Bulletin of the American Physical Society
75th Annual Meeting of the Division of Fluid Dynamics
Volume 67, Number 19
Sunday–Tuesday, November 20–22, 2022; Indiana Convention Center, Indianapolis, Indiana.
Session T13: Industrial Applications: General |
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Chair: Kamran Alba, University of Houston Room: 140 |
Monday, November 21, 2022 4:10PM - 4:23PM |
T13.00001: Investigating fluid flow through a choke valve Kamran Alba, Harsa Mitra, Trevor Gabel, Rodolfo Ostilla Monico, Frank Koeck, Dan Williams Flow within a control valve is complex, particularly for choke types with multiple fluid entries. Despite their abundant use in industry, there is lack of fundamental fluid dynamics understanding of such valves. Failure through e.g. flow-induced vibration remains a common problem. Through academia-industry collaboration, fluid flow through an actual choke valve is investigated. Integrated Computational Fluid Dynamics (CFD) simulations and Particle Image Velocimetry (PIV) experiments have been used to study valve current under various flow rates and choking conditions. Close agreement is found between the two methods. Velocity, vorticity, pressure, temperature, and density contours are presented across different three-dimensional planes inside the valve. At low valve opening with few contributing flow streams, the analysis points to the formation of a specific, consistent structure established upon head-on collision of the incoming jets within the valve, becoming more complex at higher valve openings where multiple flow streams are engaged. Signal processing in the form of Fast Fourier Transform (FFT), autocorrelation, and continuous wavelet transform is conducted to identify dominant modes of vortex shedding frequency leading to potentially destructive vibration. |
Monday, November 21, 2022 4:23PM - 4:36PM |
T13.00002: Data-driven optimisation of coiled tube reactors via computational fluid dynamics Nausheen Basha, Thomas Savage, Jonathan McDonough, Antonio Del Rio Chanona, Omar K Matar Performance optimisation via data-driven methods is a promising approach to minimise computational effort. In this research we demonstrate the application of a data-driven optimisation technique coupled with CFD to enhance the plug flow performance in a coiled tube reactor subjected to oscillatory flows at highly laminar flow conditions (at least as low as Re=10). We apply Bayesian optimisation techniques based on Gaussian processes to build a surrogate model which is iteratively updated using OpenFOAM simulations evaluated through the PyFoam library. We run transient CFD simulations using the ScalarTransportFoam solver, where a tracer is injected into the water working fluid for a fixed coil geometry to produce a residence time distribution (RTD). We explore the parameter space of Reynolds number (10–50), oscillation amplitude (1–8 mm), and oscillation frequency (2–8 Hz) to find the narrowest RTD, corresponding to optimal plug flow under the laminar flow conditions. We also study the resulting vortex structures to further understand the optimal plug flow performance conditions to guide potential future reactor designs. We expect this low-cost integrated modelling approach to be easily applicable to a wide range of industrial mixers to identify opportunities for performance improvement. |
Monday, November 21, 2022 4:36PM - 4:49PM |
T13.00003: Characterization of Flow Structures in the Upper Cavity of a Rotary Compressor Jun Chen, Puyuan Wu As hundreds of millions of Air conditioning (AC) systems are produced each year, and many use rotary compressors as heat pumps, optimizing the flow inside the rotary compressor to improve its reliability and efficiency becomes a key issue. However, the flow in a rotary compressor is extremely complicated due to the complex internal structures’ geometry and high-speed moving parts. The present work studies the flow field above the rotor/stator in a rotary compressor and two major effects are identified. One is the swirling jet produced by the high-speed rotating rotor. Another is the rotating disk effect induced by the top of the high-speed rotating rotor. The CFD results, validated by experiments, show an inner recirculation zone above the rotor that creates a downward velocity component above the rotor and an outer circulation zone above the stator. With the CFD results and the experimental observations, identified is the transport path of oil droplets in the rotary compressor’s upper cavity. This discovery helps to reduce the lubricant oil escaping from the compressor. |
Monday, November 21, 2022 4:49PM - 5:02PM |
T13.00004: Geometrical optimization of a rocking bioreactor for efficient mixing and oxygen transport Radu Cimpeanu, Minki Kim, Daniel Harris Rocking or wave-mixed bioreactors have recently been proposed as a promising innovation for the production of cultivated meat. Unlike other types of bioreactors, they are disposable, require low operating expenses, and are simple to scale up. However the performance of the rocking bioreactor is not well characterized due to a wide range of geometrical and operating parameters, and its short history in market. In the present study we quantitatively evaluate mixing within a rocking bioreactor with different geometries and operating conditions based on an implementation in the Basilisk open-source platform. We use the second-order finite volume Navier-Stokes solver and a volume-of-fluid interface reconstruction method to accurately resolve the highly nonlinear fluid motion. We additionally solve the advection-diffusion equation for soluble tracers to compute the degree of mixing. In particular, we investigate the dependence of mixing times on the aspect ratio in simplified elliptical geometries. Our results are expected to provide guidelines for designing optimized bioreactors for next generation cultivated meat industry design pipelines. |
Monday, November 21, 2022 5:02PM - 5:15PM |
T13.00005: On the hydrostatic limit for thin film flow with applications to thermosyphons. Vivek Kumar, Muhammad R Rizwanur, Prashant R Waghmare, Morris R Flynn Thermosyphons are passive heat exchangers that combine phase change and flow in achieving rates of heat transfer well in excess of those due to conduction. The flow of liquid that develops within a moderately-inclined thermosyphon is driven primarily by the hydrostatic force associated with the elevation difference between the deep liquid pool within the (raised) condenser vs the shallow liquid pool at evaporator. Such considerations ostensibly favor a deep liquid pool in the condenser, however, any gain of axial (convective) heat transfer may be offset by a corresponding decrease of radial heat transfer by conduction. Finding the optimum balance between these two competing effects is a surprisingly rich problem that requires from a theoretical perspective the application of the Navier Stokes equations in conjunction with thermodynamical considerations. For prescribed working fluid, inclination angle and heat load, the theoretical model in question can predicts the liquid fill ratio required to maximize thermosyphon performance. We juxtapose our results with those associated with a capillarity driven heat pipe. On the basis of this comparison we can predict, with particular reference to the liquid flow, parametric combinations where one vs the other engineering design is favored |
Monday, November 21, 2022 5:15PM - 5:28PM |
T13.00006: Numerical simulation of surfactant-laden emulsion formation in a stirred vessel Fuyue Liang, Juan Pablo Valdes, Lyes Kahouadji, Seungwon Shin, Jalel Chergui, Damir Juric, Omar K Matar The present study aims to establish the transparent interplay among interfacial deformation, surfactant transport, and the underlying flow structure inside a cylindrical stirred vessel equipped with a pitched blade turbine. Massively parallel, three-dimensional, interface-tracking, large eddy simulations of O/W emulsification are deployed to provide detailed, realistic visualization of the intricate interfacial dynamics coupled to the turbulent flow fields, from the onset of impeller rotation through to the attainment of a dynamic steady state. This study investigates the effect of surfactant elasticity (the sensitivity of interfacial tension to the surfactant concentration), the Biot number (the ratio of characteristic desorptive to convective time scale), and Marangoni stresses. Allied to this, the transient drop counts, and their size distribution have been tracked. In particular, the simulations have demonstrated that the presence of surfactant is associated with interfacial rigidification, suppression of end-pinching, and promotion of tip-streaming. The interfacial dynamics in the surfactant-laden system alters the evolution of drop count and their size distribution, where the appearance of the first dispersed drop occurs earlier and a larger number of relatively small drops are observed in comparison to their surfactant-free counterparts carried out in our previous work. |
Monday, November 21, 2022 5:28PM - 5:41PM |
T13.00007: Pressure drop and filtration efficiency of a ceramic filter and its optimal design Sehyeong Oh, Dong Sik Yang, Hyun Chul Lee, Hyuk Jae Kwon, Sang Min Ji, Su Keun Kuk, Min Seok Koo, Jaehee Chang, Jhoon Kim The pressure drop and the filtration efficiency of a ceramic filter (CF) are investigated. The ceramic filter is a monolithic honeycomb-like structure with a porosity. To analyze the flow characteristics of the CF, the Navier-Stokes-Brinkman equations are numerically solved. The numerical results indicate that the pressure drop of the CF is mainly due to the viscous drags at the channel surfaces and the Darcy's drag at the porous ceramic wall. Also, we find that the pressure drop at the entrance and the pressure recovery at the exit are relatively small. To predict the pressure drops of the CFs, we use a one-dimensional pressure drop model (Konstandopoulos & Johnson 1989). Also, the filtration theory of a spherical packed bed combined with the pressure drop model is used for the prediction of the filtration efficiency of the CF. The predicted pressure drops and filtration efficiencies are in a good agreement with the numerical and experimental results, respectively. Finally, we find the optimal shape of a CF that provides a large filtration efficiency with minimum pressure drop by using the models and an optimizer. The present method may be a guideline for the design of a CF with high performance. |
Monday, November 21, 2022 5:41PM - 5:54PM Author not Attending |
T13.00008: Computational design of optimal nozzle shape for liquid metal jetting using scaling analysis and multiphase flow simulation Jongmin Seo, Svyatoslav Korneev, Christoforos Somarakis, Morad Behandish, Adrian Lew We present physics-driven nozzle design rules to achieve fast and stable jetting in drop-on-demand liquid metal 3D printing. The design rules are based on scaling laws that capture the change of meniscus oscillation relaxation time with geometric parameters of the nozzle's inner profile. The nozzle geometry is parameterized by bulk volume, cross-sectional area, and circumferential area of the inner channel. We employed the Navier-Stokes equation and the Stokes boundary layer theory to derive a hypothesis for scaling rule of viscous dissipation at the meniscus of the nozzle outlet. The scaling of relaxation time of the meniscus is inversely proportional to the circumferential surface area to the volume of the nozzle. The proposed scaling rule is demonstrated by multiphase flow simulations. Using OpenFOAM multiphase flow solver, we performed several simulations of oscillatory dynamics of multiphase interface between liquid metal (Al) and Argon gas under a pressure gradient across the nozzle and the surface tension. Informed by our analytical and numerical investigations, we present several design concepts with parameterized classes of shapes for optimal performance of 3D printing nozzle. |
Monday, November 21, 2022 5:54PM - 6:07PM |
T13.00009: Direct numerical simulations of the dispersion dynamics of liquid-liquid surfactant-laden flows in static mixers Juan Pablo Valdes, Fuyue Liang, Lyes Kahouadji, Seungwon Shin, Jalel Chergui, Damir Juric, Omar K Matar This study focuses on the effect of adding surfactants to enhance dispersion performance for manufacturing applications. We implement three-dimensional direct numerical simulations with a hybrid front-tracking/level-set interface capturing algorithm to provide a deep insight into the relevant physical mechanisms that govern fundamental processes during the dispersion (i.e., droplet deformation, breakage and coalescence). In this work, a 2-element SMX static mixer is set-up operating in a laminar regime under three main scenarios: 1) insoluble surfactant trapped at the interface between phases; 2) insoluble and Marangoni-free surfactant, where tangential stresses arising from surfactant concentration gradients are removed; and 3) fully-soluble surfactant, where there is mass exchange between the interface and the dispersed phase. For Cases 1 and 2, the surfactant’s influence on the surface tension is analysed through the elasticity parameter and the Marangoni effects are isolated. For Case 3, the surfactant’s adsorption and desorption capabilities are investigated via parameters reflecing the ratio of desorption to inertia, ratio of adsorption to desorption and ratio of bulk vs. interfacial surfactant concentration and contrasted against the clean and insoluble cases. A larger number of droplets are generated in the presence of surfactants but the dispersion process follows a different mechanism compared to the clean case, where a delay in the formation of droplets is seen. This is attributed to the concentration gradients acting on the initial ligaments, which set back early interfacial instabilities but prompt a larger number of daughter droplets once breakage occurs via Rayleigh-Plateau instability. The initial interfacial concentration of surfactant was observed to heavily influence the early droplet deformation and thus its subsequent breakage mechanism and daughter drop count. |
Monday, November 21, 2022 6:07PM - 6:20PM |
T13.00010: Homogenization of turbulent flows inside industrial environments: an application to the curing of Carbon Fiber Reinforced Polymers Luca Banetta, Luca Cattarossi, Andrea Mignone, Daniele L Marchisio, Daniela Tordella This work proposes a study of turbulence homogenization inside large industrial environments, with a first application to the curing treatment of Carbon-Fiber-Reinforced Polymers, which are composite materials widely spread in the aerospace industry. The state-of-the-art design of these machineries causes a highly anisotropic turbulent flow, that leads to an heterogeneous heat exchange between the air and the mold containing the material to be treated, which causes the curing procedure to be inhomogeneous. |
Monday, November 21, 2022 6:20PM - 6:33PM |
T13.00011: Microdroplet capture by a tunable dielectrophoretic (DEP) filter Harunori N Yoshikawa, Arkadeep Datta, Ranjan Ganguly Dielectrophoretic (DEP) collection of water droplets, 5 to a few tens of microns in diameter, transported in an air free-stream is investigated through a numerical simulation in view of applications in air purification technology. The droplet transport-dynamics are modelled as passive individual particles using a Lagrangian scheme that takes into account the interplay of inertia, viscous, DEP and random Brownian forces on the dispersed phase. The DEP filter is assumed to consist of an array of cylindrical model fibers, which also serve as electrodes where three-phase voltage is imposed. The filtering efficiency is determined through statistical analysis of the simulation results. The effects of the applied electric voltage on the filter efficiency are examined for different droplet diameters and inter-fiber distances and for a wide range of air velocity. The optimum frequencies at which the droplet capture efficiency attains its maximum value are also determined. It is shown that these frequencies are well correlated by a single dimensionless number representing the residence time of particles in the vicinity of the filter. Findings of the study leads to the design bases of active filtration systems for critical healthcare enclosures and advanced face masks. |
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