In recent decade, water has had extensive applications as base and operative fluid in a lot of industrial and medical nanodevices, such as medical nanopumps for injecting drug continuously in vessels. In viewpoint of biological and industrial applications, it is necessary to study flow behavior and transmission of water molecules under various physical conditions in different nanochannels. In this thesis, by means of Molecular Dynamics Simulation method, the influences of wall electrical charge and roughness on liquid water poiseuille flow in nanochannels with smooth, rough, charged and uncharged walls were studied. Water molecules in real (polar) and nonpolar states has been investigated. In this study, with regard to polar physics of water molecules, the influence of electrical charge in walls on water flow has been studied and the results are compared. Despite some studies that assume water molecules as one rigid nonpolar simple sphere (like argon atoms), in this study, water molecules has been simulated with real physics (hydrogens and oxygens polarity, hydrogen bond and bond flexibility). The velocity and density profiles of water are compared, as two useful and significant parameters. Boundary conditions are periodic in x, y and z directions. Simulations are carried out at temperature of 300 K. The water nondimensional density is assumed 0.995 in all nanochannels. It has been observed that wall roughness affects velocity and density profiles, specially near rough regions. Assumption of nonpolar water molecules does not deviate density profile, but it causes a 40% deviations in velocity profiles compared to polar (real) water molecules. Electrical charges on walls vary density and velocity profiles extensively compared to the uncharged wall. The wall roughness reduces the maximum values of density adjacent to the rough wall and its effects on the water density and water velocity are about 20% and 70% of height of channel. Roughness reduces greatly fluid velocity near the rough wall and reduces the average and maximum velocities in the nanochannel. When the roughness width increases, roughness effects on the velocity and density profiles increases too. Enhancing roughness height causes velocity and density profile deviations. These deviations and reductions due to the roughness height, are more serious than effect of increasing roughness width. Keywords : Nanochannel, Molecular Dynamics Simulation, Water, Roughness.
