scholarly journals Nanofluid-Powered Dual-Fluid Photovoltaic/Thermal (PV/T) System: Comparative Numerical Study

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 775 ◽  
Author(s):  
M. Hussain ◽  
Jin-Hee Kim ◽  
Jun-Tae Kim
Keyword(s):  
Experimental Validation ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Numerical Models ◽  
Metal Oxide Nanoparticles ◽  
Transfer Enhancement ◽  
Ansys Fluent ◽  
Fluctuating Irradiance ◽  
Explicit Dynamic ◽  
T System

A limited number of studies have examined the effect of dual-fluid heat exchangers used for the cooling of photovoltaic (PV) cells. The current study suggests an explicit dynamic model for a dual-fluid photovoltaic/thermal (PV/T) system that uses nanofluid and air simultaneously. Mathematical modeling and a CFD simulation were performed using MATLAB® and ANSYS FLUENT® software, respectively. An experimental validation of the numerical models was performed using the results from the published study. Additionally, to identify the optimal nanofluid type for the PV/T collector, metal oxide nanoparticles (CuO, Al2O3, and SiO2) with different concentrations were dispersed in the base fluid (water). The results revealed that the CuO nanofluid showed the highest thermal conductivity and the best thermal stability compared to the other two nanofluids evaluated herein. Furthermore, the influence of CuO nanofluid in combination with air on the heat transfer enhancement is investigated under different flow regions such as laminar, transition, and turbulent. Using a CuO nanofluid plus air and water plus air the total equivalent efficiency was found to be 90.3% and 79.8%, respectively. It is worth noting that the proposed models could efficiently simulate both single and dual-fluid PV/T systems even under periods of fluctuating irradiance.

scholarly journals Prediction of Pollutants Emissions in a CFM56-3 Combustor, Using Large Eddy Simulation

2020 ◽  
Author(s):  
Inês Isabel Ascensão Costa Morão ◽  
Francisco Miguel Ribeiro Proença Brojo
Keyword(s):  
Large Eddy Simulation ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Jet Fuels ◽  
Cad Model ◽  
Commercial Software ◽  
Ansys Fluent ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Detailed Chemical

In the present work a CFD simulation was performed using a CFM56-3 combustor.   It was intended to simulate the combustion and emission of pollutants (CO2, CO, UHC and NOx) from the different jet fuels ( Jet A, Jet B and TS-1), when burning these through ICAO’s LTO cycle. Being this a continuity study, the CAD model of CFM56-3 made by Oliveira [5] was used. The mesh was constructed with HELYX-OS software and the numerical study was made using the commercial software ANSYS Fluent16.2. It can be concluded, amongst all the fuels simulated that increasing the power produces higher NOx. There was also an erratic behaviour in the emissions of UHC and CO results, because an empiric model was used and not a detailed chemical model. Keywords: Jet Fuels, ANSYS Fluent, Pollutants emissions, ICAO’s LTO cycle, CFM56-3

scholarly journals CFD simulation of flow behind overflooded obstacle

2018 ◽  
Vol 66 (4) ◽  
pp. 448-456
Author(s):  
Yvetta Velísková ◽  
Zdeněk Chára ◽  
Radoslav Schügerl ◽  
Renáta Dulovičová
Keyword(s):  
Velocity Profile ◽  
Cfd Simulation ◽  
Numerical Models ◽  
Measured Data ◽  
Ansys Fluent ◽  
Laboratory Flume ◽  
Rans Models ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Models

Abstract This paper deals with studying of two topics – measuring of velocity profile deformation behind a over-flooded construction and modelling of this velocity profile deformation by computational fluid dynamics (CFD). Numerical simulations with an unsteady RANS models - Standard k-ε, Realizable k-ε, Standard k-ω and Reynolds stress models (ANSYS Fluent v.18) and experimental measurements in a laboratory flume (using ADV) were performed. Results of both approaches showed and affirmed presence of velocity profile deformation behind the obstacle, but some discrepancies between the measured and simulated values were also observed. With increasing distance from the obstacle, the differences between the simulation and the measured data increase and the results of the numerical models are no longer usable.

Numerical Simulation for Falling Film Thickness around Horizontal Tube in MVC and MED Evaporators

2020 ◽  
Vol 1008 ◽  
pp. 139-150
Author(s):  
Alaa A. Ibrahim ◽  
Hassan E.S. Fath ◽  
Mona G. Ibrahim
Keyword(s):  
Mass Transfer ◽  
Film Thickness ◽  
Heat And Mass Transfer ◽  
Numerical Study ◽  
Numerical Models ◽  
Thickness Distribution ◽  
Horizontal Tube ◽  
Falling Film ◽  
Ansys Fluent ◽  
Intertube Space

Falling film on horizontal tube evaporators, of both Mechanical Vapor Compression (MVC) and the Multi-Effect Distillation (MED) desalination systems, plays an important role in the heat and mass transfer (evaporation) and accordingly the systems productivity. Falling film thickness is mainly influenced by the intertube space, circumferential angle and the film’s Reynolds number. This paper presents two-dimensional numerical study of falling film thickness around horizontal tube in MVC and MED evaporators. The study is based on computational fluid dynamics (CFD) using volume of fraction (VOF) as a multi-phase technique in ANSYS Fluent. The numerical model is developed in order to study the heat and mass transfer charactristics, the liquid falling film behaviour and thickness distribution around circular horizontal. Four CFD study cases are developed to simulate the falling film behaviour at circumferential angle range from 150 to 1650 with inter-tube spacing of 10 mm, 16 mm, 33 mm and 40 mm and for constant value of flow rate and at the same surrounding conditions. Simulations are conducted using a domain of only two tubes with 20 mm outer diameter.The results from the numerical models are compared with the published experimental correlations, showing a comparatively reasonable agreement. In addition, a parametric study is carried out to illustrate the effect of flow Reyonlds number (Re) and intertube space on the average circumferential film thickness and heat transfer rates.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

2006 ◽  
Author(s):  
Michael Maurer ◽  
Jens von Wolfersdorf ◽  
Michael Gritsch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
High Reynolds Numbers ◽  
High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

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