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Replacing control valves in the inlet lines of oil transmission stations with hydropower plants can be a logical solution to convert energy losses into useful power. In this regard, this paper carried out an experimental and numerical investigation to study the feasibility of applying a pump as turbine in a hydropower system and its performance on the oil transmission lines. An experimental platform, comprising a tank, hydropower, centrifugal pump, electromotor, and measuring instruments, was constructed. An external gear pump was employed regarding the high working pressure of the system, maximally 80 bar, as an actuator of the centrifugal pump. By comparing the efficiency of the electropump with the hydropower-driven pump, it was observed that maximum efficiency, approximately 20.6%, occurred when the pump reached its best efficiency point. Furthermore, based on experiments on hydropower-driven pump under different inlet pressures, an optimal point was observed for the system. This issue enhanced the system's efficiency by 19% as the flow rate increased by 1.9 L/s in the inlet pressure of 80 bar. According to the results, as the flow rate increases, there is a descending trend in outlet pressure. Besides this, there is an optimum condition for the maximum efficiency of hydropower plants and this crucial point should be determined by experimental or numerical studies to reach maximum performance. Furthermore, extracted values of power from the computational fluid dynamics model were compared with the experiments with less than 8% error in most cases. Therefore, a correlation was introduced for the prediction of power based on effective parameters of outlet pressure and volumetric flow rate for the off-design condition in each inlet pressure with roughly 2% error.

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Liposomes are one of the most attractive particles in different industries, especially pharmaceutical applications. The main reasons for such a desire for liposomes are non-toxicity, small size, the ability to encapsulate and carry biological components, and finally biocompatibility and biodegradability. The present study aims to simulate the active electrohydrodynamic-based micromixer for the high-throughput formation of nanoscale liposomes. The micromixer consists of two inlets for DI water and one inlet for ethanol with lipid particles. Two configurations of asymmetric electrodes namely longitudinal and the array of electrodes were introduced and examined. Electrodes were placed at the bottom of the mixer and a DC electrical field was applied to them. Generated chaotic advection inside the microchannel by the electrical field and consequently increasing surface-to-volume ratio is the main reason for the increase in the formation of liposomes. These configurations of electrodes cause liposome formation occurs at very low voltages which is the most advantage of the proposed micromixer. The Taguchi method as a statistical method of design of experiment (DOE) was utilized to reduce the number of required simulations. The simulations showed that case 6 had the best mixing index of 58.6% among the studied models. Also, according to the DOE results, the best possible design was found and simulated and a mixing index of 74.3% which has a 5.3% error in comparison to the predicted results.