喷气发动机中的紊流旋涡与仿生学

 现代喷气发动机结构已相当复杂,但其性能仍有许多不能令人满意之处,如沿流路压力损失大、部件效率低、压气机容易失速喘振、燃烧室容易过热震荡、再点火高度低、稳定工作范围窄等。本文讨论紊流旋涡现象,给出新推导的紊流动量方程,仿自然生态,提出减少旋涡损失,利用旋涡功能的设想,引出一些值得深入研究的问题。

TURBULENT VORTICES AND BIONICS IN TURBOJET

The construction of a modern turbojet is rather complex, but its performance still has many dissatisfactions, viz. great pressure losses along the flow path, low component efficiencies, narrow stable operating range, proneness of the compressor to stall and surge, difficulty in high-altitude relighting, frequent occurrence of overheating and oscillations in combustors. The authors consider that all the above drawbacks are closely related to turbulent vortices, which occur almost everywhere within and around a turbojet. The generation, development and decay of vortices have profound mutual effects with the surrounding flow. In aerodynamic design an endeavour must be made to reduce vortex losses and exploit vertex capabilities. There are some interesting peculiar phenomena in a turbulent vortex flow, such as orderly-coherent flow pattern, interniittency and energy-inversion unconformable to the Kolmogoroff theory of energy spectrum. The traditional isotropic turbulence and statistical treatment cannot explain the above phenomena. The co-author has discovered that viscous dissipation and dispersion effects should be considered simultaneously and Burger's and the K-dV equations have to be mixed up to obtain a canonical equation:According to this concept two new momentum equations of turbulent flow are derived:Sample computations of a tail vortex flow and an orderly-coherent flow pattern have been performed with success. The authors suggest some ideas about morphological simulation which may alleviate the vortex evils and utilize the vortex characteristics.