Topology Optimization Of Fluid-solid Conjugate Heat Transfer Structure

For fluid-solid conjugate heat transfer structure,heat transfer efficiency not only depends on thermal properties of fluid and solid materials,but also be affected by the shape of channel and flow characteristics,like velocity.The optimization of fluid-solid conjugate heat transfer structure was restricted to size or shape optimization until thermal fluid topology optimization is fully developed,which can enhance cooling capacity and optimization efficiency dramatically.Although most real flow conditions are turbulent,using turbulence model for topology optimization requires a large amount of calculation,which dissatisfies the requirements of rapid simulation and low turnaround time during the conceptual design phase.A suitable substitute model for turbulence flow should be chosen for topology optimization.In this paper,we first approximate the flow as an inviscid one by a Darcy potential flow model to realize the topology optimization of cooling channel,while the permeability setting and pressure drop constraint setting methods are also studied.Another method that using Navier-Stokes equations to describe flow is also applied to design cooling channel.Two methods are compared from different aspects(for example,applicability,convergence speed and optimized results),reaching the conclusion that using Darcy model as a substitute model for turbulence flow in the concept design phase is more suitable and of guiding significance for engineering practice.On the basis of former work and comparison,we propose a method to realize the topology optimization of a pseudo 3D fluid-solid conjugate heat transfer structure based on scramjet active cooling system by using Darcy potential flow model to describe the flow.Adding the heat source on the base plate beneath the cooling channel,the out-of-plane heat transfer depends on the material distribution.By the interpolation between convective heat transfer coefficient and the conductive heat transfer resistance,the out-of-plane heat transfer term can represent both the conductive heat transfer from the base plate into the solid area and the convective heat transfer to the fluid in the channel.Comparing to the traditional regular configurations,the optimized cooling channel configurations have been significantly improved in reducing the average temperature and flow loss.