Records with Subject: Modelling and Simulations
Showing records 1 to 25 of 637. [First] Page: 1 2 3 4 5 Last
Influence of Surface Waviness of Journal and Bearing Bush on the Static Characteristics of Hydrodynamic Bearing
Minghui Yang, Hong Lu, Xinbao Zhang, Meng Duan, Liu Bao, Bowen Wang, Wan Wu
January 24, 2022 (v1)
Keywords: finite difference method, hydrodynamic journal bearing, static characteristics, surface waviness
An investigation on the surface waviness of both the journal and the bearing bush and their impact on the static characteristics of the hydrodynamic journal bearing is presented in this paper. The finite difference method is introduced to solve a Reynolds equation and obtain the unknown pressure field. The static characteristics, including the load carrying capacity, attitude angle, end leakage flow rate and frictional coefficient are studied under different waviness parameters. The numerically simulated results indicate that the waviness of the bearing bush may deteriorate or enhance the bearing system, depending on the phase angle. The waviness of the journal causes periodic changes in bearing behavior, owing to the alteration in the phase angle. The profile of the journal and bearing surfaces near the attitude angle determines the performance of the bearing system.
Investigation on the Performance Enhancement and Emission Reduction of a Biodiesel Fueled Diesel Engine Based on an Improved Entire Diesel Engine Simulation Model
Weigang Yu, Zhiqing Zhang, Bo Liu
January 24, 2022 (v1)
Keywords: biodiesel fuel, comprehensive performance, diesel engine, fuel injection rate, fuel injection system
In order to improve the efficiency of the diesel engine and reduce emissions, an improved heat transfer model was developed in an AVL-BOOST environment which is a powerful and user-friendly software for engine steady-state and transient performance analysis. The improved heat transfer model considers the advantages of the Woschni1978 heat transfer model and Honhenberg heat transfer model. In addition, a five-component biodiesel skeletal mechanism containing 475 reactions and 134 species was developed to simulate the fuel spray process and combustion process since it contained methyl linolenate, methyl linoleate, methyl oleate, methyl stearate, and methyl palmitate, which are a majority component in most biodiesel. Finally, the propulsion and load characteristics of a diesel engine fueled with biodiesel fuel were investigated by the improved heat transfer model in term of power, brake specific fuel consumption (BSFC), soot and NOx emissions. Similarly, the effects of the fuel injection... [more]
Learn Aspen Plus in 24 Hours 2nd Edition Solution Files
Thomas A. Adams II
January 6, 2022 (v1)
Keywords: Aspen Plus, Education, Learn Aspen Plus in 24 Hours, Simulation
These Aspen Plus v12 simulations are the solution or demonstration files for the book Learn Aspen Plus in 24 Hours, 2nd Edition, by Thomas A. Adams II. They are given as-is with no warranty or guarantee of accuracy or correctness. They are for educational purposes only.

The files list contains a large .zip of all files, or otherwise you can download them independently.

Files correspond to these tutorials:

Tutorial 2 Physical Property Modelling - Selecting physical properties. Understanding the database.
Tutorial 3 Problem Solving Tools - Design Specs and Sensitivity Analyses
Tutorial 4 Heat Exchangers - HEATER, HEATX
Tutorial 5 Equilibrium-based Distillation Models - RadFrac (in equilibrium mode)
Tutorial 6 Advanced Problem Solving Tools - Utilities, GHG Emissions, Optimization
Tutorial 7 Chemical Reactor Models - RSTOIC, REQUIL, RYIELD, RGIBBS, RCSTR, RPFR
Tutorial 8 Rate-based Distillation Models - RadFrac (in rate-based mode)
Tutorial 9 Custom Models and External Con... [more]
Supplemental Data for “Process Design and Techno-Economic Analysis of Biomass Pyrolysis By-Product Utilization in the Ontario and Aichi Steel Industries”
Jamie Rose, Thomas A. Adams II
November 5, 2021 (v1)
This is supplemental data for a paper submitted to the PSE 2021+ conference. It includes values used to calculate emissions reductions and financial value of biomass pyrolysis by-product utilization.
Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace
Bo Zhang, Sizhi Zeng, Fenghua Tang, Shujun Hu, Qiang Zhou, Yigang Jia
October 14, 2021 (v1)
Keywords: energy dissipation capacity, initial strain, loading rate, shape memory alloy (SMA), strain amplitude
As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate incre... [more]
Computational Fluid Dynamics Modeling of Rotating Annular VUV/UV Photoreactor for Water Treatment
Minghan Luo, Wenjie Xu, Xiaorong Kang, Keqiang Ding, Taeseop Jeong
October 14, 2021 (v1)
Keywords: Computational Fluid Dynamics, MB, photoreactor, VUV, water treatment
The ultraviolet photochemical degradation process is widely recognized as a low-cost, environmentally friendly, and sustainable technology for water treatment. This study integrated computational fluid dynamics (CFD) and a photoreactive kinetic model to investigate the effects of flow characteristics on the contaminant degradation performance of a rotating annular photoreactor with a vacuum-UV (VUV)/UV process performed in continuous flow mode. The results demonstrated that the introduced fluid remained in intensive rotational movement inside the reactor for a wide range of inflow rates, and the rotational movement was enhanced with increasing influent speed within the studied velocity range. The CFD modeling results were consistent with the experimental abatement of methylene blue (MB), although the model slightly overestimated MB degradation because it did not fully account for the consumption of OH radicals from byproducts generated in the MB decomposition processes. The OH radical... [more]
Snapse: A Visual Tool for Spiking Neural P Systems
Aleksei Dominic C. Fernandez, Reyster M. Fresco, Francis George C. Cabarle, Ren Tristan A. de la Cruz, Ivan Cedric H. Macababayao, Korsie J. Ballesteros, Henry N. Adorna
October 14, 2021 (v1)
Keywords: membrane computing, spiking neural P systems, visual simulator
Spiking neural P (SN P) systems are models of computation inspired by spiking neurons and part of the third generation of neuron models. SN P systems are equivalent to Turing machines and are able to solve computationally hard problems using a space-time trade-off. Research in SN P systems theory is especially active, more so in recent years as more efforts are directed towards their real-world applications. Usually, SN P systems are represented visually as a directed graph and simulated through mainly text-based simulations or tables. Thus, there is a need for tools that can simulate and create SN P Systems in a visual and easy-to-use manner. Snapse is such a tool which aims to hasten the speed and ease at which researchers may create and experiment with SN P systems. Furthermore, visual tools such as Snapse can help further bring SN P systems outside of theoretical computer science.
A Discrete Element Method Study of Solids Stress in Cylindrical Columns Using MFiX
Filippo Marchelli, Renzo Di Felice
October 11, 2021 (v1)
Keywords: Coulomb friction force, discrete element method, Janssen effect, solids pressure
Friction phenomena play a key role in discrete element method (DEM) modeling. To analyze this aspect, we employed the open-source program MFiX to perform DEM simulations of cylindrical vertical columns filled with solid particles. These are still associated with and described by the pioneering model by the German engineer H.A. Janssen. By adapting the program’s code, we were able to gather numerous insights on the stress distribution within the solids. The column was filled with different amounts of solids and, after the system had stabilized, we assessed the pressure in the vertical and radial directions and the distribution of the friction force for all particles. An analysis of the bottom pressure for varying particle loads allowed us to infer that the program can correctly predict the expected asymptotical behavior. After a detailed assessment of the behavior of a single system, we performed a sensitivity analysis taking into account several of the variables employed in the simulat... [more]
Modeling the Spread of Epidemics Based on Cellular Automata
Jindong Dai, Chi Zhai, Jiali Ai, Jiaying Ma, Jingde Wang, Wei Sun
October 11, 2021 (v1)
Keywords: cellular automata, dynamic simulation, mathematical model, process system engineering
Mathematical modeling is a powerful tool to study the process of the spread of infectious diseases. Among various mathematical methods for describing the spread of infectious diseases, the cellular automaton makes it possible to explicitly simulate both the spatial and temporal evolution of epidemics with intuitive local rules. In this paper, a model is proposed and realized on a cellular automata platform, which is applied to simulate the spread of coronavirus disease 2019 (COVID-19) for different administrative districts. A simplified social community is considered with varying parameters, e.g., sex ratio, age structure, population movement, incubation and treatment period, immunity, etc. COVID-19 confirmation data from New York City and Iowa are adopted for model validation purpose. It can be observed that the disease exhibits different spread patterns in different cities, which could be well accommodated by this model. Then, scenarios under different control strategies in the next... [more]
Hydrodynamic and Mass Transfer in the Desorption Process of CO2 Gas in a Packed-Bed Stripper
Pao Chi Chen, Ming-Wei Yang, Yan-Lin Lai
September 22, 2021 (v1)
Keywords: hydrodynamic, mass transfer, stripper
A lab-scale packed-bed stripper containing Dixon rings was used to explore the effects of the process variables on the hydrodynamics and mass-transfer in a stripper using a mixed solvent loaded CO2. The variables are the liquid flow rate, reboiler temperature, and amine concentration, and the hydrodynamic and mass-transfer data can be determined using different models. In the case of hydrodynamics, the dimensionless pressure drop at the flooding point and the total pressure drop were explored first. In the case of mass-transfer, the correlation of the mass-transfer coefficient and the parameter importance were also observed. In addition, the number of plates per meter can be compared with the Dixon rings manufacturer. Finally, the performances of a mixed solvent and monoethanolamine (MEA) solvent were also discussed.
Numerical and Experimental Investigation on Key Parameters of the Respimat® Spray Inhaler
Yi Ge, Zhenbo Tong, Renjie Li, Fen Huang, Jiaqi Yu
September 22, 2021 (v1)
Keywords: parameters of aerosol, plume geometry, spray inhaler, volume of fluid (VOF) method
Respimat®Soft MistTM is a newly developed spray inhaler. Different from traditional nebulizers, metered-dose inhalers, and dry powder inhalers, this new type of inhaler can produce aerosols with long duration, relatively slow speed, and a high content of fine particles. Investigating the effect of the key geometric parameters of the device on the atomization is of great significance for generic product development and inhaler optimization. In this paper, a laser high-speed camera experimental platform is built, and important parameters such as the geometric pattern and particle size distribution of the Respimat®Soft MistTM are measured. Computational fluid dynamics (CFD) and the volume of fluid method coupled with the Shear Stress Transport (SST) k-ω turbulence model are applied to simulate the key geometric parameters of the device. The effects of geometric parameters on the spray velocity distribution and geometric pattern are obtained. The angle of flow collision, the sphere size of... [more]
Static and Dynamic Analysis of a 6300 KN Cold Orbital Forging Machine
Zhiqiang Gu, Mingzhang Chen, Chaoyang Wang, Wuhao Zhuang
August 2, 2021 (v1)
Keywords: cold orbital forging, dynamic model, experimental analysis, finite element analysis, machine vibration, numerical simulation, static analysis, theoretical analysis
In cold orbital forging (COF) processes, large stress, displacement and vertical vibration of the COF machine are bad for the quality of the part and the fatigue life of the COF machine. It is necessary to investigate the static and dynamic performance of the COF machine and provide methods for reducing the stress, displacement and vertical vibration of the COF machine. In this paper, finite element analysis, theoretical analysis, numerical simulation and experimental analysis were applied to study the static and dynamic performance of a 6300 KN COF machine. The static and dynamic analyses were verified effectively by carrying out strain and vertical vibration test experiments. In the static analysis, the large stress and displacement positions of the COF machine were mainly distributed near the working table and the junction between the working table and the column. Large stress and displacement will be bad for the quality of the part and the fatigue life of the COF machine. Structura... [more]
A Model of Transport of Particulate Biomass in a Stream of Fluid
Tomasz Reguła, Jarosław Frączek, Jakub Fitas
August 2, 2021 (v1)
Keywords: air stream, Modelling, particle motion, pneumatic separation, two-phase mixtures
The motion of a solid particle introduced into a stream of fluid is a crucial problem in the contexts of pneumatic transport and the purification and separation of non-uniform mixtures. However, the complexity of the underlying equations of motion enforces the creation of semi-empirical models. Therefore, analysis of particle motion in a pneumatic channel was performed. To reduce the number of independent variables, several simplifying assumptions were made in regard to both the particle and the stream. The resulting model provides trajectory equations for a particle introduced into the stream at given values of the initial angle and initial velocity, which are then solved using numerical integration methods. A hodograph function was formulated on the basis of the Runge−Kutta and NDFs methods to test the correctness of the solutions under various initial parameters and to provide a universal method of solving the equations of motion. To verify the model, terminal velocities were measur... [more]
Mixing of Particles in a Rotating Drum with Inclined Axis of Rotation
Parag Widhate, Haiping Zhu, Qinghua Zeng, Kejun Dong
July 29, 2021 (v1)
Keywords: discrete element method, Mixing, rotating drum
Various experimental and numerical studies have been carried out to study the mixing processes inside rotating drums with a horizontal axis of rotation in the past, but little effort has been made to investigate the rotating drums with an inclined axis of rotation, though such inclined drums exist in industrial waste management, food processing, power and pharmaceutical industries. To fill this gap, in this work, the discrete element method was used to study the mixing phenomena of a rotating drum for different angles of inclination from 0° to 15°. It was found that for inclined rotating drums, the whole bed Lacey mixing index is higher than that for the horizontal drum by 7.2% when the angle of inclination is 10°. The mixing index is related to the area ratio of the active region to the whole bed and volumetric fill. Increase in volumetric fill would lead to the decrease of the mixing index. The mixing index and area ratio exhibit similar patterns along the length of the drum for diff... [more]
Comparative Study on CFD Turbulence Models for the Flow Field in Air Cooled Radiator
Chao Yu, Xiangyao Xue, Kui Shi, Mingzhen Shao, Yang Liu
July 29, 2021 (v1)
Keywords: Computational Fluid Dynamics, engine compartment, heat transfer, turbulent model, vortex
This paper compares the performances of three Computational Fluid Dynamics (CFD) turbulence models, Reynolds Average Navier-Stokes (RANS), Detached Eddy Simulation (DES), and Large Eddy Simulation (LES), for simulating the flow field of a wheel loader engine compartment. The distributions of pressure fields, velocity fields, and vortex structures in a hybrid-grided engine compartment model are analyzed. The result reveals that the LES and DES can capture the detachment and breakage of the trailing edge more abundantly and meticulously than RANS. Additionally, by comparing the relevant calculation time, the feasibility of the DES model is proved to simulate the three-dimensional unsteady flow of engine compartment efficiently and accurately. This paper aims to provide a guiding idea for simulating the transient flow field in the engine compartment, which could serve as a theoretical basis for optimizing and improving the layout of the components of the engine compartment.
Flow Ripple Reduction of Axial-Piston Pump by Structure Optimizing of Outlet Triangular Damping Groove
Haocen Hong, Chunxiao Zhao, Bin Zhang, Dapeng Bai, Huayong Yang
July 29, 2021 (v1)
Keywords: axial-piston pump, flow ripple reduction, structure optimizing method, triangular damping groove
The triangular damping groove on the valve plate can effectively reduce the discharge flow ripple of an axial piston pump, which structural parameters will directly affect the pump’s dynamic characteristics. Herein, a multi-parameter data-based structure optimizing method of the triangular damping groove is investigated using numerical models and simulation results. The mathematical models of a nine-piston pump are proposed and developed by MATLAB/Simulink, and the simulation results are verified by experimental results. Then, the effects of width angle and depth angle on discharge flow are analyzed. Based on the analysis of groove parameters, an optimizing index, which considering the time domain characteristics of discharge flow, is proposed. As results show, comparing with the initial specific groove structure, the amplitude of flow ripple is reduced from 14.6% to 9.8% with the optimized structure. The results demonstrate that the outlet flow ripple can be significantly reduced by t... [more]
Influence of the Gas Bubble Size Distribution on the Ladle Stirring Process
Mengkun Li, Lintao Zhang
July 29, 2021 (v1)
Keywords: bubble diameter, ladle bottom stirring, ladle refining, numerical simulation, secondary metallurgy
This work aims at figuring out the influence of gas bubble size distribution on the ladle stirring process. The work is conducted through three-dimensional (3D) numerical simulation based on the finite volume method. Mesh sensitivity test and the cross-validation are performed to ensure the results are mesh independent and the numerical set-up is correct. Two distributions, uniform and Log-normal function, are investigated under different gas flow rates and number of porous plugs. The results indicate that the results, e.g., the axial velocity and the area of the slag eye, have little difference for low flow rate. The difference becomes dominant whilst the flow rate is increasing, such as 600 NL/min. The Log-normal function bubble size distribution gives a larger axial velocity and a smaller slag eye area compared to the uniform bubble size distribution. This work indicated that, at a higher flow rate, the Log-normal function is a better choice to predict the melt behavior and the slag... [more]
Simulation of Prosopis juliflora Air Gasification in Multistage Fluidized Process
Maryem Dhrioua, Walid Hassen, Lioua Kolsi, Kaouther Ghachem, Chemseddine Maatki, Mohamed Naceur Borjini
July 29, 2021 (v1)
Keywords: Aspen Plus, fluidized-bed, multistage gasifier
A multistage atmospheric fluidized bed gasifier was developed using the Aspen Plus simulation process. The innovative gasification reactor aims to yield a high-quality product gas as it conducts pyrolysis, combustion, and reduction in different zones. In addition, it uses gas as a heat carrier and has a fluidized char bed in the reduction zone to enhance the in-situ tar reduction. In order to study the feasibility of the gasifier, an evaluation of the product gas and the process efficiency is required. The proposed model was based on the reaction rates and hydrodynamic parameters of the bubbling bed. Four different stages were initially considered in the simulation process: decomposition of the feed, partial volatile combustion, char reduction, and gas solid separation. The gasification reactor was operated over a temperature range of 800−1000 °C and an isothermal combustion reactor was operated at 1000 °C. In addition, the air to biomass mass ratio was varied from 0.2 to 0.5. It has b... [more]
Computational Study in Bottom Gas Injection Using the Conservative Level Set Method
Jorge E. Rivera-Salinas, Karla M. Gregorio-Jáuregui, Alejandro Cruz-Ramírez, Víctor H. Gutierréz-Pérez, José A. Romero-Serrano, Seydy L. Olvera-Vazquez, Heidi A. Fonseca-Florido, Carlos A. Ávila-Orta
July 28, 2021 (v1)
Keywords: bottom gas injection, bubble formation, conservative level set method, free surface
This paper presents a computational study on bottom gas injection in a cylindrical tank. The bubble formation at submerged orifices, bubble rising, and interactions between bubbles and bubbles with the free surface were studied using the conservative level set method (CLSM). Since the gas injection is an important technique in various fields and this process is quite complicated, the scenario was chosen to quantify the efficacy of the CLSM to describe the gas-liquid complex interactions with fast changes in the surface tension force and buoyancy force. The simulation accuracy is verified with the grid convergence index (GCI) approach and Richardson Extrapolation (RE) and is validated by comparing the numerical results with experimental observations, theoretical equations, and published data. The results show that the CLSM accurately reproduces the bubble formation frequency, and that it can handle complicated bubble shapes. Moreover, it captures the challenging phenomena of interaction... [more]
CFD Modeling and Experimental Validation of an Alkaline Water Electrolysis Cell for Hydrogen Production
Jesús Rodríguez, Ernesto Amores
July 26, 2021 (v1)
Keywords: alkaline water electrolysis, CFD analysis, Energy Storage, green hydrogen, numerical simulation, polarization curve, Renewable and Sustainable Energy, void fraction
Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis, its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard, a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature, electrolyte conductivity, and electrode-diaphragm distance. For all cases, the model fits very well with the experimental data with an error of less than 1% for the po... [more]
Numerical Simulation Analysis of Main Structural Parameters of Hydrocyclones on Oil-Gas Separation Effect
Yong Li, Junrong Wang, Hui Ji, Ouyang Li, Songlin Nie
July 19, 2021 (v1)
Keywords: computational fluid dynamics (CFD), hydrocyclone, oil-gas separation, separation performance, structural parameters
Gas pollution in marine lubricating oil systems is harmful to the normal operation of a ship, and is one of the main reasons for the decline of the performance of lubricating oil. In this research, a classic 75 mm hydrocyclone was selected as the oil−gas separation device. A hydrocyclone is a device that uses the density difference of the two-phase flow to separate the dispersed phase in the centrifugal force field. Compared with ordinary active oil−gas separators, hydrocyclones do not require additional power devices. After establishing the physical model of the hydrocyclone, the distribution characteristics of the flow field and oil−gas two-phase flow separation performance of the hydrocyclone were studied using computational fluid dynamics (CFD) technology. The influence of vortex finder diameter, vortex finder length, spigot diameter, cylindrical-part length, and cone angle on the oil−gas separation performance of the hydrocyclone were investigated. It was found that the vortex fin... [more]
Eulerian Multiphase Simulation of the Particle Dynamics in a Fluidized Bed Opposed Gas Jet Mill
Dyrney Araújo dos Santos, Shivam Baluni, Andreas Bück
July 19, 2021 (v1)
Keywords: comminution, compressible flow, granular temperature, OpenFOAM, particle velocity, turbulent flow
The compressible and turbulent gas−solid multiphase flow inside a fluidized bed opposed jet mill was systematically investigated through numerical simulations using the Euler−Euler approach along with the kinetic theory of granular flow and frictional models. The solid holdup and nozzle inlet air velocity effects on the gas−solid dynamics were assessed through a detailed analysis of the time-averaged volume fraction, the time-averaged velocity, the time-averaged streamlines, and the time-averaged vector field distributions of both phases. The simulated results were compared with the experimental observations available in the literature. The numerical simulations contributed to a better understanding of the particle−flow dynamics in a fluidized bed opposed gas jet mill which are of fundamental importance for the milling process performance.
Numerical Simulation on the Brake Effect of FAC-EMBr and EMBrRuler in the Continuous Casting Mold
Zhuang Li, Lintao Zhang, Yanming Bao, Danzhu Ma
July 19, 2021 (v1)
Keywords: continuous casting, electromagnetic brake, mold
The brake effect of the freestanding adjustable combination electromagnetic brake (FAC-EMBr) and EMBr ruler on the behavior of molten steel flow and the level fluctuation were investigated with the numerical method. The effects of the horizontal magnetic pole position (EMBr ruler), magnetic induction intensity, and casting speed on two types of electromagnetic brakes were studied. The numerical simulation results show that the magnetic field caused by the EMBr ruler is mainly distributed under the submerged entry nozzle (SEN), and it is very weak nearby the meniscus area. After the FAC-EMBr is applied, the magnetic field is mainly distributed in the area below the submerged entry nozzle, the upper roll region, and in the meniscus region. The application of the electromagnetic brake can effectively suppress the impact of the jet and decrease the molten steel velocity in the meniscus area. The brake effect of the EMBr ruler on the behavior of the molten steel flow and the level fluctuati... [more]
Numerical Simulation of Performance of an Air−Water Separator with Corrugated Plates for Marine Diesel Engines
Jie Tian, Yan Chen, Zheshu Ma
July 19, 2021 (v1)
Keywords: air–water separator, corrugated plate, discrete phase model, pressure drop, separation efficiency
For low speed diesel engines under severe ocean conditions, high efficiency air−water separators must be equipped to separate excess moisture contained in the air and reduce the corrosion. Optimal design of air−water separator is an indispensable part in the development of marine main engines. In view of the complex gas−liquid two-phase turbulent motion within an air−water separator with corrugated plates, a mathematical model is established and numerical simulations of flow field, droplet trajectory and secondary transport are realized. The separation efficiency and pressure drop of the air−water separator under different structure parameters and different working conditions are studied. The results show that reducing the spacing of corrugated plate is helpful to improve the separation efficiency. The bending and hydrophobic hooks of the corrugated channel are important to improve the separation efficiency. The separation of droplet is mainly concentrated on the first two stages of th... [more]
Modeling and Design of the Automatic Pressure Regulating Valve in the Foam Firefighting System
Zhijun Yang, Hongjun Chen, Lifang He, Xikun Wang
July 19, 2021 (v1)
Keywords: automatic pressure balancing valve, foam firefighting system, in-line balanced pressure (ILBP) proportioner, mathematical model, Simulation
This paper presents a novel design of the automatic pressure balancing valve, used in the in-line balanced pressure (ILBP) proportioner for the foam firefighting system, at a required percentage of solution. Featured in a four-chamber configuration with a double-acting diaphragm actuator, it can automatically maintain the foam concentrate pressure with the pressure in the supply water pipeline, within a precision level of 0.02 MPa (or 1.3%), under the design operating condition. The static characteristics at the equilibrium state have been discussed in terms of poppet displacement with reference to the geometrical dimensions and operating pressures of the valve. The dynamic response of the valve during the startup has been examined through building the mathematical model of the forces on the valve and solving it numerically using MATLAB. The results show that the response time of the valve is always less than 0.01 s, which fully satisfies the stability and hysteresis requirement. The p... [more]
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