Numerical and experimental investigation of the temperature field uniformity in a dual-layer laser thermostatic chamber for ultra-high-temperature calibration.

To enhance the temperature uniformity and stability of the constant-temperature cavity during the static calibration of ultra-high-temperature sensors, this paper proposes a structural design method for a dual-layer temperature-controlled laser thermostatic chamber (LTC) based on laser heating. Using ZEMAX software, laser beam shaping is simulated to achieve energy redistribution from a Gaussian spot to a square uniform spot, thereby improving the spatial distribution characteristics of laser energy at the source. Furthermore, a heat conduction model of the LTC is established using COMSOL Multiphysics to systematically analyze the effects of spot morphology, laser irradiation mode, and thermal insulation structure on the temperature field distribution within the LTC. Simulation results indicate that double-sided symmetric square uniform spot irradiation combined with a graphite felt insulation structure can effectively suppress temperature gradients, reducing the temperature non-uniformity of the LTC to approximately 4.25%. On this basis, an experimental platform for an ultra-high-temperature laser heating static calibration system is constructed. Experimental results show that, under a laser power of 1000 W, the proposed structure achieves a minimum temperature non-uniformity of 4.89% and maintains a steady-state fluctuation of ±5.5∘C at 2100°C. The results demonstrate that the synergistic optimization of beam shaping and the dual-layer temperature control structure can significantly improve the temperature field distribution within the LTC, providing reliable technical support and a theoretical basis for the high-precision static calibration of ultra-high-temperature sensors.