The Influence Compensation Methods of Non-Identical Conditions of Heat Exchange in the Measuring Cells of Differential Calorimeter

Abstract

The article is devoted to improving the accuracy of the vapori­zation heat measurement by differential calorimeters of synchronous thermal analysis. The evaporation heat measurement by the method of synchronous thermal analysis is fraught with difficulties. Non-identical conditions of heat exchange are installed in measuring cells of differential calorimeter (fig.1) due to the decreasing temperature of the sample surface because of evaporation. If the effect of this non-identity will not be taken into account when processing the data, the result will contain an additional error. We were considered the different methods for determining the vaporization heat which take into account the influence non-identical heat exchange conditions in the cells. The first method is based on the analytical determination of the temperature difference bet­ween the surface of the sample and the cell-referent. The second method allows to measure the temperature difference between the surface of the sample and cell-referent experimentally. Advantages and disadvantages of each method are considered in detail. Also presented the new design of calorimeter (fig 2), which is able to rea­lize in practice the new experimental method for determining the vaporization heat.

Keywords

• differential calorimeter, heat exchange conditions, heat of vaporization