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At present, there are few research on thermal effects of objects irradiated by incoherent directional light. Two methods which are experiments and numerical simulation are adopted to study the transient temperature field of the cotton-padded jacket irradiated by incoherent directional light. Firstly, based on 3D transient heat transfer equation, the transient temperature field model of the cotton-padded jacket which are irradiated by incoherent directional light is established. Secondly, when the initial condition, boundary condition and light parameters have already been set, the module of heat transfer in solids which is from the COMSOL Multiphysics 5.5 software is used to calculate the transient temperature field of the cotton-padded jacket. Thirdly, in order to verify the accuracy of numerically calculating results, the experiments which the incoherent directional light irradiates the cotton-padded jacket are done. The infrared images of jacket at different irradiation time are recorded by a long-wave infrared camera. Finally, the temperature fields of the jacket obtained by numerical calculation and experiments are analyzed. The common points between the two results include: the temperature of the jacket increases with the increase of irradiation time; the temperature of the jacket at the light spot center is the higher, while the temperature at the spot edge is lower. The different points between the two results include: at the same irradiation time, the temperature values of the two results are different; when the irradiation time is more than 20 s, the relative error of the two results is less than 10%. The analysis results show that the numerical calculation model of the temperature field of the cotton-padded jacket irradiated by incoherent directional strong light is reliable. The model can be used to numerically calculate the temperature field of different objects irradiated by incoherent directional light under different conditions.
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