Session: 11-46-01: Methods and Algorithms in Computational Heat Transfer

Paper Number: 99833

99833 - Fully Coupled Thermal-Fluidic-Structural Topology Optimization of Conformal Fluid Channels for Thermal Management of Structures 

This work presents a fully coupled thermal fluidic structural topology optimization framework (TO) of conformal fluid channels for forced convective thermal management of structures subject to dimensional requirements. Examples of such structures are injection molds and dies for casting, cooling jacket for batteries and CPUs, and aerodynamic parts for jet and rocket engines. Some processes require the working areas to heat up to a target temperature while others benefit from removing the heat away from the working areas. Therefore, an effective thermal management system designed to meet the process-specific requirements is important to ensure part and tool performance. Since heat transfer between the fluid and the structure causes thermal deformation of the structure, the design of such fluid channels involves the consideration of fluid mechanics, heat transfer, and structural mechanics.  The past approaches for the TO of conformal fluid channels, however, have limited applicability to this problem, since they do not consider thermal-structural coupling and hence ignore thermal-structural coupling. To fill the gap, we have developed a TO formulation based on a fully coupled thermal fluidic structural analysis. The formulation is based on Solid Isotropic Material with Penalization (SIMP). Darcy’s law is used to approximate fluid flow velocity through the “gray” material during the optimization to reduce computational effort. Darcy’s law assumes a porous matrix of solid and fluid allowing monolithic formulations of governing material properties interpolation functions. The approximation gives a linear relationship between the fluid flow velocity and the pressure gradient along the flow path. The approximated Darcian flow field is coupled to a convection-diffusion based heat transfer model to obtain the temperature field. The displacement field is computed from thermal expansion coupling using the temperature field. A three-dimensional numerical example on the design of a mold for wind turbine blades demonstrates the formulation can successfully generate the conformal fluid channels that meet the requirements on both temperature distribution and dimensional distortion on the mold surface. An extended formulation is also discussed, where an additional constraint on the local volume in the neighborhood of each design point is introduced. This additional local volume constraint leads to the generation of optimally distributed free-form functionally graded lattices within the structure, enhancing heat exchange between fluid and solid while reducing overall structural weight. A numerical example with the extended formulation demonstrates the ability of the framework to create functionally graded lattice structures while meeting the thermal and structural requirements from the original formulation.

Presenting Author: Heting Fu University of Michigan at Ann Arbor

Presenting Author Biography: Heting Fu is a Ph.D. student at the University of Michigan at Ann Arbor. He is researching on computational design and optimization under the guidance of Professor Kazuhiro Saitou.

Authors:

Heting Fu University of Michigan at Ann Arbor
Kazuhiro Saitou University of Michigan at Ann Arbor
Deng Hao University of Michigan at Ann Arbor