The high pressure loss and low heat transfer efficiency have been plaguing the development of high power fast axial-flow CO2 laser. In order to solve this problem, a special longitudinal vortex generator (LVG), which contains two modified right-angled trapezoid wings and interrupt gap (TMRTW), was proposed. The performance of a single trapezoid winglet (STW) and TMRTW was discussed. Numerical study reveals that compared with STW, the TMRTW has better flow and heat transfer characteristics under the same initialization conditions. Further parametric study indicates that the TMRTW generates vortex. The intensity of this vortex is mainly present in central area. The downstream extension of this vortex is better than that of STW. Especially for the developing of boundary layers, this is beneficial. Hence, the performance of heat transfer for TMRTW is enhanced obviously with Re less than 1200. Compared with STW, the heat transfer for TMRTW is enhanced by 16% under the optimized structure size, with the pressure penalty almost the same.
Two photonic qubits, initially maximally entangled in OAM modes of Hermite-Gaussian HG vortex beam, propagating through non-Kolmogorov turbulence are investigated numerically. The influences of turbulence parameter (i.e., the generalized exponent, the outer scale of turbulence, and the inner scale of turbulence) and OAM values on the entanglement evolution of two photon are investigated and compared with those of the Laguerre-Gaussian (LG) beam. The results indicate that the OAM entanglement to be more robust in turbulence for the higher OAM values, the higher generalized exponent. Moreover, the influence of the turbulence inner scale and outer scale on OAM entanglement can be ignored. The OAM entanglement of HG vortex beam is better than the OAM entanglement of LG beam for resisting the entanglement decoherence of atmosphere turbulence under the same conditions.
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