Experimental Investigation on the Effect of Sawdust Particles Size on Its Thermal Conductivity

Abstract

The measurement of the thermal conductivity of the sawdust is one of the most difficult techniques due to its uniformed shape, by using this instrument, it gives the ability of measuring the thermal conductivity of the sawdust, without changing its physical properties, during the experiment, as well as, there are no necessity to use the additional materials in form of adhesive materials, that gives an identified shape of the specimen. In this study, wood sawdust is classified into three groups depending on the size of the wood pellets, namely; wo1≥1.18mm, 1.18>wo2>0.6mm and wo3≤0.6mm. To keep out the thermal properties of the sawdust as it is, no mechanical or chemical processes were carried out on sawdust specimens, such as compressing or bonding. The effect of moisture content on the thermal properties of sawdust is eliminated by drying the specimens, the procedure is carried out by heating it up to 100℃ for a 30 min. During this study, it can be seen that the thermal conductivity of all samples is inversely proportional to the working temperature. At a relatively low temperature less than 45℃, it can be said that the first model (wo1) has the lowest thermal conductivity while the differences in the thermal conductivity of the samples are insignificant when the temperature exceed 50℃, therefore; the first model (wo1) represents a good choice for flat plate solar collector insulation because it has the same activity as well as it is light and cheap.