Influence of microadditive of carbon dioxide on the kinetics of boiling-up of superheated n-pentane

Abstract

The effect of a low-boiling impurity (CO2 gas <1.5% mol) on the kinetics of boiling-up of superheated n-pentane in a vertical glass tube have been studied by high-speed video (2050 fps). The method of continuous pressure decrease from 2.00 to 0.10 MPa (in the temperature range of 100.2-145.1 °C), as well as the method of measuring the lifetimes of superheated liquids at 0.10 MPa (90.2-134.1 °C) have been used. The inner surface of the tube has two visible defects, one of which defines the boundary of the attainable superheat. After degassing the system, the defects of tube cease to play an appreciable role, the active centers are redistributed. The temperature of the attainable superheat increases from the initial value by 20 °C in tests with gas and by 10 °C in subsequent tests without it. The result obtained may be related to physical gas adsorption on the glass surface during the process of evacuation of the system.