Analysis of Design Principles of Combustion Dummy SystemRelease time: 2015-04-11 10:58
System composition and design principle The system is mainly composed of a burning dummy, a data acquisition device, a flame generation and control device, a skin heat transfer model and a burn evaluation model, and a system centralized control and application software platform. The design principle is to simulate the thermal exposure process of the human body in the burning flame and test the change of the surface temperature of the dummy. It is estimated that the second and third degree burns of the skin and the percentage of total burn area may be caused. The worse the flame retardancy protection performance.
The combustion dummy researched and retrieved relevant information at home and abroad. Non-metal materials were used to make the combustion dummy body. The flame duration of the clothing test is generally 4 s. The surface of the dummy may need to withstand a combustion flame up to 300 ℃. Therefore, the dummy body The material must have good thermal stability under the short-term combustion flame above 300 ℃, and can withstand the harsh fire environment; the response of the sensor placed on the surface of the dummy to the combustion flame should be close to the human skin's response to the combustion flame; data The acquisition and processing device can quickly collect dummy surface sensor data.
According to the above design requirements, the dummy body is analyzed by comparing the physical properties of high temperature resistant materials. Polyimide with the highest temperature resistance level, the best mechanical properties, dielectric properties and corrosion resistance is selected as the main body of the burning dummy body. According to the appearance characteristics of the dummy model, the dummy body model is manufactured according to the following process: synthetic polyimide → cured resin material → making molds of human anatomy and high temperature molding → vacuum curing → surface treatment.
Dummy surface heat sensor The function of the dummy skin surface heat sensor is to sense the heat level of the human skin exposed to the fire environment, and predict the degree of burns that may occur on the skin. The thermal sensors used abroad are mainly TPP copper sheet heat flow sensor, adiabatic copper sheet sensor and embedded thermocouple sensor. Of these three types of sensors, adiabatic copper sensors are the most reliable thermal sensors. Experiments show that the adiabatic copper sheet sensor is similar to the TPP copper sheet heat flow meter sensor, with stable readings, fast response, wide range, and good repeatability. At the same time, the sensor volume is smaller than the TPP sensor, occupying less space and mass than the TPP copper sheet heat flow meter. Much more. In high heat environments, the average response speed of embedded thermocouple sensors is slower than that of adiabatic copper sensors. To this end, the research team developed a thermally insulated copper sheet sensor. The copper sheet has a diameter of 1 cm and a thickness of 0.16 cm. The brazing process was used to connect the copper sheet to a K-type thermocouple with a wire diameter of 0.2 mm, and the measurement accuracy reached 0.2 ° C.
The sensor layout takes into account factors such as the area of the dummy, data collection, and calculation of burn evaluation. A total of 120 thermally insulated copper sheet sensors are evenly distributed on the surface of the dummy. When installing the sensor, use a milling cutter to drill holes according to the diameter and depth of the copper sheet to ensure that the sensor surface and the China Textile Leader · 2011 No. 9 139 www.texleader.com.cn Test and Standard Cooperation, the distribution of sensors is even.
Data acquisition device research The data acquisition device mainly completes the processing of 120 thermocouple temperature signals on the surface of the dummy. In order to ensure the synchronization and high-speed acquisition of 120 temperature signals, 20 data acquisition and processing units are designed. Each data acquisition and processing unit is controlled by the main CPU, AD acquisition circuit, real-time clock circuit, power supply circuit, and thermocouple temperature.
Research on flame generation and control device The flame generation and control device mainly generates the combustion flame required for the test of clothing flame retardant protective performance. Including fuel selection, gas transmission pipeline design and burner, etc.
Comparison and analysis of fuel selection Common physical and chemical properties of clean and combustible gases. Propane has a wide range of sources and forms water vapor and carbon dioxide after combustion. It is an environmentally friendly fuel, and has a high calorific value, low boiling point, and good safety. Cold North Laboratories used it, so the fuel for the test system was selected as propane.
More about Burning Dummy System : http://airulm17.com/productlist/list-5-1.html
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