Determining pressure losses in flushing pipelines by two-phase flow

A stream of water is used in flushing ship systems and their elements. To increase the efficiency of the process, a two-phase pulsating flow can be used. This method of flushing intensification brings tangible results, but currently has a number of unsolved problems. One of these problems is the question related to the determination of energy costs for the transportation of a two-phase mixture. The energy costs for transporting the flow depend on the magnitude of pressure losses due to friction and on the orientation of the pipeline sections in space. An attempt was made to estimate the pressure loss during transportation of a mixture of water and air through a flushed pipeline. The main theoretical dependencies are determined: mixture density, velocities of various phases of the flow, volumetric and mass flow rates, mixture flow rate on volumetric and mass water-air content. A theoretical substantiation is given for determining the pressure loss during the movement of a two-phase flushing medium depending on the concentration of the gas (air) phase in the mixture. When determining pressure losses, a homogeneous model of a two-phase mixture was used as the most suitable for the flushing mode with a two-phase pulsating flow. The main calculated dependences for calculating the pressure losses for the transport of a two-phase mixture in horizontal and vertical sections of pipelines of constant internal diameter are determined. The dependence of pressure losses on gas content in horizontal and vertical sections of pipelines has been established. An assessment of the pressure loss during flushing with a two-phase flow in differently oriented sections of ship pipelines was carried out in order to determine the further effectiveness of this flushing method.