CFD MODELLING AND VALIDATION OF LOSS COEFFICIENTS FOR PENSTOCK BIFURCATIONS IN HYDROPOWER SCHEMES

2018 ◽  
Author(s):  
Kasturi Sukhapure ◽  
Alan Burns ◽  
Tariq Mahmud ◽  
Jake Spooner
Keyword(s):  
Cfd Modelling ◽  
Loss Coefficients

Inundation Analysis in Urban Area Considering of Head Loss Coefficients at Surcharged Manholes

2015 ◽  
Vol 48 (2) ◽  
pp. 127-136
Author(s):  
Won Lee ◽  
◽  
Jung Soo Kim ◽  
Sei Eui Yoon
Keyword(s):  
Urban Area ◽  
Head Loss ◽  
Loss Coefficients

scholarly journals CFD modelling of an animal occupied zone using an anisotropic porous medium model with velocity depended resistance parameters

2021 ◽  
Vol 181 ◽  
pp. 105950
Author(s):  
E. Moustapha Doumbia ◽  
David Janke ◽  
Qianying Yi ◽  
Thomas Amon ◽  
Martin Kriegel ◽  
...  
Keyword(s):  
Porous Medium ◽  
Cfd Modelling ◽  
Medium Model ◽  
Anisotropic Porous Medium ◽  
Porous Medium Model ◽  
Occupied Zone

scholarly journals Turbulence model performance for ventilation components pressure losses

2021 ◽  
Author(s):  
Karsten Tawackolian ◽  
Martin Kriegel
Keyword(s):  
Reynolds Number ◽  
Turbulence Model ◽  
Pressure Loss ◽  
Low Reynolds Number ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Test Case ◽  
Pressure Losses ◽  
Loss Coefficients ◽  
Near Wall

AbstractThis study looks to find a suitable turbulence model for calculating pressure losses of ventilation components. In building ventilation, the most relevant Reynolds number range is between 3×104 and 6×105, depending on the duct dimensions and airflow rates. Pressure loss coefficients can increase considerably for some components at Reynolds numbers below 2×105. An initial survey of popular turbulence models was conducted for a selected test case of a bend with such a strong Reynolds number dependence. Most of the turbulence models failed in reproducing this dependence and predicted curve progressions that were too flat and only applicable for higher Reynolds numbers. Viscous effects near walls played an important role in the present simulations. In turbulence modelling, near-wall damping functions are used to account for this influence. A model that implements near-wall modelling is the lag elliptic blending k-ε model. This model gave reasonable predictions for pressure loss coefficients at lower Reynolds numbers. Another example is the low Reynolds number k-ε turbulence model of Wilcox (LRN). The modification uses damping functions and was initially developed for simulating profiles such as aircraft wings. It has not been widely used for internal flows such as air duct flows. Based on selected reference cases, the three closure coefficients of the LRN model were adapted in this work to simulate ventilation components. Improved predictions were obtained with new coefficients (LRNM model). This underlined that low Reynolds number effects are relevant in ventilation ductworks and give first insights for suitable turbulence models for this application. Both the lag elliptic blending model and the modified LRNM model predicted the pressure losses relatively well for the test case where the other tested models failed.

scholarly journals CFD Modelling of a Hydrogen/Air PEM Fuel Cell with a Serpentine Gas Distributor

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 564
Author(s):  
Alessandro d’Adamo ◽  
Matteo Riccardi ◽  
Massimo Borghi ◽  
Stefano Fontanesi
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Active Surface ◽  
Reaction Rates ◽  
Transport Processes ◽  
Proton Exchange ◽  
Sustainable Mobility ◽  
Cfd Modelling ◽  
Gas Distributor

Hydrogen-fueled fuel cells are considered one of the key strategies to tackle the achievement of fully-sustainable mobility. The transportation sector is paying significant attention to the development and industrialization of proton exchange membrane fuel cells (PEMFC) to be introduced alongside batteries, reaching the goal of complete de-carbonization. In this paper a multi-phase, multi-component, and non-isothermal 3D-CFD model is presented to simulate the fluid, heat, and charge transport processes developing inside a hydrogen/air PEMFC with a serpentine-type gas distributor. Model results are compared against experimental data in terms of polarization and power density curves, including an improved formulation of exchange current density at the cathode catalyst layer, improving the simulation results’ accuracy in the activation-dominated region. Then, 3D-CFD fields of reactants’ delivery to the active electrochemical surface, reaction rates, temperature distributions, and liquid water formation are analyzed, and critical aspects of the current design are commented, i.e., the inhomogeneous use of the active surface for reactions, limiting the produced current and inducing gradients in thermal and reaction rate distribution. The study shows how a complete multi-dimensional framework for physical and chemical processes of PEMFC can be used to understand limiting processes and to guide future development.

CFD modelling of supercritical water reforming of glycerol for hydrogen production

2021 ◽  
Author(s):  
Ionela-Dorina Dumbrava ◽  
Calin-Cristian Cormos ◽  
Arpad Imre-Lucaci ◽  
Ana-Maria Cormos
Keyword(s):  
Hydrogen Production ◽  
Supercritical Water ◽  
Cfd Modelling
Sign in / Sign up

Export Citation Format

Share Document