ANALYSIS OF VARIOUS FACTORS AFFECTING HYDRAULIC REDUCtion EFFiCiency BY DRAG REDUCING ADDITIVES

Abstract

Background It is known that the injection of small amount of drag reducing additives (DRA) consisting α-polyalphaolefin in the turbulent flow of oil product can significantly reduce the hydraulic resistance of the pipeline. However, the drag reduction efficiency of additives depends on the molecular weight of the polymer, its molecular structure, rheological properties, additive concentration, property of oil products, temperature and other flow conditions. Aims and Objectives Experimental study of the regularities of the influence of these factors and to achieve maximum efficiency of reducing hydraulic resistance. Methods Laboratory testing of solutions of five drag reducing additives with concentrations of 0-60 ppm in two brands of diesel fuel was carried out. The studies were carried out on a disk rheometer in the range of Reynolds number 2·104-1.2·107, temperature 15-25 °C and the time 0-2 h. The analysis of the factors influencing the efficiency of reducing the hydraulic resistance by additives. Results The results showed that the efficiency of reducing the hydraulic resistance increases with an increasing of concentration of additives, the Reynolds number, the length of the molecular chain (molecular weight) and a decreasing viscosity of diesel fuel. In the experiment, it was found out that with increasing temperature to a certain value, the hydraulic efficiency of DRA increases, reaches a maximum value, and then gradually decreases. The duration of the experiment allowed to establish a pattern of reducing the hydraulic efficiency of DRA in the period caused by the degradation (destruction) of polymer macromolecules. The rate of decrease in the hydraulic efficiency of DRA is proportional to the concentration of the additive in the solution.