Heat Pipe Plate Thermal Conductivity Apparatus And The Wood Thermal Properties

In the research of fire, the heat properties of combustible substance is very important to the study of occurrence and spread of fire. Wood is a kind of typical combustible substance. So it is significant to research the measurement of the wood heat conductivity.In this paper, the research backgroud of this project was briefly introduced. And the current situation of the research of materials' heat properties, wood s' heat properties and plate equipment measuring materials' heat properties was also introduced.After researching those existed plant equipments measuring heat conductivity, a new type of equipment—heat pipe plant equipment was designed and made, according to relative national standards of China. This equipment took advantage of the heat transfer characteristic of heat pipe. In designing the equipment, an equal temperature plate with heat pipe is the maily designed part. By applying the soft of ANSYS to compute the temperature distribution of this plate, suck a plate was designed. In this paper, the analysis of the computing result of simulated temperature distribution in wood sample by using the soft of ANSYS showed that the measurement of heat conductivity with the designed equipment accorded with the theory of one-dimension steady heat conduction. Then a test system involving the equipment was set up.In this research, the across-grain and the along-grain samples of broad leaf and conifer, the samples of redpine and larch of different moisture content, and the samples of different grain were measured by heat pipe plant equipment. Their heat conductivities in temperature range from 35°C to 85°C were obtained.A calculation model was set up which simulates temperature distribution in wood sample. This model was resolved out by the software of ANSYS. The heat conductivity of wood was furtherly modified by this model.The rules of the heat conductivity varying with temperature, moisture content and wood' s grain was given. There were conclusions as follow: in the temperature range from room temperature to 100°C, the heat conductivity of wood increases with the increasing temperature. At 70°C~80°C, the heat conductivity reaches a peak, and then its value decreases while temperature grows. At the same temperature, the higher moisture content of wood was, the bigger the heat conductivity of wood was. As for one wood, the heat conductivity of across grain sample is 1.8~2 times that of along grain sample.