An engineering extension of scanning electron beam thermal assessment technology to curved surfaces

Scanning electron beam thermal assessment can create a heat flux field with designable peaks and gradients to serve as a thermal assessment environment, supporting the iterative design of thermal protection materials and structures for hypersonic vehicles. By considering the relationship between the conversion efficiency of electron beam kinetic energy into material internal energy and the electron beam incidence angle, the scanning electron beam thermal assessment is extended to curved surfaces. For both typical curved surface structures of the convex and concave hemispheres, nonuniform target heat flux fields with Gaussian distributions are designed, and electron beam heating experiments are conducted. The experimental steady-state temperatures at characteristic points are compared with the simulation results. Additionally, the effect of beam spot deformation on the reconstruction of the target heat flux field is discussed. The theoretical results show that the target heat flux fields can be reconstructed within a relative deviation of 3%, and the experimental and simulated results of the steady-state temperatures show good agreement, with deviations of less than 1%. These results validate the feasibility of the curved surface extension method for the scanning electron beam thermal assessment. The beam spot deformation during scanning can increase the reconstruction deviation of the target heat flux field to approximately 17%, but it has a minimal effect on the heating results of the sample, with an induced temperature deviation of approximately 1%. This work extends the scanning electron beam thermal assessment from planar to curved surfaces, significantly enhancing its applicability for thermal protection performance analysis