Study On The Water Entrainment Capabilities For The Inclined Product Oil Pipeline

In this paper, the water entrainment capabilities of diesel oil for the inclined pipeline were experimentally studied, and the main work and conclusions were shown as follows:Firstly, a new laboratory experimental loop was designed and built to do the research on the two-phase flow of oil and water, and it could be used to study the water entrainment capabilities of diesel oil in the inclined tube as well.Secondly, the test section of the loop was made up of two kinds of transparent pipes: one was theΦ15mm glass tube and the other was theΦ25mm reinforced plastic hose. The two-phase flow pattern and the water entrainment process of diesel oil were observed and videoed, meanwhile, the thickness, distribution, convergence and separation of the residual water at the bottom of the tube were analyzed, by virtue of the two transparent tubes. The test results showed that, the upstream part of the water body was a little thinner than that of the downstream part. Under small flow rate, the oil-water two-phase flow was laminar with smooth interface between the two fluids; while, under large flow rate, the oil and water changed into wave flow with fluctuant interface; furthermore, once the flow rate increased even greater, the water would be scoured into smaller pieces. The water entrainment process for the inclined product oil pipeline was accompanied with continuous convergence and separation of the water masses.Thirdly, the test section of the loop was made up ofΦ27mm andΦ41mm galvanized steel pipes, so that the water entrainment process for the real product oil pipeline could be simulated and studied. By measuring the water output through different sampling valves along the slope, the water entrainment capabilities of diesel oil was quantified properly, and the effects of flow rate, pipe diameter and residual water amount on the water entrainment capabilities were analyzed respectively. The test results showed that, the lager the flow rate was, the farther the water would be taken. The way and effect of the water entrainment process of diesel oil was greatly dependent upon the relative thickness of water layer. When the water layer was relatively thin, the residual water was mainly dragged upwards by shear stress on the oil-water interface, and the water output grew gradually with the increase of flow rate. When the water layer was relatively thick, the residual water was mainly pushed upwards by pressure, and the water output grew rapidly with the increase of flow rate. Moreover, the water mass at the bottom would be scoured into small pieces, which were prone to be taken away from the pipe wall and ran downstream directly, in the case of large flow rate and water amount.Besides, on the basis of theoretical analysis, it was suggested that the effective shear rate for pipe flow should be used as the similarity criteria, considering the engineering application of the water entrainment test data.