Flow and heat transfer analysis of the microfluidic thermal camouflage film based on bionic structure

Abstract

With the rapid advancement of infrared (IR) detection techniques, the importance of thermal camouflage technology has become increasingly prominent. Inspired by spider webs and honeycombs, microfluidic thermal camouflage films based on two bionic structures are proposed to IR cloak targets by circulating microfluidics in the film. The film displays an adaptive thermal camouflage effect by automatically adjusting the microfluid temperature. Microcavity and microchannel are used as the main internal structure of camouflage film. To compare the thermal camouflage performance of two corresponding bionic structures, heat transfer and fluid flow mechanisms are analyzed. The structure and working principle of the film are introduced, and the testing system is developed to explore the flow and heat transfer characteristics of the bionic spider web micro-channel film and honeycomb cell film. The comparison reveals that the honeycomb cell film's temperature distribution uniformity and heat transfer performance are better than the spider web micro-channel film's, which is suitable for thermal camouflage. Considering the influence of the liquid low-velocity stagnation zone on the camouflage performance, rounded corners of the honeycomb cell are designed to improve the fluid flow properties, and the relationship between the corner radius and the heat transfer characteristics is further investigated. Finally, the honeycomb cell film's parameters are optimized by orthogonal tests, and the optimal solution enhances the thermal camouflage performance. The results show that the film has a good stealth effect, which is expected to motivate the further application of bionic structures in the military field.