Thermal management and simulation studies of a 200-kW calorimetric dummy load for HE11 mode at 42?GHz

The objective of this study is to design a calorimetric dummy load (CDL) containing an efficient cooling mechanism to absorb maximum power of 200 kW at 42 ± 0.2 GHz frequency for maximum duration of 3 seconds. The design is suited for microwave power propagating in HE₁₁ mode. High microwave power is generally measured and characterized by CDL, which is designed to suit the exiting modes of the gyrotron. In the current project, the output mode of the gyrotron in TE₀₃ is converted to a Gaussian HE₁₁ mode with help of series of mode converters. This study highlights thermal analysis and simulation studies using ANSYS computational fluid dynamics analysis for water coolant passing through helical teflon tubing. Analytical calculations for thermal management of water coolant are also carried out and compared with the simulation studies. A defocusing convex mirror has been designed using a quasi-optical approach. Material selection of the defocusing mirror, based on cost-effectiveness, transient thermal analysis, and microwave power absorption in the skin depth of the material, has been carried out. Finally, a comparison of analytical calculation and simulation studies has been carried out.