Composite Phase Change Materials (PCMs) incorporated with metal foams are promising candidates for thermal management for space exploration. However, void cavities are generated as a result of the volume change of PCM during the melting process, introducing a resistance to heat transfer due to the low thermal conductivity of the void. In this work, the effects of void cavity distribution on the conduction-dominated melting of composite PCMs under microgravity conditions are studied by a two-dimensional pore-scale lattice Boltzmann method, in which a microstructural description of the metal foam is experimentally characterized with the help of X-ray micro-Computed Tomography. Two typical distribution patterns of void cavities are analsed and computed performance is compared (1) a near-wall void cavity, and (2) randomly distributed void cavities. The evolutions of temperature distributions and melting interfaces are compared, and the average liquid fraction and energy stored per width are deduced to describe the energy storage performance. Moreover, the influence of the volume fraction of void cavities is investigated by comparing temperature distributions and energy storage performances of composite PCMs with four different volume fractions of void cavities (0%, 3.7%, 7.6%, 15.2%). After introducing void cavities, the energy stored per width is reduced by 5.7%, 12.3% and 20.2% for randomly distributed void cavities when volume fraction of void cavities is 3.7%, 7.6%, and 15.2%, respectively, and reduced by 42.2%, 64.1% and 79.7% for the near-wall void cavity, respectively. This work initiates the study of the effects of void cavity distribution on composite PCMs, which will stimulate work on structural optimization of thermal management systems.

包含金属泡沫的复合相变材料（PCM）是用于空间探索的热管理的有希望的候选者。但是，由于熔融过程中PCM的体积变化而产生空隙腔，由于空隙的低导热性而引入了对热传递的阻力。在这项工作中，通过二维孔尺度格子Boltzmann方法研究了空孔分布对复合材料PCM在微重力条件下以传导为主的熔化的影响，其中通过对金属泡沫的微观结构描述进行了实验表征。 X射线计算机断层扫描的帮助。分析了两种典型的空隙腔分布模式，并比较了计算的性能（1）近壁空隙腔和（2）随机分布的空隙腔。比较了温度分布和熔化界面的演变，推导了平均液体分数和每宽度存储的能量来描述能量存储性能。此外，通过比较具有四种不同的孔隙率（0％，3.7％，7.6％，15.2％）的复合PCM的温度分布和储能性能，研究了孔隙率的影响。引入空洞后，当空洞的体积分数分别为3.7％，7.6％和15.2％时，随机分布的空洞的每宽度存储的能量分别减少5.7％，12.3％和20.2％，并减少42.2％ ，近壁空隙腔分别为64.1％和79.7％。这项工作启动了空洞分布对复合材料PCM的影响的研究，