Numerical Simulation And Aberration Analysis Of Heat-Fluid-Solid Interconnection Process In Solid-state Laser

The thermal effects and wavefront aberrations of solid-state lasers severely constrain the further improvement of the output power and performance of solid-state lasers,which is one of the main problems that researchers pay attention to in recent years.The immersed direct liquidcooled solid-state laser,with its excellent structural design of the gain module,can efficiently reduce the thermal effect and wavefront aberration.Once this design was proposed,it had received extensive attention from scholars at home and abroad.However,the research on the thermal effect and wavefront aberration of solid-state lasers is currently limited to single field problems and seldom covers the interaction between multiple fields.Therefore,it is very important to study the influence of various design parameters and operating parameters on the thermal effect and wave aberration of lasers.In this paper,we use the research method of numerical simulation,and establish a three-dimensional coupled thermo-hydro-mechanical model and an optical path difference analysis model of the immersed direct liquid-cooled solidstate lasers in order to study the thermal effect and wavefront aberration of solid-state lasers.Firstly,according to the computational fluid mechanics method,we choose a suitable turbulence model,establish the microchannel fluid flow model,and investigate the influence of the microchannel height,the relative roughness and the type of the cooling medium on the change of the flow state.The model parameters of the gain module are determined on the basis of the relevant influence law and the previous research results of the research group.Secondly,we choose suitable coupled thermo-hydro-mechanical modeling method.Unidirectional and bidirectional coupling methods are respectively adopted to establish the two dimensional coupled thermo-hydro-mechanical model of the gain module.Compared two coupling methods,it is found that their results are almost the same.The unidirectional coupling method is the better choice in consideration of the calculation cost.Finally,we establish the three-dimensional coupled thermo-hydro-mechanical model and the optical path difference analysis model of the immersed direct liquid-cooled solid-state laser,and discuss the influence of the flow Reynolds number and the chip heat load on the thermal effect and the optical path difference of the gain module.The study shows that the optical path difference distribution in the gain module is not uniform.When Re=2600,the maximum optical path difference is 1.1546 um,the minimum value is-0.0294 um,and the PV value is 1.1840 um.In the laminar flow state,the PV value increases with the increase of the flow Reynolds number,and the position of the valley remains while the position of peak is shifted;in the turbulent flow state,the valley value decreases with the increase of the flow Reynolds number,the peak and the valley are all shifted,and the direction is opposite to the moving direction in the laminar state.The PV value of the optical path difference increases with the increase of the chip heat load,while the positions of the peak and the vally are not affected by the change of the chip heat load.The research results in this paper are of guiding significance to the research and design of the gain module of immersed direct liquid-cooled solid-state laser and the determination of the optimal operating parameters of lasers.