Hydrodynamic simulation of draw solution flow fields in a submerged Forward Osmosis membrane module

Simulation of flow field and particle trajectory of radio frequency inductively coupled plasma spheroidization

Recently, the lattice Boltzmann method (LBM) is being applied in turbomachinery field, regarded as a good candidate for tool of flow simulation as well as aerodynamic sound analysis. For better prediction of broadband noise with high frequecy, which is generally generated in high Reynolds number flows, not only high grid resolution is required to capture very small eddies of the sound source inside the turbulent boundary layer, but also the computation of acoustic field is often needed. In such case, the direct simulation of flow field and acoustic field is straight-forward and effective. However, the computational cost becomes extremely expensive. Moreover, for low Mach number flows the compressible Navier-Stokes simulation not only requires high-order scheme which is unsuitable for parallel computation, but also suffers from stiff problem. LBM is suitable for such simulation thanks to its advantages. In the present study, a large-scale numerical simulation of flow field around a half-ducted propeller fan is conducted with LBM, and its result is validated by comparing with the experimental result.

This paper presents the results of a numerical simulation of the time-averaged inviscid flow field through the blade rows of a multiblade row turboprop configuration. The governing equations are outlined along with a discussion of the solution procedure and coding strategy. Numerical results obtained from a simulation of the flow field through a modern high-speed turboprop will be shown.

This paper presents the results of three-dimensional and time-accurate Computational Fluid Dynamics (CFD) simulations of the flow field around the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor. The 3-D, unsteady, parallel, finite volume flow solver, PUMA2, is used for the simulations. The solutions are obtained using unstructured moving grids rotating with the turbine blades. Three different flow cases with different wind speeds and wind yaw angles are investigated: 7 m/s with 0◦ yaw (pre-stall case I), 7 m/s with 30◦ yaw (prestall, yawed case II), and 15 m/s with 0◦ yaw (post-stall case III). Results from the inviscid simulations for these three cases and comparisons with the experimental data are presented. Some information on the current work in progress towards Large Eddy Simulations (LES), including details about the viscous grid and the implementation of wall-functions, are also discussed. The inviscid results show that the flow is attached for cases I and II, with the latter having an asymmetrical wake structure, whereas there is massive separation over the entire blade span in case III. There are considerable spanwise pressure variations in addition to the chordwise variations, in all three cases. Comparisons of sectional pressure coefficient distributions with experimental data show good agreement. These threedimensional and time-accurate CFD results can be used for the far-field noise predictions based on the Ffowcs Williams Hawkings method (FWH), which can provide a first-principles prediction of both the noise and the underlying turbulent flow that generates the noise, in the context of the wind turbine application.

This paper presents the results of three-dimensional and time-accurate, parallel Computational Fluid Dynamics (CFD) simulations of the flow field around a Horizontal Axis Wind Turbine (HAWT) rotor. Large Eddy Simulation (LES) methodology with an instantaneous loglaw wall model is used for the viscous computations. The 3-D, unsteady, parallel, finite volume flow solver, PUMA2, is used for the simulations. The solutions are obtained using unstructured moving grids rotating with the turbine blades. Three different flow cases with different wind speeds and wind yaw angles are investigated. Results for these three cases and comparisons with the experimental data are presented.

This paper adopts three different grids to conduct numerical simulation of flow field around an angle member by CFD. The two-dimensional incompressible Navier-Stokes equation is solved. The pressure velocity coupling adopts the SIMPLE algorithm and the pressure discretization adopts the standard algorithm. Both the momentum equation and turbulence model adopt the second-order windward scheme, and the time term adopts the second-order implicit scheme. The aerodynamic coefficients of angle member and the flow field are obtained by different grids, and through comparison, it is found that the grid mode has a very small impact on the CFD results, and the differences between different grid modes can be ignored. In respect of CFD simulation of flow field around angle member in transmission tower, it is recommended to adopt the partitioned structured grids and the partitioned mixed grids in order to enhance the simulation ability of the grid under multiple working conditions. If the angle member is irregularly shaped, the partitioned mixed grids are preferred.

Evaluation of draw solutions and commercially available forward osmosis membrane modules for wastewater reclamation at pilot scale

Although forward osmosis (FO) membranes have shown great promise for many applications, there are few studies attempting to create a systematization of the testing conditions at a pilot scale for FO membrane modules. To address this issue, hollow fiber forward osmosis (HFFO) membrane modules with different performances (water flux and solute rejection) have been investigated at different operating conditions. Various draw and feed flow rates, draw solute types and concentrations, transmembrane pressures, temperatures, and operation modes have been studied using two model feed solutions—deionized water and artificial seawater. The significance of the operational conditions in the FO process was attributed to a dominant role of concentration polarization (CP) effects, where the selected draw solute and draw concentration had the biggest impact on membrane performance due to internal CP. Additionally, the rejection of the HFFO membranes using three model solutes (caffeine, niacin, and urea) were determined under both FO and reverse osmosis (RO) conditions with the same process recovery. FO rejections had an increase of 2% for caffeine, 19% for niacin, and 740% for urea compared to the RO rejections. Overall, this is the first extensive study of commercially available inside-out HFFO membrane modules.

Method of Computational Fluid Dynamics (CFD) was applied to numerical simulation of gases' thermal and flow fields of Metal Organic Chemical Vapor Deposition (MOCVD) reactor which grows high-efficiency three-junction GaInP/GaAs/Ge tandem solar cells. Virtual Reality (VR) technology was applied to visualization of numerical simulation of gas's thermal and flow fields of MOCVD reactor. The results of numerical simulation provide optimization of processing parameters in MOCVD reactor under a certain conditions, providing rational suggestion for optimization design in size of the substrate in the reactor. The results of visualization truly and intuitively display distributing situation of gas's temperature field and velocity field in MOCVD reactor, providing further optimizations of processing parameters of GaInP thin film grown by MOCVD with theoretical basis.

Hybrid membrane system for desalination and wastewater treatment : Integrating forward osmosis and low pressure reverse osmosis

Forward osmosis for concentrating lithium-enriched brine: From membrane performance to system design

Numerical simulation of flow field inside abrasive water jet nozzle on steady, turbulence, two-phase flow conditions was carried out based on FLUENT. The main geometric parameters of abrasive water jet nozzle were analyzed. The results show that the smaller the contraction angle a of the focusing tube, the better flow field inside abrasive water jet nozzle is. Also smaller contraction angle avoids abrasive gathering at the entrance of the focusing tube. The smaller the outlet diameter of focusing tube, the greater velocity of the abrasive can be obtained. On the other hand, the smaller the outlet diameter of focusing tube is, the smaller negative pressure inside the mixing chamber exists. Consequently abrasive inhalation is not good. Outlet diameter of focusing tube should be in the range of 3 times of the jewel orifice. The results show also that the length of the focusing tube has significant effect on the outlet velocity of abrasive. In order to achieve maximum speed of abrasive, the length of cylinder part of focusing tube should be in the range of 30 times of the outlet diameter. Simulation of flow field inside abrasive water jet nozzle and analysis of parameters of the focusing tube provide basis in design of nozzle for abrasive water jet.

Dong, H.; Huang, P.; Sun, Z.; Li, Z., and Chong, L., 2020. Numerical simulation of local scour and flow field around pipelines. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research, Special Issue No. 111, pp. 272–278. Coconut Creek (Florida), ISSN 0749-0208.Numerical simulations were conducted where both local scour below pipelines and flow fields around pipelines occur. The evolution, shape, and scale of local scouring at pipelines under different flow velocities and pipeline layouts were calculated. The research area is Huibieyang Sea of Zhejiang, China, where large numbers of submarine pipelines have been laid. Results show that typical accumulations of sand waves cannot form behind the pipelines in this study area due to their fine sediment size. Data from field observations at the water depth where the pipelines are located were collected in this study, on the basis of which preliminary analysis was made on the stability of the seabed and local scouring in the research area in recent years.

Research on simulation of gun muzzle flow field empowered by artificial intelligence

Taking the flow field, temperature, pressure and stress of the three-way catalytic converter of automotive gasoline engine as the objective constraints, the multi-disciplinary optimization design objective function of the three-way catalytic converter of automotive gasoline engine is established. The flow field simulation, stress field simulation, temperature field simulation and pressure field simulation results of the three-way catalytic converter of automotive gasoline engine are obtained by using the fuzzy neural network. An agent model is established to optimize the proposed adaptive chaotic particle swarm optimization algorithm, and the optimal design parameters of three-way catalytic converter for automotive gasoline engine are obtained. The correctness of the research is verified by experiments.