Ultrathin vapor chamber (UTVC) is considered an ideal solution to the heat dissipation problem of aircraft and spacecraft. However, the cooling performance rapidly deteriorates due to the obstruction of the liquid return flow under acceleration overload, posing a serious threat to the safety of the spacecraft. More seriously, few theoretical models can reveal the mechanism of heat transfer under centrifugal conditions, resulting in an increase in the design cost and difficulty of the anti-centrifugal ultrathin vapor chamber (ACUTVC). Herein, two novel ACUTVCs based on the anti-centrifugal wicks were proposed, which were extensively tested and compared with the UTVC based on the traditional wick. Results show that the effective thermal conductivities of the ACUTVCs exceed 1500 W m−1 K−1 even under extreme conditions of a 6 g acceleration, which are about four times that of copper and comparable to commercial graphene films, demonstrating reliable thermal management capability under high-g conditions. The heat transfer mechanisms under different centrifugal conditions were revealed by the theoretical model proposed in this work, with a maximum error of 26.27% compared to the experimental results, showing a good agreement. Model results highlight the potential optimization approaches of wick structures, which may guide the new directions for the design of the ACUTVC.

It is well known that the optical properties of multi-particle phosphor are crucial to the light performance of white light-emitting diodes (LEDs). Note that the optical properties including scattering or absorption properties for a single particle are easy to be calculated. However, due to the large computation considering the complicated re-scattering and re-absorption, it is difficult to calculate the scattering behaviors of the multi-particles. A common method to reduce the computation, which can cause unknown deviations, is to replace the multi-particle scattering properties by using the average scattering data of single particles. In this work, a cluster of multi-phosphor particles are directly simulated by the finite-difference time-domain (FDTD) method. The total scattering data of the cluster was processed as a bulk scattering parameter and imported to the Monte-Carlo ray-tracing (RT) method to realize a large-scale multi-particle scattering calculation. A polynomial mathematical model was built according to the multi-particle scattering data. An experiment was carried out for verifying the accuracy of the method in this work. The mean absolute percentages of the previous method are 1.68, 2.06, and 1.22 times larger than the multi-particle method compared with the experimental curves, respectively.