Papers by Keyword: Thermal Diffusion Coefficient

Abstract: In order to obtain the critical temperatures of energetic materials thermal reaction in different scales, a multi-scale thermal reaction test system has been developed. In this experiment, the measurement method of thermal diffusivity of energetic materials under test conditions is added. Based on the measured thermal diffusivity in thermal reaction test, activation energy and pre exponential factor measured in laboratory. The critical temperatures of thermal reaction in different scales of DINA are calculated, the calculation results are verified by two different scale thermal reaction tests, and the test results are in good agreement with the calculation results. According to the above calculation method, the critical temperature of thermal reaction of DINA under actual process conditions is obtained; it provides the basis of safety data for enterprise safety production.

Abstract: Based on the calculation formulas of heat treatment temperature field of the narrow strip spot of laser beam passing a scanning rotating mirror, the effect of scanning frequency on temperature field was analyzed in this study, and the math model of the temperature field with scanning frequency was derived applying the superposing principle of the temperature field. The value simulation and figures description were given. The relationship between scanning frequency and temperature distribution was studied, and the best extent of frequency was given for carbon steel laser quenching with laser rotating mirror. The value simulation shows that the higher the scanning frequency is, the more evenly distributed the temperature field gets. At a certain laser power and a certain length of laser scanning line spot, for non-melting laser heat treatment under the spot, a maximum thickness of the high- temperature layer can be get at some certain scanning frequency range which depends on thermal diffusion coefficient of the material.