In this paper, a large eddy simulation model (LES) was adopted to analyse the large-scale precessing vortices and energy separation in a Ranque–Hilsch vortex tube. By comparing the time-averaged axial velocity field between the Laser Doppler velocimetry data and the numerical results, the feasibility of the LES model was confirmed. The 2D instant flow field presents two vortex structures of secondary circulation flow at the cold end, and precessing vortices inside the tube. It also reveals two opposite flows in the axial and radial directions, and the precessing vortices formed by the reverse flow turn towards the main flow. Then, the 3D coherent structure inside the vortex tube was obtained by the vortex identification method for the first time. The basic vortex structure inside the vortex tube consists of the vortex body, detached vortex, and fragmentised detached vortex. Through the evolution of the 3D vortex structure, it was found that the detached vortices experienced a life cycle of growth, shedding, fragmenting, and vanishing. Benefitting from the vortex shedding processes, the precessing vortices overcame the adverse radial pressure gradient and drove part of the reverse flow towards the main flow from the low-pressure zone to the high-pressure zone. Through these processes, the vortex core precession that drives the reciprocating motion of the gas parcels near the reverse flow boundary was established, and energy could be transferred from the inner layer to the outer layer through a heat pump cycle.

在本文中，采用大涡模拟模型（LES）分析了Ranque-Hilsch涡管中的大型进动涡和能量分离。通过比较激光多普勒测速仪数据和数值结果之间的时间平均轴向速度场，证实了LES模型的可行性。二维瞬时流场在冷端呈现二次循环流的两个涡旋结构，并在管内产生旋涡。它还显示了在轴向和径向上的两个相反的流，并且由反向流形成的旋进旋涡转向主流。然后，通过涡流识别方法首次获得了涡流管内部的3D相干结构。涡管内部的基本涡结构由涡体，分离涡，和破碎的分离涡。通过3D涡旋结构的演变，发现分离的涡旋经历了生长，脱落，破碎和消失的生命周期。得益于涡流脱落过程，进动涡流克服了不利的径向压力梯度，并将部分逆流从低压区流向主流，流向高压区。通过这些过程，建立了驱动气体包裹在逆流边界附近往复运动的涡旋核心进动，并且能量可以通过热泵循环从内层传递到外层。和消失。得益于涡流脱落过程，进动涡流克服了不利的径向压力梯度，并将部分逆流从低压区流向主流，流向高压区。通过这些过程，建立了驱动气体包裹在逆流边界附近往复运动的涡旋核心进动，并且能量可以通过热泵循环从内层传递到外层。和消失。得益于涡流脱落过程，进动涡流克服了不利的径向压力梯度，并将部分逆流从低压区流向主流，流向高压区。通过这些过程，建立了驱动气体包裹在逆流边界附近往复运动的涡旋核心进动，并且能量可以通过热泵循环从内层传递到外层。