Dynamic Analysis And Parameter Optimization Design Of Fluid-filled Pipes System

In spacecraft fuel cell system, a complete satellite power supply system is constituted of various fluid- filled pipes, and the supply of fuel and oxidizer for the satellite power system is implemented. Due to the fact that the state of the work component is disturbed or switched inevitably during the system working, and thus results in the unsteady flow of the fluid filling the pipes. This unsteady flow has a great influence on the work elements in the pipeline system, such as the vibration of the pipeline system, deteriorating system working environment, which will grea tly reduce the reliability of the spacecraft fuel cell system, even cause pipes blowout, system failure and/or other serious engineering accidents. Therefore, it is of significantly theoretical meaning and engineering value to improve the system reliability by studying the dynamic problems of fluid- filled pipe system and optimizing the fluid- filled pipe system.In the paper, dynamic problems related to the fluid- filled system are investigated by following aspects:(1) The finite element models of bend and c urved pipe are established by means of FEM code ADINA, and pipeline dynamic properties with Fluid-Structure Interaction(FSI) are researched. Modal analysis is conducted for pipe wall thicknesses, pipe diameter, angle of the bend corner, the radius of curvature and the elastic modulus of materials, and the effects on the dynamic property of the system are exhibited.(2) The finite element model of curved pipe with unsteady flow is completed and the dynamic response of the curved pressure pipes is studied. The influences of various parameters on the displacement of maximum response are obtained by dynamic response analysis for the radius of curvature, wall thickness, pipe diameter and elastic modulus.(3) The dynamic optimization model of curved pipe is established. In the model, optimal objective is to minimize the maximum dynamic displacement response, constraint is the fundamental frequency which is greater than the engineering design requirements, and design variables are curvature radius, pipe diameter a nd wall thickness. The objective function and constraint function are fitted explicitly by the response surface methodology of minimizing the maximum difference, and the optimization model is solved by sequential quadratic programming method based on the MATLAB platform. The design solutions for improving the system’s properties of the fluid-filled pipe are obtained accordingly.In this paper, the results meet expectations, and offer theoretical reference to design reliable, safe and excellent space fuel cell system as well.