answer to the computational cost decrease of UQ. This paper presents a method for evaluating the performance changes of a multi-stage axial compressor considering pressure variations at both the inlet and outlet boundaries using the time-marching Euler Throughflow Method (TFM). First, the time-marching TFM is introduced to performance prediction of a low-speed axial compressor. The results are verified and validated by comparing with those obtained by a three-dimensional computational fluid dynamics method. Then the direct Monte Carlo simulation is employed to evaluate the changes of adiabatic efficiency, mass flow rate and total pressure ratio at different operation conditions, considering the variations of separated inlet total pressure, outlet static pressure, and the simultaneous variations of these two. Moreover, for the UQ case with simultaneous flow variations, Sobol sensitivity analysis indicates that the interactions between the inlet total pressure and outlet static pressure are strong under the near stall operation condition. Finally, flow solutions are statistically analyzed to reveal the impact mechanisms of uncertainties on the flow field variations and the performance changes of the multi-stage axial compressor, through which the potential robust design is suggested.