Research On Flow Field And Heat Transfer In Silent Discharge CO₂ Laser

Convection cooling silent discharge CO₂ laser is a novel high performance,low cost industrial CO₂ laser,The stability of the flow channel structure and heat transfer performance is higher due to the use of the opposite direction of the convective cooling lateral flow mode.The key structure of the laser channel was optimized to improve the discharge flow field uniformity and obtain high power,high beam quality and stable performance of the laser output.And the heat exchange system of laser has been designed,including the design of vortex generators into the heat transfer.The main research work is as follows:A numerical model of silent discharge CO₂ laser flow structure has been established,based on boundary layer theory and jet flow theory,to optimize the design of the key guiding device laser channel,reduces the pressure loss of flow,reduce the fan load,increasing the volume of traffic,which can improve the laser heat transfer performance and the conversion efficiency.The uniformity of the flow field in the discharge region was increased by 1.9%,the longitudinal uniformity was improved by a factor of 4.5%,and the quality of the laser beam and the stability of the laser power are improved.The graphical user interface of the heat exchanger was established on the Visual Studio platform,based on the basic theoretical formula of heat exchanger,which is convenient for the theoretical design of different structure heat exchangers.And the heat exchanger of the theoretical design was numerical simulated,the difference of simulation results and the theoretical design was small,less than 10%.The heat exchanger system was optimized by the way of theoretical calculation and numerical simulation.The new design model of heat exchanger system slightly improves fan working temperature,and at the same time,the wind machine was still in the normal working temperature range,the heat exchanger structure has been simplified,the overall pressure drop was reduced by 14%.The enhanced heat transfer performance of the rectangular winglet vortex generator was studied,using a open loop wind tunnel experiment platform,and experiments verify the reliability of numerical simulation data.The numerical models of three kinds of vortex generators were built to compare enhanced heat transfer performance of the rectangular,trapezoidal and triangular vortex generators.A new type of double trapezoidal winglet vortex generator was put forward,based on the the trapezoidal winglet vortex generator.The comprehensive heat transfer performance of the double trapezoidal vortex generator is higher than that of single trapezoidal vortex generator in the low Reynolds number,and the heat transfer characteristics are related to the length of the slot,with the increase of Reynolds number,the heat transfer performance is better when the slot length is larger.