Study On Liquid Sloshing With Small Amplitude Considering Capillary Effect

As the developing of aerospace engineering, spacecrafts bring more and more propellant and liquid charge, on the other hand the attitude keeping and maneuvering are required to be more and more accurate, so the liquid sloshing on spacecraft needs to be studied deeply. From the perspective of aerospace engineering, this thesis studys the liquid sloshing with small amplitude considering capillary effect by theoretical , numerical and experimental methods.In the part of theoretical research the equation and boundary conditions of liquid sloshing with small amplitude considering capillary effect are derived in a new way . The damping theory of liquid sloshing is summarized and developed, new methods of calculation the energy dissipation at contact line and surfactant are proposed. The relationship of characteristic parameters and sloshing frequency , damping in two special case is studied by demensional ananlysis method, some useful results are obtained.In the part of numerical research the FEM modal analysis method of liquid small amplitude sloshing considering capillary effect is studied systematically. According to the different application objects the study is composed of two parts. One is the FEM using boundary conditions without capillary effect. In this case the calculation of frequcies and modals doesn't consider capillary effect, but the calculation of damping considers it. The numerical method of this part has been used in the slohing modeling of a Chinese large satellite successfully. The other part of numercal research is the FEM using boundary conditions with capillary effect. In this case the calculation of frequencies, modal and damping all take capillary effect into account. Because differete contact line boundary conditons make the numerical method different, the pin-end, free-end and wetting boundary conditions of contact line are dealt with separately. The accurate calculation of surfactant dissipation is also consider in this thesis.In the part of experimental research the small amplitude liquid sloshing in a cylindrical container with hemisphere bottom and the nonlinear effect of liquid freely sloshing in a hemisphere container are studied. The experiment results prove the effectiveness of the FEM modal analysis method and show some interesting nonlinear phenomenon.