This study investigates the in-orbit liquid hydrogen management capability of screen channel tanks in cryogenic propulsion systems by developing a three-dimensional multiphysics model that integrates filling ratios (5%-50%) and microgravity disturbances(10^-3 g). The competition mechanism between capillary and inertial forces, as well as the fluid retention stability during tank reorientation, was systematically analyzed. The key findings include the following. The fluid retention capability was attributed to the structural synergy between liquid collection channels and tank walls, ensuring continuous liquid coverage at the channel inlets under all operating conditions. At low filling ratios, surface tension dominated the phase distribution with a quasi-static interfacial evolution. Increased filling enhanced inertial forces, inducing phase oscillations via momentum transport. The directional sensitivity analysis revealed that bottom acceleration induced the largest centroid depression, top acceleration had a minimal impact on the relative centroid height, and lateral disturbances caused larger centroid oscillation amplitudes and higher frequencies than oblique lateral disturbances.