Статті в журналах: "Plug Flow Modelling"

1

Wodołażski, Artur, and Adam Smoliński. "Bio-Hydrogen Production in Packed Bed Continuous Plug Flow Reactor—CFD-Multiphase Modelling." Processes 10, no. 10 (September 20, 2022): 1907. http://dx.doi.org/10.3390/pr10101907.

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This research study investigates the modelling and simulation of biomass anaerobic dark fermentation in bio-hydrogen production in a continuous plug flow reactor. A CFD multiphase full transient model in long-term horizons was adopted to model dark fermentation biohydrogen production in continuous mode. Both the continuous discharge of biomass, which prevents the accumulation of solid parts, and the recirculation of the liquid phase ensure constant access to the nutrient solution. The effect of the hydraulic retention time (HRT), pH and the feed rate on the bio-hydrogen yield and production rates were examined in the simulation stage. Metabolite proportions (VFA: acetic, propionic, butyric) constitute important parameters influencing the bio-hydrogen production efficiency. The model of substrate inhibition on bio-hydrogen production from glucose by attached cells of the microorganism T. neapolitana applied to the modelling of the kinetics of bio-hydrogen production was used. The modelling and simulation of a continuous plug flow (bio)reactor in biohydrogen production is an important part of the process design, modelling and optimization of the biological H2 production pathway.

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2

Veluchamy, C., Ajay S. Kalamdhad, and Brandon H. Gilroyed. "Evaluating and modelling of plug flow reactor digesting lignocellulosic corn silage." Fuel 287 (March 2021): 119498. http://dx.doi.org/10.1016/j.fuel.2020.119498.

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3

Yeung, Hoi. "Modelling of service reservoirs." Journal of Hydroinformatics 3, no. 3 (July 1, 2001): 165–72. http://dx.doi.org/10.2166/hydro.2001.0016.

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Service reservoirs were built to provide the dual function of balancing supply with demand and provision of adequate head to maintain pressure throughout the distribution network. Changing demographics in the UK and reducing leakage have led to significant increases in water age and hence increased risk of poor water quality. Computational fluid mechanics has been used to study the behaviour of a range of service reservoirs with a rectangular plan form. Detailed analysis of flow distribution and water age suggests that tanks with horizontal inlets are better mixed when compared with vertical top water level inlets. With increasing length to width ratio, the flow characteristics of tanks with vertical inlets increasingly resemble plug flow. A new multi-channel reactor model was developed to model the recirculations in service reservoirs. This simple model can be used to characterise the flow characteristics of service reservoirs from tracer test results.

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4

Ivanov, E. A., A. S. Klyuyev, A. A. Zharkovskii, and I. O. Borshchev. "Numerical Simulation of Multiphase Flow Structures in Openfoam Software Package." E3S Web of Conferences 320 (2021): 04016. http://dx.doi.org/10.1051/e3sconf/202132004016.

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Numerical simulation of various structures of multiphase flow in the pipe was performed using the OpenFOAM software package. A visual comparison of multiphase flow design structures for separated stratified-wave, plug and annular flow modes with experimental data is presented. For multiphase flow modelling the solver compressibleInterFoam was used. From the results of numerical modelling, it follows that the OpenFOAM software package allows correct prediction of multiphase flow modes in the pipe depending on Reynolds numbers for gas and liquid phases of the flow.

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5

Dócs, Roland, and Krisztián Mátyás Baracza. "A new method of pressure drop modelling in sandstone rocks." Multidiszciplináris tudományok 12, no. 3 (2022): 264–73. http://dx.doi.org/10.35925/j.multi.2022.3.24.

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Production capacity of any hydrocarbon reservoir is the most important question that needs to be answered. This depends on both the obtainable drawdown between the well and reservoir and the petrophysical properties (pore size distribution, wettability properties, saturations etc.) of the porous rock material. Permeability, introduced by Darcy is the parameter describing restrictions present during fluid flow in porous media. Although this method is the one currently accepted and implemented in the industry it has a major flaw because it considers flow in the geometric (total) rather than the effective volume, where it truly develops. During this study a new approach of flow restriction modelling was found, where flow restrictions, measured from sandstone plug samples were compared with the theoretic flow volumes which are equal to the total pore volumes, constructed of steel capillaries of equal diameter. Results show that flow restrictions of incompressible fluids in sandstone can be demonstrated by the new model.

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6

Juanico, Marcelo. "Should Waste Stabilization Ponds be Designed for Perfect-Mixing or Plug-Flow?" Water Science and Technology 23, no. 7-9 (April 1, 1991): 1495–502. http://dx.doi.org/10.2166/wst.1991.0602.

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The effect of the hydraulic flow pattern on the performance of Waste Stabilization Ponds is analyzed by modelling. The analysis is made on two parameters with different removal constants (Bacteria and BOD) and for the cases of steady hydraulic loading and when hydraulic loading changes on weekends. Plug-flow ponds perform much better than perfect mixed ones for removal of parameters with high removal constants such as bacteria. Plug-flow and perfect mixed ponds perform very similarly when the removal constant is low as for BOD. Changes in the hydraulic loading regime due to weekend effect do not modify the variability of outflow quality from plug-flow ponds. These changes do affect the variability of outflow quality from perfect mixed ponds only in the case of parameters with high removal constants such as bacteria. Polishing ponds Intended for bacterial removal should be designed for plug-flow. Facultative ponds intended for BOD removal may be designed for perfect mixed, partial mixed or plug-flow. Several small ponds with short residence time located In series, or the parcellation of a single big pond with widely spaced baffles, would avoid short circuiting of effluents between inlet and outlet. However, this design does not assure a plug-flow pattern, and it may lead to the formation of dead areas and the reduction of the actual residence time of effluents within the system.

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7

Johannsen, Ib, Björn Kilsgaard, Viktor Milkevych, and Dale Moore. "Design, Modelling, and Experimental Validation of a Scalable Continuous-Flow Hydrothermal Liquefaction Pilot Plant." Processes 9, no. 2 (January 27, 2021): 234. http://dx.doi.org/10.3390/pr9020234.

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In this study, the design and practical implementation of a novel, scalable plug-flow pilot plant for hydrothermal liquefaction of organic feedstock is presented. The overall discussion comprises the system’s design, process modelling, and simulation, as well as results for an experimental validation of the proposed design with a focus on fluid dynamics and heat transfer. The design criteria take into account the scalability of the plug-flow processing system, optimized non-isothermal flow conditions of highly viscous liquids in a tubular system at harsh process conditions, specifically high pressure and medium temperatures, and overall maintenance suitability. A novel forced flow oscillation system as well as unique heat exchange design to reduce the energy consumption during system operation, maximize local flow mixing, and minimize plugging are proposed and experimentally tested. To achieve a better understanding and optimization of Hydrothermal Liquefaction (HTL) (and other) processing systems, a mathematical model of heat transfer coupled with non-isothermal fluid flow was also developed and implemented.

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8

BULLOUGH, W. A., J. R. KINSELLA, D. J. PEEL, and U. S. URANG. "COMPUTATIONAL FLUID DYNAMICS MODELLING OF ELECTRO-STRUCTURED FLOWS." International Journal of Modern Physics B 15, no. 06n07 (March 20, 2001): 731–44. http://dx.doi.org/10.1142/s0217979201005210.

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The use of computational fluid dynamics (CFD) software for modelling the flow of electro-structured fluids is introduced. A non-Newtonian fluids package written specifically to model Bingham plastics is validated for several flow rates between stationary parallel plates for varying yield stresses, plate separations and lengths. The computing procedure is rationalised in terms of grid fitting of the 'plug' edge. The programme is modified to include an analytical expression which relates delectro-rheological fluid parameters. This approach is then used to predict valve flow rates from small sample, Couette viscometer produced data: its output compares with experimental results.

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9

Liotta, Flavia, Patrice Chatellier, Giovanni Esposito, Massimiliano Fabbricino, Eric D. Van Hullebusch, and Piet N. L. Lens. "Hydrodynamic Mathematical Modelling of Aerobic Plug Flow and Nonideal Flow Reactors: A Critical and Historical Review." Critical Reviews in Environmental Science and Technology 44, no. 23 (September 2, 2014): 2642–73. http://dx.doi.org/10.1080/10643389.2013.829768.

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10

Lapicque, F., and A. Storck. "Modelling of a continuous parallel plate plug flow electrochemical reactor: electrowinning of copper." Journal of Applied Electrochemistry 15, no. 6 (November 1985): 925–35. http://dx.doi.org/10.1007/bf00614369.

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11

Michelangelli, O. P., M. Yamanoi, A. Gaspar-Cunha, and J. A. Covas. "Modelling pellet flow in single extrusion with DEM." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 225, no. 4 (October 5, 2011): 255–68. http://dx.doi.org/10.1177/0954408911418159.

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Plasticating single-screw extrusion involves the continuous conversion of loose solid pellets into a pressurized homogeneous melt that is pumped through a shaping tool. Traditional analyses of the solids conveying stage assume the movement of an elastic solid plug at a fixed speed. However, not only the corresponding predictions fail considerably, but it is also well known that, at least in the initial screw turns, the flow of loose individual pellets takes place. This study follows previous efforts to predict the characteristics of such a flow using the discrete element method. The model considers the development of normal and tangential forces resulting from the inelastic collisions between the pellets and between them and the neighbouring metallic surfaces. The algorithm proposed here is shown to be capable of capturing detailed features of the granular flow. The predictions of velocities in the cross- and down-channel directions and of the coordination number are in good agreement with equivalent reported results. The effect of pellet size on the flow features is also discussed.

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12

Ramandi, Hamed Lamei, Peyman Mostaghimi, Ryan T. Armstrong, Christoph H. Arns, Mohammad Saadatfar, Rob M. Sok, Val Pinczewski, and Mark A. Knackstedt. "Pore scale imaging and modelling of coal properties." APPEA Journal 55, no. 2 (2015): 468. http://dx.doi.org/10.1071/aj14103.

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A key parameter in determining the productivity and commercial success of coal seam gas wells is the permeability of individual seams. Laboratory testing of core plugs is commonly used as an indicator of potential seam permeability. The highly heterogeneous and stress-dependent nature of coal makes laboratory measurements difficult to perform and the results difficult to interpret. Consequently, permeability in coal is poorly understood. The permeability of coal at the core scale depends on the geometry, topology, connectivity, mineralisation and spatial distribution of the cleat system, and a better understanding of coal permeability, that and the factors that control this depends on having a better understanding and detailed characterisation of the system. The authors used high resolution micro-focus X-ray computed tomography and 2D-3D image registration techniques to overlay tomograms of the same core plug, with and without X-ray attenuating fluids present in the pore space, with 2D scanning electron microscope images to produce detailed 3D visualisations of the geometry and topology of the cleat systems in the coal plugs. Novel filtering algorithms were used to produce segmentations that preserve cleat aperture dimensions and together with large-scale fluid flow simulations, they performed directly on the images and were used to compute porosities and permeabilities. Image resolution and segmentation sensitivity studies are also described, which show that the core scale permeability is controlled by a small number of well-connected percolating cleats. The results of this study demonstrate the potential of simple image-based analysis techniques to provide rapid estimates of core plug permeabilities.

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13

Vanrolleghem, P., and F. Coen. "Optimal design of in-sensor-experiments for on-line modelling of nitrogen removal processes." Water Science and Technology 31, no. 2 (January 1, 1995): 149–60. http://dx.doi.org/10.2166/wst.1995.0091.

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In-Sensor-Experiments are proposed as a means of providing highly informative data concerning the bioprocesses occurring in N-removal systems. It is highlighted that the changing nature of both wastewater and activated sludge enforces the continuous adjustment of the proposed In-Sensor-Experiments to maintain the quality of the sensor's outputs. Central to the automated design of the experiments performed in these adaptive sensors is a mathematical representation of the processes occurring in the device. This model is continuously updated on the basis of previously acquired data. It is illustrated how different design criteria (objective functions), such as most reliable model selection capability or minimal parameter variance, influence the experimental designs. The concepts are illustrated with real-life data from two types of In-Sensor-Experiments. First, short-term (fed-)batch respirometric experiments are used to estimate the biokinetics of the nitrifying population. Second, a new device is presented in which a sensing element is placed at the end of a plug-flow reactor, hence the term “Plug-Flow-Sensor”. The optimally designed and continuously updated variation of the flow rate through the plug flow reactor results in a retention time distribution. This allows us to monitor a variable as function of the reaction time and this within a narrow (user-specified) window of reaction times, increasing the measuring frequency and accuracy compared to equivalent batch experiments. As a first example, ORP is applied as measured variable. By using ORP “nitrate knees” can be detected after a certain reaction time. This information is an indicator of the denitrifying capacity of the sludge.

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14

Hasan Ali San. "A kinetic model for ideal plug-flow reactors." Water Research 23, no. 5 (May 1989): 647–54. http://dx.doi.org/10.1016/0043-1354(89)90031-6.

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15

Khalil, Charbel Abou, Mohamed T. Eraky, and Sophia Ghanimeh. "Localized mixing of anaerobic plug flow reactors." Water Research 204 (October 2021): 117588. http://dx.doi.org/10.1016/j.watres.2021.117588.

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16

Tunçsiper, B., S. Ç. Ayaz, and L. Akça. "Modelling and evaluation of nitrogen removal performance in subsurface flow and free water surface constructed wetlands." Water Science and Technology 53, no. 12 (June 1, 2006): 111–20. http://dx.doi.org/10.2166/wst.2006.412.

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With the aim of protecting drinking water sources in rural regions, pilot-scale subsurface water flow (SSF) and free water surface flow (FWS) constructed wetland systems were evaluated for removal efficiencies of nitrogenous pollutants in tertiary stage treated wastewaters (effluent from the Paşaköy biological nutrient removal plant). Five different hydraulic application rates and emergent (Canna, Cyperus, Typhia sp., Phragmites sp., Juncus, Poaceae, Paspalum and Iris) and floating (Pistia, Salvina and Lemna) plant species were assayed. The average annual NH4-N, NO3-N and organic-N treatment efficiencies were 81, 40 and 74% in SSFs and 76, 59 and 75% in FWSs, respectively. Two types of the models (first-order plug flow and multiple regression) were tried to estimate the system performances. Nitrification, denitrification and ammonification rate constants (k20) values in SSF and FWS systems were 0.898 d−1 and 0.541 d−1, 0.486 d−1 and 0.502 d−1, 0.986 d−1 and 0.908, respectively. Results show that the first-order plug flow model clearly estimates slightly higher or lower values than observed when compared with the other model.

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17

Watson, Bruce, Mark Rupke, Imre Takács, and Gilles Patry. "MODELLING OF FULL-SCALE WASTEWATER TREATMENT PLANTS: HOW DETAILED SHOULD IT BE?" Water Science and Technology 30, no. 2 (July 1, 1994): 141–47. http://dx.doi.org/10.2166/wst.1994.0037.

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Dynamic mathematical modelling of full-scale wastewater treatment plants requires an optimal level of detail to be accurate, effective, but still manageable. Single process models tend to oversimplify the complexities of a large-scale plant and result in erroneous calibrated parameter values or limited predictive power for the model – on the other hand, modelling of every process and process unit is usually impractical, since it cannot be supported by reliable plant data, and requires prohibitive sampling costs and effort. Level of aggregation, settler dimensionality and reactivity, and plug-flow hydraulics were investigated with the help of a sophisticated dynamic modelling package. The results show that there is no general rule or global ‘optimal level’ of modelling – the required modelling detail is a function of influent flow and loading levels, and processes to be simulated (BOD removal, nitrification-denitrification, biological phosphorus removal, settling). In the case of real-life plants, supportable modelling level is often constrained by data availability and reliability.

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18

CHIAO, LEROY, and ROBERT G. RINKER. "ON THE USE OF APPROXIMATIONS IN THE MODELLING OF PLUG-FLOW REACTORS UNDER PERIODIC OPERATION." Chemical Engineering Communications 57, no. 1-6 (July 1987): 153–65. http://dx.doi.org/10.1080/00986448708960482.

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19

Ellam, D. J., W. A. Bullough, and R. J. Atkin. "Modelling the flow of an electrostructured fluid in transient operation." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 219, no. 1 (February 1, 2005): 61–75. http://dx.doi.org/10.1243/095765005x6890.

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This paper is primarily concerned with the feasibility of modelling the flow of electro-structured fluids (ESFs) by the use of computational fluid dynamics (CFD). The non-steady performance of specimen devices in which power, force, or torque is transmitted via an ESF is predicted. This is achieved by incorporating a Bingham plastic type model into a commercial CFD package. Adequately describing the rheology of these fluids requires the use of several parameters. The presence of plug flow and unsteady terms in the equations of motion adds a certain complexity, and a future view of including heat transfer, field distributions, and electrical conductance adds even more difficulty. For enabling practical device development/ optimization studies that incorporate these features, an approach utilizing a well-endowed CFD package for this purpose is near essential. The results are verified by experiments that represent a wide range of flow situations. For experimentation, an electrorheological (ER) fluid is used as the test medium on the grounds of convenience owing to the current availability of a reliable fluid with some characterization. However, the CFD procedures apply both to ER and to magnetorheological (MR) fluids.

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20

King, Andrew C., Cynthia A. Mitchell, and Tony Howes. "Hydraulic tracer studies in a pilot scale subsurface flow constructed wetland." Water Science and Technology 35, no. 5 (March 1, 1997): 189–96. http://dx.doi.org/10.2166/wst.1997.0195.

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Current design procedures for Subsurface Flow (SSF) Wetlands are based on the simplifying assumptions of plug flow and first order decay of pollutants. These design procedures do yield functional wetlands but result in over-design and inadequate descriptions of the pollutant removal mechanisms which occur within them. Even though these deficiencies are often noted, few authors have attempted to improve modelling of either flow or pollutant removal in such systems. Consequently the Oxley Creek Wetland, a pilot scale SSF wetland designed to enable rigorous monitoring, has recently been constructed in Brisbane, Australia. Tracer studies have been carried out in order to determine the hydraulics of this wetland prior to commissioning it with settled sewage. The tracer studies will continue during the wetland's commissioning and operational phases. These studies will improve our understanding of the hydraulics of newly built SSF wetlands and the changes brought on by operational factors such as biological films and wetland plant root structures. Results to date indicate that the flow through the gravel beds is not uniform and cannot be adequately modelled by a single parameter, plug flow with dispersion, model. We have developed a multiparameter model, incorporating four plug flow reactors, which provides a better approximation of our experimental data. With further development this model will allow improvements to current SSF wetland design procedures and operational strategies, and will underpin investigations into the pollutant removal mechanisms at the Oxley Creek Wetland.

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21

Chen, Chao, Guo Guang Cheng, Hai Bo Sun, Xin Chao Wang, and Jia Quan Zhang. "Optimization of Flow Control Devices in a Stainless Steel Tundish." Advanced Materials Research 476-478 (February 2012): 156–63. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.156.

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Optimization of FCD design in a single strand slab tundish producing stainless steel is carried out by physical modelling using a 0.4 scale water model and mathematical modelling study. Reducing the residual metal volume at the end of casting, promoting the near-surface plug flow for inclusions removal and improving the transient slab quality are concerned, the optimized FCD is two dams and an impact pad, among them the dam1 (close to ladle shroud) with two 30 degrees upward inclined drain holes, another dam2 (close to tundish exit) is bottom rectangular-grooved which is beneficial for reducing the residual metal volume. Besides, the height of impact pad and drain holes must be concerned simultaneously, in the present study the height is 20mm and 60mm, respectively. Compared with turbulence inhibitors, impact pad will decrease the melt exposed to air at the steady state of casting. The holes at the higher level of dam may cause slag entrapment during the refilling process of ladle change operation.

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22

Van Gauwbergen, D., and J. Baeyens. "Macroscopic fluid flow conditions in spiral wound membrane elements: packed bed approach." Water Science and Technology 41, no. 10-11 (May 1, 2000): 85–91. http://dx.doi.org/10.2166/wst.2000.0615.

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The modelling of the reverse osmosis process is needed to fully evaluate its potential and facilitate scale up. The definition of the flow regime in the concentrate channel is of paramount importance. The present paper describes our experimental investigations on RTD and relates the RTD response curves to the regime of flow in the concentrate channel. Results demonstrate (i) that dead zones are present; (ii) that both a Plug Flow with Dispersion (PFD) and Probabilistic Time Delay (PTD) model can be used to characterise the flow; and (iii) that PFD- and PTD-model parameters assume nearly constant values for a given geometry which simplifies the prediction of the RTD for any desired flow rate.

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23

Sans, C., J. Mata-Alvarez, F. Cecchi, and P. Pavan. "Modelling of a plug-flow pilot reactor producing VFA by anaerobic fermentation of municipal solid wastes." Water Science and Technology 30, no. 12 (December 1, 1994): 125–32. http://dx.doi.org/10.2166/wst.1994.0595.

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The production of volatile fatty acids (VFA) by anaerobic fermentation of municipal solid wastes was studied at pilot-plant level. A plug-flow reactor (80 1 total volume) without solid or liquid recirculation was employed to digest a mixture of two types of organic fraction of the municipal solid waste (OFMSW): OFMSW mechanically selected and OFMSW coming from a market of fruit and vegetables. The acidogenic process was studied at different retention times (between 2 and 6 days) in the mesophilic (37° ± 2°C) range of temperature. The VFA concentration obtained in the first valve of the tubular reactor ranged from 9.1 to 13.4 g 1−1 and in the outlet sludge oscillated between 11.8 and 23.1 g 1−1, increasing when increasing retention time from 2 to 6 days. A mathematical model of a continuous steady state plug-flow reactor proposed in a previous paper was used to represent the VFA production obtained experimentally. The results obtained when fitting the mathematical model with the experimental results were not sufficiently good. Some modifications of the initial model were considered. The best fitting of the results was obtained when the inhibition effect of the fermentation product on microorganisms growth was taken into account. The errors of this fitting, calculated by least squares, can be considered optimal for retention times between 4 and 6 days, while at shorter retention times the inhibition effect of pH and product makes the volatile acid production lower than the values obtained experimentally.

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24

Ebuehi, Osaretin N. I., Kingsley Abhulimen, and Daniel O. Adebesin. "Modelling Production of Renewable Energy from Water Splitting High Thermal Electrolysis Processes." European Journal of Engineering and Technology Research 6, no. 3 (April 12, 2021): 14–21. http://dx.doi.org/10.24018/ejers.2021.6.3.2391.

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Recently, fuel gas from water has become the center of attention because it is a renewable source of energy and eco-friendly. In this study, the hydrogen gas simulated was obtained from the high-temperature water splitting electrolysis model, because it is more efficient than the low-temperature water splitting electrolysis process. It also releases oxygen as a byproduct. The high-temperature electrolysis model is made up of three loops: primary high-temperature helium loop, secondary helium loop, and high-temperature electrolysis loop. Hydrogen gave a temperature of 27.20C, a pressure of 49.5 bars, and a molar flow of 84.02MMSCFD. The hydrogen gas from a high-temperature electrolysis model is simulated with a CO2 gas stream to produce methane and water, also releasing unreacted carbon dioxide and hydrogen. Key parameters such as molar entropy, molar enthalpy, heat flow, and cost flow were evaluated by Aspen HYSYS V8.8. The simulation model used for this work is the Sabatier Process Model. In this model, Continuous stirred tank, Converter, Equilibrium, Gibbs, Plug flow reactors were used to generate methane. The Converter reactor gave the highest yield of methane gas with a mole fraction of 0.2390. Key benchmarks, including temperature, heat flow, cost flow, cost factor were varied to see how they can affect methane gas and other products.

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25

Ebuehi, Osaretin N. I., Kingsley Abhulimen, and Daniel O. Adebesin. "Modelling Production of Renewable Energy from Water Splitting High Thermal Electrolysis Processes." European Journal of Engineering and Technology Research 6, no. 3 (April 12, 2021): 79–86. http://dx.doi.org/10.24018/ejeng.2021.6.3.2391.

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Recently, fuel gas from water has become the center of attention because it is a renewable source of energy and eco-friendly. In this study, the hydrogen gas simulated was obtained from the high-temperature water splitting electrolysis model, because it is more efficient than the low-temperature water splitting electrolysis process. It also releases oxygen as a byproduct. The high-temperature electrolysis model is made up of three loops: primary high-temperature helium loop, secondary helium loop, and high-temperature electrolysis loop. Hydrogen gave a temperature of 27.20C, a pressure of 49.5 bars, and a molar flow of 84.02MMSCFD. The hydrogen gas from a high-temperature electrolysis model is simulated with a CO2 gas stream to produce methane and water, also releasing unreacted carbon dioxide and hydrogen. Key parameters such as molar entropy, molar enthalpy, heat flow, and cost flow were evaluated by Aspen HYSYS V8.8. The simulation model used for this work is the Sabatier Process Model. In this model, Continuous stirred tank, Converter, Equilibrium, Gibbs, Plug flow reactors were used to generate methane. The Converter reactor gave the highest yield of methane gas with a mole fraction of 0.2390. Key benchmarks, including temperature, heat flow, cost flow, cost factor were varied to see how they can affect methane gas and other products.

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26

Lazar, Liliana, Heinz Koeser, Ioana Fechete, and Ion Balasanian. "A Modelling Approach of the Catalytic Oxidation of Volatile Organic Compounds in the SCR-DeNOx Monolithic Reactor." Revista de Chimie 71, no. 7 (August 4, 2020): 79–87. http://dx.doi.org/10.37358/rc.20.7.8227.

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Monolithic reactors play an important role in the integrated approach to environmental protection, especially in air pollution abatement. Mathematical modelling of catalytic reactors has become a key procedure in the design, development and optimisation of many industrial processes. The objective of this study was the modelling and simulation of the catalytic oxidation of volatile organic compounds by a commercial V2O5-WO3/TiO2 honeycomb catalyst, specific for the SCR-DeNOx process in high-dust flue gases from stationary incineration. The mathematical model is developed for the numerical simulation of a tubular plug flow reactor, using mass balance equation to predict results for benzene conversion under isothermal conditions.

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27

Deygout, C., A. Lesne, F. Campillo, and A. Rapaport. "Homogenised model linking microscopic and macroscopic dynamics of a biofilm: Application to growth in a plug flow reactor." Ecological Modelling 250 (February 2013): 15–24. http://dx.doi.org/10.1016/j.ecolmodel.2012.10.020.

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28

Hayes, C. R., T. N. Croft, A. Campbell, I. P. Douglas, P. Gadoury, and M. R. Schock. "Computational modelling techniques in the optimization of corrosion control for reducing lead in Canadian drinking water." Water Quality Research Journal 49, no. 1 (October 15, 2013): 82–93. http://dx.doi.org/10.2166/wqrjc.2013.009.

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Compliance modelling has been used to good effect in the optimization of plumbosolvency control in the UK and was evaluated in the Canadian and US contexts via three case studies. In relation to regulatory compliance, supplementary orthophosphate dosing could be justified in one water supply system but not in one other. Compliance modelling indicated that Health Canada's Tier 1 protocol is much less stringent than its Tier 2 protocol and that optimization based on 6+ hour stagnation samples vs 15 μg/l is likely to be more stringent than that based on 30 min stagnation samples vs 10 μg/l. The modelling of sequential sampling for an individual home indicated that sample results could be markedly affected by the length of the lead service line, by the length of the copper premise pipe and by pipe diameters. The results for sequential sampling were also dependent on flow characteristics (plug vs laminar). For either regulatory compliance assessment or for the optimization of plumbosolvency control measures, routine sequential sampling from the same houses at a normalized flow will minimize these variable effects.

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29

Markoš, Jozef, and Alena Brunovská. "Modelling of fixed bed catalytic reactors with catalyst deactivation under constant-pattern travelling wave assumption." Collection of Czechoslovak Chemical Communications 53, no. 1 (1988): 45–55. http://dx.doi.org/10.1135/cccc19880045.

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The models of fixed bed catalytic reactors in which catalyst deactivation takes place can be significantly simplified by introducing quasi-steady state and constant-pattern travelling wave assumption. This results in faster algorithms. In the present paper the plug-flow, radial dispersion, and well-mixed regions in the series pseudohomogenous models under the above assumptions are discussed. The obtained results are compared with experimental ones in the case of hydrogenation of benzene on a nickel catalyst with thiophene as a poison (irreversible deactivation).

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30

Salter, H. E., C. T. Ta, S. K. Ouki, and S. C. Williams. "Three-dimensional computational fluid dynamic modelling of a facultative lagoon." Water Science and Technology 42, no. 10-11 (November 1, 2000): 335–42. http://dx.doi.org/10.2166/wst.2000.0674.

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A series of facultative lagoons operated by Thames Water treating industrial wastewater in Thailand were found to be performing poorly, particularly with respect to the removal of biological oxygen demand (BOD). A review of the design parameters for the site found that all the lagoons are of a sufficient area for the flow and BOD load. However, observations of the lagoons suggested that there may be significant hydraulic short-circuiting. Computational fluid dynamics (CFD) modelling was therefore carried out on one of the lagoons to establish the hydraulic regime. Two consecutive simulations were carried out, both with and without baffles; the first to establish steady flow conditions, and the second using a chemical species transport model to obtain the residence time distribution (RTD). The results of the modelling indicate that the lagoons do currently suffer from significant short-circuiting, and large dead-zones are present. The installation of baffles in the CFD model improved the plug-flow characteristics of the lagoons, substantially reducing the short-circuiting and the size of the dead-zones. It has therefore been concluded that the installation of baffles in the lagoons will lead to an improvement in their performance, by increasing the retention time of the system.

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31

Olsvik, O., and F. Billaud. "Modelling of the decomposition of methane at 1273 K in a plug flow reactor at low conversion." Journal of Analytical and Applied Pyrolysis 25 (June 1993): 395–405. http://dx.doi.org/10.1016/0165-2370(93)80058-8.

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32

Donoso-Bravo, Andrés, Constanza Sadino-Riquelme, Daniel Gómez, Camilo Segura, Emky Valdebenito, and Felipe Hansen. "Modelling of an anaerobic plug-flow reactor. Process analysis and evaluation approaches with non-ideal mixing considerations." Bioresource Technology 260 (July 2018): 95–104. http://dx.doi.org/10.1016/j.biortech.2018.03.082.

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33

Kuljanin, Aleksandra, and Natasa Gros. "LabVIEW virtual instrument for zone penetration studies in flow-based analytical systems." Journal of the Serbian Chemical Society, no. 00 (2021): 58. http://dx.doi.org/10.2298/jsc210709058k.

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In the flow method development, zone penetration studies are usually conducted as a part of the initial screening phase. A lack of an appropriate tool can keep these studies on the level of rough estimations. The developed LabVIEW virtual instrument (VI) which processes peak signals and calculates the overlapping area and fundamental peak-related parameters was used for the calculations in experiments that are modelling sample and reagent plug inter-action within liquid conduits. The reliability of the predictions was initially confirmed on the artificial data set based on thirty-six files covering all the different types of cases that can be foreseen. To continue, the volumes of model solutions, propelling flow rate, and the coil length in the sequential injection analysis system, were varied by following the Box?Behnken response surface design. In three examples, it is demonstrated how the VI can help the planning of further experiments in the range which ensures the efficient zone overlap-ping, the economic exploitation of reagent plug and the adequate dispersion. The application of the VI is not limited just to the flow-based chemistry, it can also be used in spectroscopy and chromatography. In order to use the graphical user interface, it is not necessary to have the LabVIEW program installed.

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34

Kaplan, Louis A., and J. Denis Newbold. "Measurement of streamwater biodegradable dissolved organic carbon with a plug-flow bioreactor." Water Research 29, no. 12 (December 1995): 2696–706. http://dx.doi.org/10.1016/0043-1354(95)00135-8.

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35

Zhang, Jiangshan, Shufeng Yang, Jingshe Li, Haiyan Tang, and Zhengyi Jiang. "The Effect of a Dissipative Ladle Shroud on Mixing in Tundish: Mathematical and Experimental Modelling." High Temperature Materials and Processes 37, no. 1 (January 26, 2018): 25–32. http://dx.doi.org/10.1515/htmp-2016-0093.

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AbstractThe effect of a dissipative ladle shroud (DLS) on mixing in tundish was investigated, compared with that of a conventional ladle shroud (CLS) using mathematical and physical modelling. The tracer profiles of mathematical results, achieved using large eddy simulation, were validated by physical observations employing high-speed cinephotography. The design of a DLS dramatically changed the flow patterns and contributed the intermixing of fluid elements inside the ladle shroud. The vortex flow encouraged the turbulent mixing and was verified by tracking of physical tracer dispersion inside the DLS. Residence Time Distribution (RTD) curves were obtained in two different sized tundishes to examine the mixing behaviours. The findings indicated that the DLS benefited the tundish mixing in terms of increasing active volume. The effect seemed to be more remarkable in the smaller tundish. The DLS gave rise to a more plug-like flow pattern inside the tundish, showing potential to shorten the transition length during grade change.

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36

Grzywacz, Robert. "Continuous mathematical models of airlift bioreactors: Families, affinity, diversity and modelling for single-substrate kinetics." Chemical and Process Engineering 33, no. 2 (June 1, 2012): 291–309. http://dx.doi.org/10.2478/v10176-012-0027-9.

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Continuous mathematical models of airlift bioreactors: Families, affinity, diversity and modelling for single-substrate kinetics This paper presents a method of describing an airlift bioreactor, in which biodegradation of a carbonaceous substrate described by single-substrate kinetics takes place. Eight mathematical models based on the assumption of liquid plug flow and axial dispersion flow through the riser and the downcomer in the reactor were proposed. Additionally, the impact of degassing zone with assumed complete mixing on the obtained results was analyzed. Calculations were performed for two representative hydrodynamic regimes of reactor operation, i.e. with the presence of gas bubbles only within the riser and for complete gas circulation. The conclusions related to the apparatus design and process performance under sufficient aeration of the reaction mixture were drawn on the basis of the obtained results.

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37

Alexiadis, Alessio. "Bubble dispersion patterns in bubbly-flow released from a porous plug into a gas-stirred ladle." Applied Mathematical Modelling 31, no. 8 (August 2007): 1534–47. http://dx.doi.org/10.1016/j.apm.2006.05.005.

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38

Roy, Caroline S., Guylaine Talbot, Edward Topp, Carole Beaulieu, Marie-France Palin, and Daniel I. Massé. "Bacterial community dynamics in an anaerobic plug-flow type bioreactor treating swine manure." Water Research 43, no. 1 (January 2009): 21–32. http://dx.doi.org/10.1016/j.watres.2008.09.034.

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39

Piazza, Stefania, Mariacrocetta Sambito, and Gabriele Freni. "A Novel EPANET Integration for the Diffusive–Dispersive Transport of Contaminants." Water 14, no. 17 (August 31, 2022): 2707. http://dx.doi.org/10.3390/w14172707.

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The EPANET model is commonly used to model hydraulic behaviour and water quality within water distribution networks. The standard version of the model solves the advective transport equation by solving a mass balance of the fundamental plug flow substance that considers the advective transport and kinetic reaction processes. Over the years, several versions of the model have been developed, which have made it possible to improve the modelling of water quality through the introduction of additional terms within the transport equation to solve the problem of dispersive transport (EPANET-AZRED) and to consider multiple interacting species in the mass flow and on the pipe walls (EPANET multi-species extension). The present study proposes a novel integration of the EPANET-DD (dynamic-dispersion) model, which enables the advective–diffusive–dispersive transport equation in dynamic flow conditions to be solved in the two-dimensional case, through the classical random walk method, implementing the diffusion and dispersion equations proposed by Romero-Gomez and Choi (2011). The model was applied to the University of Enna “KORE” laboratory network to verify its effectiveness in modelling diffusive–dispersive transport mechanisms in the presence of variable flow regimes. The results showed that the EPANET-DD model could better represent the actual data than previously developed versions of the EPANET model.

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40

Scott, Lewis, Antonia Borissova, Alan Burns, and Mojtaba Ghadiri. "Analysis of hold-up and grinding pressure in a spiral jet mill using CFD-DEM." EPJ Web of Conferences 249 (2021): 12004. http://dx.doi.org/10.1051/epjconf/202124912004.

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A spiral jet mill was simulated using Discrete Element Method modelling and Computational Fluid Dynamics. The particle behaviour and fluid motion were analysed as a function of hold-up and grinding pressure. Particle collision energy was predicted to be prevalent along the bed surface and in front of the grinding jets, as shown through the collision data recorded. The bed itself affects the fluid flow field, as momentum is transferred to the particles. Increasing the grinding pressure does not result in a proportional increase in the kinetic energy of the particle system, as the high pressure jets begin to penetrate the bed with greater ease. The particle bed moves as ‘plug-flow’, with the layers of the bed closest to chamber wall.

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41

Sousa, José M., та Adélio Mendes. "Modelling a catalytic membrane reactor with plug flow pattern and a hypothetical equilibrium gas-phase reaction with Δn≠0". Catalysis Today 104, № 2-4 (червень 2005): 336–43. http://dx.doi.org/10.1016/j.cattod.2005.03.058.

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42

Bartenbach, B., C. Hirsch, M. Huth, and W. Leuckel. "Modelling and validation of soot concentration patterns of turbulent diffusion flames based on data from plug flow reactor experiments." Chemical Engineering and Processing: Process Intensification 33, no. 5 (November 1994): 401–8. http://dx.doi.org/10.1016/0255-2701(94)02012-4.

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43

Saunders, D. Curtis, and Jeffrey S. Marshall. "Transient lift force on a blade during cutting of a vortex with non-zero axial flow." Journal of Fluid Mechanics 819 (April 18, 2017): 258–84. http://dx.doi.org/10.1017/jfm.2017.188.

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The problem of orthogonal penetration of a blade into the core of a vortex with non-zero axial flow was studied using a combination of scaling theory, a heuristic plug-flow model and full Navier–Stokes simulations. The particular focus of this paper was to understand the mechanics of the transient lift force that occurs during the initial penetration of the blade leading edge into the vortex core, and the relationship of this transient force to the steady-state lift force that develops due to the difference in vortex core radius over the blade surface. The three modelling approaches all lead to the conclusion that the maximum value of the lift coefficient for the transient blade penetration force is proportional to the impact parameter and inversely proportional to the axial flow parameter. This observation is used to develop a simple expression that collapses the predictions of the full Navier–Stokes simulations for lift coefficient over a wide range of parameter values.

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44

Stamou, Anastasios I. "Modelling of oxidation ditches using an open channel flow 1-D advection-dispersion equation and ASM1 process description." Water Science and Technology 36, no. 5 (September 1, 1997): 269–76. http://dx.doi.org/10.2166/wst.1997.0214.

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A river water quality model is presented for the prediction of the concentration fields of the water quality variables in an oxidation ditch performing carbon oxidation, nitrification and denitrification. The model involves the one-dimensional convection-dispersion equations for all the variables, which are described in the IAWPRC Activated Sludge Model No 1. The model is applied to a typical oxidation ditch to show that all variables, with the exception of DO, are uniformly distributed in the ditch; thus permitting the characterisation of the oxidation ditch as a completely mixed reactor. The DO concentration, which controls the reaction rates of almost all the processes, shows a plug flow behaviour. The potential of the present model to be used to improve the DO control system of the ditch and to perform real time predictions is also demonstrated. All calculations have been performed with a PC.

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45

Amaral, Andreia, Oliver Schraa, Leiv Rieger, Sylvie Gillot, Yannick Fayolle, Giacomo Bellandi, Youri Amerlinck, et al. "Towards advanced aeration modelling: from blower to bubbles to bulk." Water Science and Technology 75, no. 3 (September 29, 2016): 507–17. http://dx.doi.org/10.2166/wst.2016.365.

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Aeration is an essential component of aerobic biological wastewater treatment and is the largest energy consumer at most water resource recovery facilities. Most modelling studies neglect the inherent complexity of the aeration systems used. Typically, the blowers, air piping, and diffusers are not modelled in detail, completely mixed reactors in a series are used to represent plug-flow reactors, and empirical correlations are used to describe the impact of operating conditions on bubble formation and transport, and oxygen transfer from the bubbles to the bulk liquid. However, the mechanisms involved are very complex in nature and require significant research efforts. This contribution highlights why and where there is a need for more detail in the different aspects of the aeration system and compiles recent efforts to develop physical models of the entire aeration system (blower, valves, air piping and diffusers), as well as adding rigour to the oxygen transfer efficiency modelling (impact of viscosity, bubble size distribution, shear and hydrodynamics). As a result of these model extensions, more realistic predictions of dissolved oxygen profiles and energy consumption have been achieved. Finally, the current needs for further model development are highlighted.

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46

Smeets, P. W. M. H., A. W. C. van der Helm, Y. J. Dullemont, L. C. Rietveld, J. C. van Dijk, and G. J. Medema. "Inactivation of Escherichia coli by ozone under bench-scale plug flow and full-scale hydraulic conditions." Water Research 40, no. 17 (October 2006): 3239–48. http://dx.doi.org/10.1016/j.watres.2006.06.025.

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47

Jacobsen, J. L., H. Madsen, and P. Harremoès. "A stochastic model for two-station hydraulics exhibiting transient impact." Water Science and Technology 36, no. 5 (September 1, 1997): 19–26. http://dx.doi.org/10.2166/wst.1997.0156.

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The objective of the paper is to interpret data on water level variation in a river affected by overflow from a sewer system during rain. The simplest possible, hydraulic description is combined with stochastic methods for data analysis and model parameter estimation. This combination of deterministic and stochastic interpretation is called grey box modelling. As a deterministic description the linear reservoir approximation is used. A series of linear reservoirs in sufficient number will approximate a plug flow reactor. The choice of number is an empirical expression of the longitudinal dispersion in the river. This approximation is expected to be a sufficiently good approximation as a tool for the ultimate aim: the description of pollutant transport in the river. The grey box modelling involves a statistical tool for estimation of the parameters in the deterministic model. The advantage is that the parameters have physical meaning, as opposed to many other statistically estimated, empirical parameters. The identifiability of each parameter, the uncertainty of the parameter estimation and the overall uncertainty of the simulation are determined.

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48

Ballyk, Mary, and Hal Smith. "A model of microbial growth in a plug flow reactor with wall attachment." Mathematical Biosciences 158, no. 2 (May 1999): 95–126. http://dx.doi.org/10.1016/s0025-5564(99)00006-1.

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49

Alam, Md Saiful, Agung Tri Wijayanta, Koichi Nakaso, Jun Fukai, Koyo Norinaga, and Jun-ichiro Hayashi. "A reduced mechanism for primary reactions of coal volatiles in a plug flow reactor." Combustion Theory and Modelling 14, no. 6 (October 2010): 841–53. http://dx.doi.org/10.1080/13647830.2010.517273.

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50

Ramasetti, Visuri, Sulasalmi, Fabritius, Savolainen, and Li. "Numerical Modelling of the Influence of Argon Flow Rate and Slag Layer Height on Open-Eye Formation in a 150 Ton Steelmaking Ladle." Metals 9, no. 10 (September 26, 2019): 1048. http://dx.doi.org/10.3390/met9101048.

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A transient computational fluid dynamics (CFD) modelling approach was used to study the complex multi-phase flow in an argon-stirred industrial scale ladle with a nominal capacity of 150 tons. During the stirring process, when gas was injected through the porous plug from the bottom into the steel bath, it breaks up into bubbles and infringes the slag layer creating an open-eye. The volume of fluid model was used to investigate the open-eye formation process in the simulations. In the numerical simulations, the open-eye area changed from 0.7 to 2.24 m2 with the increment of argon flow rate from 200 to 500 NL/min for slag layer thickness of 40 cm. Furthermore, the influence of slag layer height on the open-eye area was investigated. An argon flow rate of 200 NL/min was able to break the slag layer for slag layer height of 40 cm, and the open-eye formation was not possible for the same flow rate when the slag layer height was elevated from 40 to 55 cm. The numerical simulation results were validated against industrial measurements carried out at Outokumpu Stainless located in Tornio, Finland. The numerical simulation results of dynamics and time-averages of the slag area showed a good agreement when compared to the industrial measurements. To conclude, it is necessary to define gas flow rate based on the slag layer height to have an open-eye suitable for alloying.

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