Micro Droplets Merging by Electrowetting: Lattice Boltzmann Study

Abstract In this paper, the Free Energy Based Lattice Boltzmann (FEB-LB) method which has been recently extended by the author for modeling and simulation of Electrowetting (EW) phenomenon is applied to another application of EW, i.e., droplets merging. The obtained results ware compared against experimental data and the results show good accuracy of the numerical simulation

Multi-objective configuration of an intelligent parking lot and combined hydrogen, heat and power (IPL-CHHP) based microgrid

Recently, financial issues have been considered as the main aspects of microgrid (MG) evaluation in the literature. In this study, the optimal configuration of the MG has been calculated by presenting a reliability-constrained optimization model. In this optimization approach, the MG units are considered in full available state and random outage state through the planning horizon. To model a proposed MG in details, its uncertainties are formulated in the main function. A combination of Latin hypercube sampling (LHS) algorithm and K-means clustering algorithm is applied to generate all uncertainties. The proposed model simultaneously optimizes two objectives, namely, economic costs and emission performance. Time of use (TOU) based demand response (DR) program has been employed for optimal management of the demand side. At first, the bi-objective function is converted to a sequence of single-objective constrained problems by employing ε-constraints. All Pareto front solutions are obtained by utilizing GAMS for solving the developed mixed-integer linear programming (MILP) model. To make a trade-off among solutions, the max-min fuzzy decision-making method has been used. Due to the positive effect of the DR program on the configuring problem, the total emission and economic costs of MG have been reduced up to 4.01% and 1.72%, respectively.</p

Wettability alterations and magnetic field effects on the nucleation of magnetic nanofluids: a molecular dynamics simulation

In this study, the effects of surface wettability and nanoparticle concentration on boiling of ferrofluids were investigated with the application of magnetic field using molecular dynamics simulations. Liquid argon was considered as the base fluid with the use of Lennard-Jones fluid model. Two different surfaces (hydrophilic with contact angle of 40.5 degrees and hydrophobic with contact angle of 130.6 degrees) were taken into consideration to investigate the effect of nanoparticle presence on bubble formation over a uniformly heated wall. According to the obtained results, vapor film formation and nucleation depend on the interfacial wettability of nanoparticles and substrate. Compared to the pure liquid, film boiling does not easily happen in the ferrofluid containing hydrophilic nano particles, while it is easy to have vapor film in the nanofluid with hydrophobic nanoparticles. It was found that the momentum change due to external magnetic field dramatically alters the evaporation mechanism, resulting in lower liquid film temperature

Risk-Constrained Optimal Chiller Loading Strategy Using Information Gap Decision Theory

This paper presents a novel framework for economic cooling load dispatch in conventional water-cooled chillers. Moreover, information gap decision theory (IGDT) is applied to the optimal chiller loading (OCL) problem to find the optimum operating point of the test system in three decision-making modes: (a) risk-neutral approach, (b) risk-aversion or robustness approach, and (c) risk-taker or opportunistic approach. In the robustness mode of the IGDT-based OCL problem, the system operator enters a desired energy cost value in order to find the most appropriate loading points for the chillers so that the total electricity procurement cost over the study horizon is smaller than or equal to this critical value. Meanwhile, the cooling load increase is maximized to the highest possible level to find the most robust performance of the benchmark grid with respect to the overestimated load. Similarly, the risk-taker optimization method finds the on/off status and the partial load ratio (PLR) of the chillers in order to keep the total energy cost as low as the given cost function. In addition, the minimum value of cooling load decrease can be found while satisfying the refrigeration capacity of the chiller and the load-generation balance constraint. Thus, a mixed-integer non-linear programming problem is solved using the branch and reduce optimization (BARON) tool of the generalized algebraic mathematical modeling system (GAMS) for a five-chiller plant, to demonstrate that IGDT is able to find a good solution in robustness/risk-taker OCL problem

Numerical investigation of TiO2 and MWCNTs turbine meter oil nanofluids: Flow and hydrodynamic properties

International audienceThe main aim of the present study is to evaluate the influence of multi-walled carbon nanotubes (MWCNTs) and TiO2 nanoparticles (NPs) on lubricant and fluid flow within natural gas turbine meters. In light of this purpose, disparate concentration of TiO2 NPs (0.1, 0.2, and 0.3 wt%), various volume flow rates 0.14, 0.35, and 0.12 were employed for experimental analyses. In the facet of simulation, Gambit software version 2. 4. 6 to mesh oil pathway and Fluent software version for solving the equations were utilized. It was revealed that the pressure drop in the presence of nanoparticles was increased. Moreover, there was an increase in pressure drop value with raising the NPs concentration; for instance, the pressure drop value of MWCNTs-containing nanofluids at the volume flow rate of 0.35 cm enhanced from 92.72 Pa to 94.64 Pa as the NPs concentration raised from 0.1 to 0.3. Furthermore, modeling outcomes corroborated the uptrend in pressure drop value by increasing the volume flow rate and reported the maximum pressure drop value of 0.12 . On the other hand, the numerical results revealed that the friction coefficient is directly and inversely proportional to NPs concentration and the volume flow rates, sequentially. Additionally, with increasing the volume flow rate, the entrance length increased, and reaching the developed state was delayed. It is worth noting as the final finding of this study that increasing the NPs concentration resulted in decreasing the entrance length and the fast reaching of the developed state

The influence of nano filter elements on pressure drop and pollutant elimination efficiency in town border stations

Abstract Natural gas stands as the most ecologically sustainable fossil fuel, constituting nearly 25% of worldwide primary energy utilization and experiencing rapid expansion. This article offers an extensive comparative analysis of nano filter elements, focusing on pressure drop and pollutant removal efficiency. The primary goal was to assess the superior performance of nano filter elements and their suitability as an alternative for Town Border Station (TBS). The research encompassed a six-month examination period, involving routine pressure assessments, structural examinations, and particle characterization of the filter elements. The results revealed that nano filters showed better performance in adsorbing aluminum than conventional filters, possibly due to their cartridge composition. Nano filters contained phosphorus, sulfur, and copper, while conventional filters lacked these elements. The disparity can be attributed to the finer mesh of the nano filter, capturing smaller pollutants. Although the nano filter had minimal silicon, the conventional filter showed some, posing concerns. Despite having 19 extra pleats, the nano filter maintained gas flow pressure while capturing more particles than the conventional filter