This paper focuses on the stability of capillary forced flow.In space,open capillary channels are widely used as the liquid and gas separation devices to manage liquid positioning and transportation.Surface collapse happens when the flow rate exceeds the critical value,leading to a failure of propellant management.Knowledge of flow rate limitation is of great significance in design and optimization of propellant management devices(PMDs).However,the capillary flow rate limitation in an asymmetry channel has not been studied yet in the literature.In this paper,by introducing an equivalent angle to convert the asymmetry corner to a symmetry one,the one-dimensional theoretical model is developed.The flow rate limitation can then be investigated as a function of the channel geometry as well as liquid property based on the model.Comparisons between the asymmetry and symmetry channels bring forth the characteristics of the two kinds of channels,and demonstrate good accordance between the new advanced model and the existing one in the literature.This theoretical model can provide valuable reference for PMD designers. This paper focuses on the stability of capillary forced flow. In space, open capillary channels are widely used as the liquid and gas separation devices to manage liquid positioning and transportation. of propellant management. Knowledge of flow rate limitation of great significance in design and optimization of propellant management devices (PMDs) .However, the capillary flow rate limitation in an asymmetry channel has not been studied yet in the literature. In this paper, by introducing an equivalent angle to convert the asymmetry corner to a symmetry one, the one-dimensional theoretical model is developed. flow rate limitation can then be investigated as a function of the channel geometry as well as liquid property based on the model. Comparisons between the asymmetry and symmetry channels bring forth the characteristics of the two kinds of channels, and demonstrate good good between the new advanced model and the existing one in the literature.This theoretical model can provide valuable reference for PMD designers.