scholarly journals Using computational fluid dynamics to describe H2S mass transfer across the water–air interface in sewers

2019 ◽  
Vol 79 (10) ◽  
pp. 1934-1946 ◽  
Author(s):  
Katharina Teuber ◽  
Tabea Broecker ◽  
Thomas Ruby Bentzen ◽  
Dietmar Stephan ◽  
Gunnar Nützmann ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Ph Value ◽  
Three Dimensional ◽  
Test Case ◽  
Two Phase ◽  
The Past ◽  
Time Flow ◽  
Flow Velocities

Abstract For the past 70 years, researchers have dealt with the investigation of odour in sewer systems caused by hydrogen sulphide formations and the development of approaches to describe it. The state-of-the-art models are one-dimensional. At the same time, flow and transport phenomena in sewers can be three-dimensional, for example the air flow velocities in circular pipes or flow velocities of water and air in the reach of drop structures. Within the past years, increasing computational capabilities enabled the development of more complex models. This paper uses a three-dimensional two-phase computational fluid dynamics model to describe mass transfer phenomena between the two phases: water and air. The solver has been extended to be capable of accounting account for temperature dependency, the influence of pH value and a conversion to describe simulated air phase concentrations as partial pressure. Its capabilities are being explored in different application examples and its advantages compared to existing models are demonstrated in a highly complex three-dimensional test case. The resulting interH2SFoam solver is a significant step in the direction of describing and analysing H2S emissions in sewers.

scholarly journals Numerical Simulation and Analysis on Spray Drift Movement of Multirotor Plant Protection Unmanned Aerial Vehicle

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2399 ◽  
Author(s):  
Fengbo Yang ◽  
Xinyu Xue ◽  
Chen Cai ◽  
Zhu Sun ◽  
Qingqing Zhou
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Droplet Size ◽  
Wind Field ◽  
Flow Model ◽  
Two Phase Flow ◽  
Plant Protection ◽  
Three Dimensional ◽  
Phase Flow ◽  
Two Phase

In recent years, multirotor unmanned aerial vehicles (UAVs) have become more and more important in the field of plant protection in China. Multirotor unmanned plant protection UAVs have been widely used in vast plains, hills, mountains, and other regions, and become an integral part of China’s agricultural mechanization and modernization. The easy takeoff and landing performances of UAVs are urgently required for timely and effective spraying, especially in dispersed plots and hilly mountains. However, the unclearness of wind field distribution leads to more serious droplet drift problems. The drift and distribution of droplets, which depend on airflow distribution characteristics of UAVs and the droplet size of the nozzle, are directly related to the control effect of pesticide and crop growth in different growth periods. This paper proposes an approach to research the influence of the downwash and windward airflow on the motion distribution of droplet group for the SLK-5 six-rotor plant protection UAV. At first, based on the Navier-Stokes (N-S) equation and SST k–ε turbulence model, the three-dimensional wind field numerical model is established for a six-rotor plant protection UAV under 3 kg load condition. Droplet discrete phase is added to N-S equation, the momentum and energy equations are also corrected for continuous phase to establish a two-phase flow model, and a three-dimensional two-phase flow model is finally established for the six-rotor plant protection UAV. By comparing with the experiment, this paper verifies the feasibility and accuracy of a computational fluid dynamics (CFD) method in the calculation of wind field and spraying two-phase flow field. Analyses are carried out through the combination of computational fluid dynamics and radial basis neural network, and this paper, finally, discusses the influence of windward airflow and droplet size on the movement of droplet groups.

CFD Modelling of Multiphase Flows: An Overview

2003 ◽  
Author(s):  
Rajnish K. Calay ◽  
Arne E. Holdo
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Mathematical Models ◽  
Cfd Modelling ◽  
Two Phase ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Modeling Of Flows

The Computational Fluid Dynamics (CFD) is now increasingly being used for modeling industrial flows, i.e. flows which are multiphase and turbulent. Numerical modeling of flows where momentum, heat and mass transfer occurs at the interface presents various difficulties due to the wide range of mechanisms and flow scenarios present. This paper attempts to provide a summary of available mathematical models and techniques for two-phase flows. Some comments are also made on the models available in the commercially available codes.

Three-Dimensional, Two-Phase Computational Fluid Dynamics Simulations of Alkaline Diaphragm Water Electrolysis Devices

2020 ◽  
Vol MA2020-02 (38) ◽  
pp. 2495-2495
Author(s):  
Joseph Steven Lopata ◽  
Sanggyu Kang ◽  
Hyun-Seok Cho ◽  
Chang Hee Kim ◽  
Sirivatch Shimpalee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Water Electrolysis ◽  
Two Phase ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Simplified two-group two-fluid model for three-dimensional two-phase flow Computational Fluid Dynamics for vertical upward flow

2018 ◽  
Vol 108 ◽  
pp. 503-516 ◽  
Author(s):  
Takashi Hibiki ◽  
Joshua P. Schlegel ◽  
Tetsuhiro Ozaki ◽  
Shuichiro Miwa ◽  
Somboon Rassame
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Three Dimensional ◽  
Phase Flow ◽  
Upward Flow ◽  
Two Phase ◽  
Two Fluid Model ◽  
Two Fluid

Hydrodynamics and Mass Transfer Simulation in Airlift Bioreactor with Settler using Computational Fluid Dynamics

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Oscar M. Hernández-Calderón ◽  
Marcos D. González-Llanes ◽  
Erika Y. Rios-Iribe ◽  
Sergio A. Jiménez-Lam ◽  
Ma.del Carmen Chavez-Parga ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Liquid Velocity ◽  
Fluid Dynamic ◽  
Gas Holdup ◽  
Airlift Bioreactor ◽  
Cfd Modeling ◽  
Two Phase

Abstract In this work, the effect of inlet-gas superficial velocity over the circulation liquid velocity, gas holdup and mass transfer, from an airlift bioreactor with settler were studied by Computational Fluid Dynamics (CFD) modeling and contrasted with experimental results. Multiphase mixture model and κ-ε turbulence model were used to describe the two phases gas-liquid flow pattern in airlift bioreactor. The hydrodynamic parameters such as liquid circulation velocity and gas holdup were computed by solving the governing equations of continuity, moment and turbulence transport using the finite volume method. Global mass transfer coefficient was evaluated through the Higbie’s penetration theory and the two-phase fluid dynamic theory. Comparison between our numerical data and experimental data previously reported in the literature was done. Numerical and experimental data were very close, and the differences found were discussed in terms of the limitations of this study.

Computational Fluid Dynamics Simulation of Direct-Contact Condensation Phenomenon of Vapor Jet in Subcooled Water Tank

2016 ◽  
Vol 2 (4) ◽  
Author(s):  
Yu Ji ◽  
Hao-Chun Zhang ◽  
Yi-Ning Zhang ◽  
Xu-Wei Wang ◽  
Yan Quan
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Direct Contact ◽  
Chemical Engineering ◽  
Dynamics Simulation ◽  
Water Tank ◽  
Two Phase ◽  
Subcooled Water ◽  
Contact Condensation

The direct-contact condensation (DCC) is a significant phenomenon in a nuclear reactor and its balance facilities, together with some chemical engineering systems. DCC occurs when the vapor is ejected from the nozzle, contacts with subcooled water, and condenses at the interface directly. The DCC phenomenon accompanied with the heat transfer and mass transfer will lead to the temperature and pressure fluctuations in the tank, even some accidents under certain conditions. This paper investigates the transport phenomena concerning the DCC in the subcooled water tank using the computational fluid dynamics (CFD) commercial code, ANSYS-FLUENT, in which the DCC process is simulated with the Euler–Euler framework for two-phase flow, and the simplified Hertz–Knudsen–Schrage relation is adopted to model mass transfer. In the simulation, the flow field and temperature profile are derived. Moreover, the shape and size of the plume jet are also investigated.

Sign in / Sign up

Export Citation Format

Share Document