DETERMINATION OF PRESSURE DROP IN A TWO-PHASE, LIQUID-LIQUID SYSTEM IN A HORIZONTAL PIPELINE THROUGH MATLAB SIMULATION

The pressure drop of the flow inside the pipeline is an important parameter to be
determined before proceeding with the design. This parameter is very important to
pipeline size selection and the design of the downstream facilities. Underestimation
of pressure drop will give a smaller pipe size than required, thus the transportation
capacity will be restricted. In the other hand, overestimation of pressure drop will
cause in oversized pipeline, worse sweeping characteristics, and possible solid
dropout and corrosion issues. The wrong prediction of pressure drop is likely to
occur in a liquid-liquid two phase system which false predictions of interface
configurations are made. A tlat intertace is assumed between the phases which
actually highly applicable for high-density differential system, such as gas-liquid
system under earth condition. However, tor liquid-liquid system with small density
differences or in reduced gravity system, the factor of curvature interface must be
considered. The interface configuration tor liquid-liquid systems can either be tlat,
concave or convex. Hence, to overcome this problem, a model is developed to
calculate pressure drop tor liquid-liquid system that will consider the tactor of
curvature interface between the phases. In this modelling, two-fluid model is used for
prediction of pressure drop and this model is derived to make it applicable tor
stratified tlow system only. The model is developed by using MATLAB
programming and it is tested with tew sets of input data. The calculated pressure
drop from this model is compared with experimental data to check for its reliability.
As a conclusion, it is shown that tlat-shape intertace assumption is not the best
assumption for this prediction. The percentage difference of prediction is very large
when it was compared to experimental data. Curvature intertacial contiguration is
assumed to give best prediction, however, in this project, the curvature interfuce
assumption not give an expected result. This is due to some ambiguity in cross
sectional area and wetted perimeter derivation formula used in this model. Hence,
modification in the correlated function has to be developed to prove that calculation
using the curved interface will give better assumption of pressure drop.