关键词: 散热模型, 安全性, 防护服, 数学建模, 仿真模拟

Abstract: In recent years, with the rapid development of the manufacturing industry, a large number of new technologies and new equipment have been used, and the labor group of high-temperature operation has also been increasingly large. The high temperature working environment is harsh, and the high ambient temperature will cause the skin on the human surface to be damaged by high temperature contact. Thermal protective clothing can greatly protect workers in high temperature environments. Heat dissipation is an important factor to be considered in the design and operation of thermal protective clothing. At present, the evaluation of heat dissipation mainly relies on a large number of experimental tests, which cannot be repeated and costs a lot of money. Establishing the mathematical model of heat dissipation of thermal protective clothing in high temperature environment can be used to design thermal protective clothing with better heat dissipation effect in a short research and development period, but the heat dissipation model of the relationship among the external environment, fabric layer and skin has not been established so far.
This paper studied the heat dissipation of protective clothing under high temperature and hot conditions. Based on Fourier heat conduction law, heat conduction equation and other theories, the whole mathematical model of heat conduction and heat dissipation from the environment through the protective clothing fabric layer to the dummy skin was constructed by using the micro-element method, and the temperature change diagram of each layer and interface of the thermal protective clothing with time was drawn during the whole simulated heat dissipation process. The results of model simulation and prediction were verified by actual measurement. At the room temperature of 60℃, the simulation of the outermost layer of protective clothing, that is, the left boundary, reached stability at 59.52 ℃, the second layer of protective clothing reached stability at 59.11 ℃, the third layer of protective clothing reached stability at 58.2 ℃, the fourth layer of protective clothing reached stability at 53.72 ℃, and the skin layer reached stability at 43.71 ℃. It can be concluded that with the increase of the thickness of protective clothing, the skin temperature will gradually decrease, and the air layer has an obvious cooling and heat dissipation effect. In the verification experiment, the temperature sensor DS18B20 was used at 60℃ for a thermostatic dummy with the same fabric condition and the same body temperature, and the digital signal showed that the skin temperature of the dummy was 43.99 ℃. Compared with the predicted temperature of 43.71 ℃ under the same conditions, the error was less than 0.5 ℃. When the experimental room temperature was adjusted to 75 ℃, the measured skin temperature of the dummy was finally stable at 48.08 ℃, and the overall temperature change trend was almost consistent with the model, so it was concluded that the established model was highly accurate. The reason for the error is that as long as only the drying model is considered and the wet transfer is not considered, the experiment dummy does not evaporate sweat, so the error is smaller and it is more reasonable to use the drying model.
Based on the results of simulation and experimental verification in this paper, it can be concluded that the established heat dissipation model of thermal protective clothing in high temperature environment has high accuracy, which has referencial significance for reasonable evaluation of the heat dissipation protection effect of thermal protective clothing.

Key words: heat dissipation model, safety, protective clothing, mathematical modeling, simulation model