Design And Topology Optimization Of Heat Insulation Structure With Phase Change Materials

The phase change material can absorb or release a large amount of latent heat under the condition of keeping the temperature basically unchanged,to achieve cooling during a short period of high heating power,or to achieve temperature control in a large fluctuating thermal environment.Therefore,phase-change heat is of great significance to the design of aerospace structures that serve in extremely harsh thermal environments.However,commonly used phase change materials(such as paraffin)have low thermal conductivity,which will cause local temperature gradients to be too large,thereby losing the temperature control effect.This article mainly works from two aspects: one is for the integrated thermal protection system with great application potential in the future,the design scheme of integrating phase change material is given,and the heat insulation effect of phase change material is discussed;It is the design goal to improve the internal heat transfer capability of the phase change material,and the topology optimization method of the heat conduction enhancement body of the phase change material is established to give full play to the temperature control ability of the phase change material.The specific research content is as follows:1)Design and optimization of an integrated thermal protection structure containing phase change materials.The integrated thermal protection structure integrates the thermal protection layer and the load-bearing structure,which not only saves space,but also achieves substantial weight reduction.It is a design solution with great application potential.However,due to the high thermal conductivity of materials with high load-bearing capacity,this design has a serious thermal short-circuit effect,and the structure is also prone to local buckling failure under thermal load.To this end,this paper proposes an integrated thermal protection structure design plan containing phase change materials,adding a thin layer of phase change material to absorb the incoming heat,thereby reducing the internal temperature,and passing through the corrugated plate clamp of the web.The core structure design improves the load-bearing capacity of the structure without increasing the weight of the structure.Through the numerical simulation method,the performance of the new scheme is calculated.The results show that the multi-level integrated thermal protection structure design containing phase change materials has better heat insulation and bearing capacity than the original structure.2)Topology optimization design method of phase change material heat conduction enhancement body.Implanting high thermal conductivity materials inside the phase change material is the main way to improve the internal heat transfer capability of the phase change material.At present,the commonly used heat conduction enhancers mainly include metal fins,foams,lattices and other forms.The structural forms of different heat conduction enhancers have a significant impact on their performance improvement.To this end,the text research establishes the topology optimization design method of the phase change material heat conduction enhancement body,in order to find the best high heat conduction path,and give full play to the ability of the phase change material.In the implementation process,a smooth approximate function is used to describe the heat capacity to avoid the numerical instability of the step function to the optimization process;in order to adopt the gradient optimization method,the analytical sensitivity of the design target is derived through the adjoint method expression.Discuss the influence of different design parameters on the topology optimization results,and compare them with the calculation results of the existing transient heat conduction structure topology optimization model.The results show that the design method proposed in this paper can effectively obtain the high-performance thermal conductivity enhancement structure configuration design,but the existing transient heat conduction topology optimization method cannot be obtained,which proves that the method proposed in this paper is very necessary.