The interior comer flow theory is fundamental for liquid management in space. In this paper, the interior comer flow theory is modified by correction of the curvature and shape parameters based on geometry relationshi...The interior comer flow theory is fundamental for liquid management in space. In this paper, the interior comer flow theory is modified by correction of the curvature and shape parameters based on geometry relationship, so that it can be extended to a wide range of applications including different dihedral angles and contact angles. This modification is validated with the data provided by the references using capillary tube and drop tower. Besides, the errors between the theory and experiment value are analyzed for the case of small viscosity and the long-time flow, finding that the main reason causing the error is the transformation of the flow resistance along the flow path. At last, the theory of interior comer flow is applied to the primary design of the Propellant Management Device in satellite tank, and optimum design of the vanes is given in terms of maximum flow rate.展开更多
Abstract 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. Surfac...Abstract 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.展开更多
A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of t...A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computa- tional Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dim- ensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50975280)the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-08-0149)
文摘The interior comer flow theory is fundamental for liquid management in space. In this paper, the interior comer flow theory is modified by correction of the curvature and shape parameters based on geometry relationship, so that it can be extended to a wide range of applications including different dihedral angles and contact angles. This modification is validated with the data provided by the references using capillary tube and drop tower. Besides, the errors between the theory and experiment value are analyzed for the case of small viscosity and the long-time flow, finding that the main reason causing the error is the transformation of the flow resistance along the flow path. At last, the theory of interior comer flow is applied to the primary design of the Propellant Management Device in satellite tank, and optimum design of the vanes is given in terms of maximum flow rate.
基金supported by the National Natural Science Foundation of China(Nos.50975280 and 61004094)
文摘Abstract 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.
文摘A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computa- tional Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dim- ensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.
