scholarly journals Study of the Impact of PV-Thermal and Nanofluids on the Desalination Process by Flashing

2020 ◽  
Vol 3 (1) ◽  
pp. 10
Author(s):  
Samuel Sami
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Solar System ◽  
Solar Radiation ◽  
Base Fluid ◽  
Control Volume ◽  
Proposed Model ◽  
Finite Control ◽  
The Impact ◽  
Mathematical And Numerical Modeling

In this study, a mathematical and numerical modeling of the photovoltaic (PV)-thermal solar system to power the multistage flashing chamber process is presented. The proposed model was established after the mass and energy conservation equations written for finite control volume were integrated with properties of the water and nanofluids. The nanofluids studied and presented herein are Ai2O3, CuO, Fe3O4, and SiO2. The multiple flashing chamber process was studied under various conditions, including different solar radiation levels, brine flows and concentrations, and nanofluid concentrations as well as flashing chamber temperatures and pressures. Solar radiation levels were taken as 500 w/m2, 750 w/m2, 1000 w/m2, and finally, 1200 w/m2. The nanofluid volumetric concentrations considered varied from 1% to 20%. There is clear evidence that the higher the solar radiation, the higher the flashed flow produced. The results also clearly show that irreversibility is reduced by using nanofluid Ai2O3 at higher concentrations of 10% to 20% compared to water as base fluid. The highest irreversibility was experienced when water was used as base fluid and the lowest irreversibility was associated with nanofluid SiO2. The irreversibility increase depends upon the type of nanofluid and its thermodynamic properties. Furthermore, the higher the concentration (e.g., from 10% to 20% of Ai2O3), the higher the availability at the last flashing chamber. However, the availability is progressively reduced at the last flashing chamber. Finally, the predicted results compare well with experimental data published in the literature.

Numerical Modeling of Reflux Solar Receivers

1993 ◽  
Vol 115 (2) ◽  
pp. 93-100 ◽  
Author(s):  
R. E. Hogan
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Energy Transfer ◽  
Thermal Resistance ◽  
Numerical Models ◽  
Control Volume ◽  
Operating Conditions ◽  
Working Fluid ◽  
Detailed Model ◽  
Finite Control

Using reflux solar receivers to collect solar energy for dish-Stirling electric power generation systems is presently being investigated by several organizations, including Sandia National Laboratories, Albuquerque, N. Mex. In support of this program, Sandia has developed two numerical models describing the thermal performance of pool-boiler and heat-pipe reflux receivers. Both models are applicable to axisymmetric geometries and they both consider the radiative and convective energy transfer within the receiver cavity, the conductive and convective energy transfer from the receiver housing, and the energy transfer to the receiver working fluid. The primary difference between the models is the level of detail in modeling the heat conduction through the receiver walls. The more detailed model uses a two-dimensional finite control volume method, whereas the simpler model uses a one-dimensional thermal resistance approach. The numerical modeling concepts presented are applicable to conventional tube-type solar receivers, as well as to reflux receivers. Good agreement between the two models is demonstrated by comparing the predicted and measured performance of a pool-boiler reflux receiver being tested at Sandia. For design operating conditions, the receiver thermal efficiencies agree within 1 percent and the average receiver cavity temperature within 1.3 percent. The thermal efficiency and receiver temperatures predicted by the simpler thermal resistance model agree well with experimental data from on-sun tests of the Sandia reflux pool-boiler receiver. An analysis of these comparisons identifies several plausible explanations for the differences between the predicted results and the experimental data.

Experimental and Numerical Investigation of Dynamic Impact on Universal Breakaway Steel Post

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Mojdeh A. Pajouh ◽  
John D. Reid
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Dynamic Impact ◽  
Roadside Safety ◽  
Impact Performance ◽  
Component Testing ◽  
Long Span ◽  
Finite Element Package ◽  
The Impact

Abstract A closed guardrail system, known as “bullnose” guardrail system, was previously developed to prevent out-of-control vehicles from falling into the elephant trap. The bullnose guardrail system originally used Controlled Release Terminal (CRT) wood posts to aid in the energy absorption of the system. However, the use of CRT had several drawbacks such as grading and the need for regular inspections. Universal Breakaway Steel Post (UBSP) was then developed by the researchers at Midwest Roadside Safety Facility as a surrogate for CRT. In this study, the impact performance of UBSP on the weak-axis and strong-axis was studied through numerical modeling and component testing (bogie testing). A numerical model was developed using an advanced finite element package LS-DYNA to simulate the impact on UBSP. The numerical results were compared to experimental data. Further research on soil models was recommended. The numerical model will be used to investigate other applications for UBSP such as the Midwest Guardrail System (MGS) long span system, guardrail end terminal designs, or crash cushions.

Empirical estimation of engine-integration noise for high bypass ra-tio turbofan engines

2021 ◽  
Vol 263 (2) ◽  
pp. 4511-4519
Author(s):  
Incheol Lee ◽  
Yingzhe Zhang ◽  
Dakai Lin
Keyword(s):  
Experimental Data ◽  
Pressure Side ◽  
Empirical Estimation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Turbofan Engines ◽  
Proposed Model ◽  
The Impact ◽  
Bypass Ratio ◽  
Good Agreement

To investigate the impact of installation on jet noise from modern high-bypass-ratio turbofan engines, a model-scale noise experiment with a jet propulsion system and a fuselage model in scale was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as wing positions relative to the tip of the engine nacelle and flap angles, were considered. Based on the analysis of experimental data, an empirical model for the prediction of engine installation noise was proposed. The model comprises two components: one is the interaction be-tween the jet and the pressure side of the wing, and the other is the interaction between the jet and the flap tip. The interaction between the jet and the pressure side of the wing contributes to the noise at the low frequencies (≤ 1.5 kHz), and the interaction between the jet and the flap tip con-tributes to the noise at the high frequencies. The proposed model showed a good agreement with the experimental data.

Analysis of perforation process into concrete/metal targets by rigid projectiles

2012 ◽  
Vol 227 (7) ◽  
pp. 1454-1468 ◽  
Author(s):  
N Khazraiyan ◽  
GH Liaghat ◽  
H Khodarahmi ◽  
N Dashtian-Gerami
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Cavity Expansion ◽  
Velocity Range ◽  
Material Models ◽  
Backing Plate ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
The Impact ◽  
Good Agreement

In this article, a semi-analytical model has been developed for perforation of a hard projectile into a single- and two-layer concrete targets. The model is based on the dynamic cavity expansion theory and the reflection of compressive waves from the end of the concrete targets. The effect of friction coefficient is also investigated in the analysis. Numerical modeling of the problem has been performed in LS-DYNA code. Holmquist–Johnson–Cook, plastic kinematic, and rigid material models have been employed for the concrete, the backing plate, and the projectile, respectively. The impact velocity range, considered in this study, is between 300 and 800 m/s. No projectile erosion is considered in this velocity range. The analytical results of the investigation for both single- and two-layer concrete targets are in a good agreement with numerical simulations and experimental data.

scholarly journals Daily predictions of solar radiation utilizing genetic programming techniques

2020 ◽  
Vol 19 (2) ◽  
pp. 900
Author(s):  
Rahima Ummi Kulsum Nadya ◽  
Ali Najah Ahmed ◽  
Abdoulhdi A. Borhana ◽  
N. A. Mardhiah ◽  
Amr El-Shafie ◽  
...  
Keyword(s):  
Wind Speed ◽  
Solar System ◽  
Solar Radiation ◽  
Genetic Programming ◽  
Energy Systems ◽  
Radiation Data ◽  
Proposed Model ◽  
Sunshine Hours ◽  
Programming Techniques ◽  
Radiation Genetic

<span>The solar radiation prediction in Kuala Terengganu located in Terengganu, Malaysia was investigated in this study to improve the solar system design. Solar radiation data and number of parameters such as solar radiation, temperature, humidity, wind speed and sunshine hours were obtained from Malaysian Meteorological Malaysia MMD. In order to predict the solar radiation, Genetic Programming Techniques (GP) models were develop and tested. Two scenarios were considered in this study in order to validate the efficiency of the proposed model. Coefficients of determination (R2) for the solar radiation during training and testing phases were ranged between 0.99402 to 0.98934 for all months of the year. This study confirms the ability of GP to predict solar radiation values precisely and accurately. The predictions from the GP models could enable scientists to locate <br /> and design solar energy systems in Malaysia.</span>

scholarly journals Simulation of the impact of the atmospheric weather state on the efficiency of functioning of solar thermal and power plants

2022 ◽  
Vol 23 (5) ◽  
pp. 86-99
Author(s):  
N. I. Moskalenko ◽  
A. R. Akhmetshin ◽  
Ya. S. Safiullina ◽  
I. R. Dodov ◽  
M. S. Khamidullina
Keyword(s):  
Numerical Modeling ◽  
Solar Radiation ◽  
Atmospheric Aerosol ◽  
Power Plants ◽  
Solar Thermal ◽  
Optical Characteristics ◽  
Molecular Absorption ◽  
Radiation Fluxes ◽  
Equivalent Mass ◽  
The Impact

THE PURPOSE. Determine the impact of the meteorological state of the atmosphere on the efficiency of the functioning of solar thermal and power plants. Modeling the molecular absorption of solar radiation by the atmosphere. Modeling the optical characteristics of the gaseous components of the atmosphere, atmospheric aerosol and clouds.METHODS. A method for numerical modeling of incoming solar radiation fluxes their functioning to determine the efficiency of solar thermal and power plants. The solar fluxes are calculated by stacking layers in a multi-stream approximation, taking into account the multi-tiered cloud cover and the probability of overlapping the sky with clouds. The absorption of radiation by the gaseous phase of the atmosphere is taken into account by the method of equivalent mass in an inhomogeneous atmosphere. The optical characteristics of the dispersed phase of the atmosphere are calculated using the Mie theory.RESULTS. An electronic database has been created on the optical characteristics of the gaseous components of the atmosphere, the optical characteristics of atmospheric aerosol and clouds. The effect of anthropogenic impact on the flux of solar radiation falling on the underlying surface is taken into account. The developed modeling takes into account the effect of humidity on the optical characteristics of atmospheric aerosol and its multicomponent composition, depending on the location of the power plant.CONCLUSION. The information necessary for numerical modeling of meteorological effects on the functioning of solar thermal and power plants is generalized. When calculating solar radiation fluxes, direct illumination of the light-receiving surface by solar radiation, scattered radiation by atmospheric aerosol and clouds are taken into account.

Numerical Modeling of Forced Convection Heat Transfer for Modules Mounted on Circuit Boards

1990 ◽  
Vol 112 (4) ◽  
pp. 333-337 ◽  
Author(s):  
D. Agonafer ◽  
D. F. Moffatt
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Control Volume ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Turbulent Regime ◽  
Circuit Boards ◽  
Commercial Code ◽  
Finite Control ◽  
Effective Use

Numerical simulation of the fluid and heat transfer characteristics of electronic modules mounted on circuit boards is performed using a commercial finite-control-volume code, PHOENICS. The model is used to simulate the experimental data for flow over blocks simulating electronic modules from published sources of data. The Reynolds numbers considered in both studies vary from 1000 to 7000. The numerically computed heat transfer coefficient agreed with the experimental data in the fully developed region within 8 percent. However, the results were quite sensitive to the transverse grid distribution for flow rates in the turbulent regime. Guidelines are suggested in the effective use of the commercial code for such classes of problems.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

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