Thermal effects of direct-liquid-cooled split disk laser. (June 2022)

• Record Type: Journal Article
• Authors: Yang, Huomu
• Is Part Of: Optics & laser technology. Volume 150(2022)
• Publication Date: 2022-06
• Subjects: Direct-liquid-cooled split disk laser -- Thermal effects -- Longitudinal temperature rise -- Thermal stress; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2022.107945
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: The direct-liquid-cooled split disk laser is attractive in high power lasers. Thermal effects, the main barrier of solid-state laser to reach high power, high beam quality and high efficiency laser output, are studied in this work. The analytical solutions both of temperature field and of thermal stress in the gain medium of direct-liquid-cooled split disk laser are obtained. To validate the analytical solution, thermal stress obtained from analytical solution is compared with that of the finite element simulation. The optimized coolant, coolant velocity and heat load density are also discussed. This work is significant for the direct-liquid-cooled split disk laser both in theory and in engineering application. Abstract: Thermal effects of direct-liquid-cooled split disk laser are analytically solved and discussed. Based on the hydrodynamics and the heat transfer theory, the convective heat transfer coefficient is obtained from empirical correlations, and an analytical solution is adopted to describe the temperature field in the disk gain medium with consideration of longitudinal coolant temperature rise. The expression of thermal stress in the disk gain medium is also derived with the minimum energy principle. To validate the analytical solutions of the temperature and of the thermal stress, finite element simulations are performed, and the results reveal that the solutions with analytical method are consistent with that of finite element simulation. Based on the derived analytical solutions, the cooling capacities of FC-40, HT-110, D2 O and pure water are compared, the longitudinal coolant temperature variation and its induced thermal stress are studied. Furthermore, the optimized coolant velocity and the heat load density were obtained with the consideration of 373 K gasification point of the coolant, which is significant for the direct-liquid-cooled split disk laser both in theory and in engineering application.