Based on the physical model in COMSOL Multiphysics package, a 3D model of a radiator has been developed. Using the finite element method, a number of numerical simulations were carried out. The results of the temperature distribution on the radiator surface were obtained. Numerical methods are subject to some errors, so it is important to validate the results. In order to verify the correctness of the numerical model, a test stand equipped with a radiator, a heating resistor, a fan and a FLIR SC7600 thermal imaging camera was constructed. The heating resistor allowed the regulation of the heat flux by changing the DC voltage. Thermograms were obtained showing the temperature distribution on the radiator surface. It has been found out that it is possible to use thermovision in laboratory tests to validate numerical models. The validation of the numerical results was carried out by comparing the results of the numerical simulations with temperature measurements in the real conditions. Therefore, both techniques can be methodically used when designing new equipment.