八面体桁架结构在内冷通道中的流动传热特性研究

In order to explore the possibility of application of the octet truss structure in internal cooling channel in hot components of aeroengine，and understand its flow and heat transfer characteristics，the investigations both on effective thermal conductivity of an octet truss element and fluid structure and heat transfer performance of octet truss array structure have been carried out by exploiting methods of theoretical derivation and three-dimensional numerical simulation，respectively. First of all，the correlation of effective thermal conductivity which considers nodal effects has been derived out for an octet truss element，moreover，its effectiveness has been validated by comparing with numerical results. Subsequently，a series of full-detailed three-dimensional calculations has been carried out for octet truss array structure，in which the flow structure and temperature distribution have been analyzed，furthermore，the variation of friction factor and heat transfer coefficient with Reynolds number have been obtained. Finally，in consideration of heat transfer performance of the octet truss structure，the Nusselt numbers for octet truss structures with different porosity have been compared under equal pumping power. As a result，a reasonable range of dimensionless diameter which leads to an excellent heat transfer performance has been proposed as 0.07~0.08，whose corresponding porosity ranges in 0.872~0.841. The reason may be concluded that the heat transfer rate increases with the decrease of porosity，i.e.，the increase of the solidity. However，when the porosity decreases to below 84.1%，the friction factor increases drastically，leading to the decrease of overall heat transfer efficiency. The proposal of the utilization of the octet truss in internal cooling channel in hot end components of aeroengine considers the advantages both of higher efficient cooling and mechanical performance. The result is helpful to provide theoretical support for application in practical engineering.