Numerical Investigation on Optimal Design of Solid Particle Solar Receiver

2007 ◽  
Author(s):  
Huajun Chen ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh ◽  
Greg Kolb ◽  
Nathan Siegel
Keyword(s):  
Solar Radiation ◽  
Solid Particle ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Load Model ◽  
Concentrated Solar Radiation ◽  
Tracing Algorithm ◽  
Solar Receiver ◽  
And Storage

Solar thermo-chemical processes often require high temperatures that can be achieved by direct absorption of solar energy. The solid particle solar receiver can be used to heat ceramic particles that may serve as a heat transfer and storage medium or as a substrate on which chemical reaction may be performed directly. Using solid particles enclosed in a cavity to absorb concentrated solar radiation can provide efficient absorption of concentrated sunlight. In this work, different solid particle solar receiver designs have been investigated by using computation fluid dynamics (CFD) technique. The gas particle flow with the solid particle solar receiver was simulated by using two-way coupled Euler-Lagrange method. The direct illumination energy source that results from incident solar radiation was predicted by a solar load model using a solar ray tracing algorithm. The detailed information to guide the experiment, such as the particle and gas velocity, temperature, particle solid volume fraction, and cavity efficiency under different designs has been analyzed.

CFD Modeling of Gas Particle Flow Within a Solid Particle Solar Receiver

Solar Energy ◽  
2006 ◽  
Author(s):  
Huajun Chen ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh ◽  
Nathan Siegel
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Solid Particle ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Operating Conditions ◽  
Solid Particles ◽  
Particle Flow ◽  
Cfd Modeling ◽  
Solar Receiver

A detailed three dimensional computational fluid dynamics (CFD) analysis on gas-particle flow and heat transfer inside a solid particle solar receiver, which utilizes free-falling particles for direct absorption of concentrated solar radiation, is presented. The two-way coupled Euler-Lagrange method is implemented and includes the exchange of heat and momentum between the gas phase and solid particles. A two band discrete ordinate method is included to investigate radiation heat transfer within the particle cloud and between the cloud and the internal surfaces of the receiver. The direct illumination energy source that results from incident solar radiation was predicted by a solar load model using a solar ray tracing algorithm. Two kinds of solid particle receivers, each having a different exit condition for the solid particles, are modeled to evaluate the thermal performance of the receiver. Parametric studies, where the particle size and mass flow rate are varied, are made to determine the optimal operating conditions. The results also include detailed information for the particle and gas velocity, temperature, particle solid volume fraction, and cavity efficiency.

Performance of Solid Particle Receivers With or Without the Protection of an Aerowindow

2008 ◽  
Author(s):  
Taide Tan ◽  
Yitung Chen ◽  
Zhuoqi Chen
Keyword(s):  
Solar Radiation ◽  
Solid Particle ◽  
Convection Heat Transfer ◽  
Radiation Energy ◽  
Solid Particles ◽  
Wind Effect ◽  
Air Jet ◽  
Optimal Injection ◽  
Solar Receiver ◽  
Prototype Design

A solid particle solar receiver (SPSR) is a direct absorption central receiver that uses solid particles enclosed in a cavity to absorb concentrated solar radiation. However, the existing open aperture lowers the overall efficiency by convection heat transfer. Aerowindows have the potential of increasing the efficiency of an SPSR by reducing convective losses from an open receiver aperture and eliminate reflection, convection and reradiation losses from a comparable glass window. Aerodynamic windows consist of a transparent gas stream, which is injected from an air jet, across the receiver aperture to isolate its interior from the surrounding atmosphere. Even though, the wind conditions may still have important effect on the performance of SPSRs. In the present paper, the wind effect on the performance of an SPSR is investigated numerically. The mass, momentum and energy exchange between the solid particle and air flow are simulated by the two-way coupling Euler-Lagrange method in the realizable k-ε turbulence 3D model. The independence of the calculating domain is studied in order to select a proper domain for the numerical simulation. Solar ray tracing method is employed in calculating the solar radiation energy. The numerical investigation of the performance of the SPSR is focusing on optimizing the prototype design and finding out the best working condition for the SPSR. In order to investigate the influences of the wind speed and wind blowing direction on the performance of the receiver, different wind conditions of and different air jet injection conditions are simulated numerically. The cavity thermal efficiencies are calculated and the optimal injection conditions are analyzed for different wind conditions.

Computational Fluid Dynamics Modeling of Gas-Particle Flow Within a Solid-Particle Solar Receiver

2006 ◽  
Vol 129 (2) ◽  
pp. 160-170 ◽  
Author(s):  
Huajun Chen ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh ◽  
Nathan Siegel
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Solar Radiation ◽  
Solid Particle ◽  
Operating Conditions ◽  
Solid Particles ◽  
Particle Flow ◽  
Outlet Temperature ◽  
Solar Receiver

A detailed three-dimensional computational fluid dynamics (CFD) analysis on gas-particle flow and heat transfer inside a solid-particle solar receiver, which utilizes free-falling particles for direct absorption of concentrated solar radiation, is presented. The two-way coupled Euler-Lagrange method is implemented and includes the exchange of heat and momentum between the gas phase and solid particles. A two-band discrete ordinate method is included to investigate radiation heat transfer within the particle cloud and between the cloud and the internal surfaces of the receiver. The direct illumination energy source that results from incident solar radiation was predicted by a solar load model using a solar ray-tracing algorithm. Two kinds of solid-particle receivers, each having a different exit condition for the solid particles, are modeled to evaluate the thermal performance of the receiver. Parametric studies, where the particle size and mass flow rate are varied, are made to determine the optimal operating conditions. The results also include detailed information for the gas velocity, temperature, particle solid volume fraction, particle outlet temperature, and cavity efficiency.

The Effect of the Microstructure of Semisolid Al Alloy on its Rheology

2014 ◽  
Vol 490-491 ◽  
pp. 109-112
Author(s):  
De Wen Cao ◽  
Jia Huan Wang ◽  
Yu Qing Sun ◽  
Ke Hua Chen ◽  
Cheng Ming Yu ◽  
...  
Keyword(s):  
Particle Size ◽  
Rheological Behavior ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Alloy System ◽  
The State ◽  
Solid Particles ◽  
Al Alloy ◽  
Agglomerate Size ◽  
The One

In the present work, the effect of the microstructure of AlSi6Mg2 alloy on its macro-rheological behavior of the steady AlSi6Mg2 alloy is investigated. Specifically, the effect of particle size, packing mode and degree of the agglomeration of particles are analyzed. It can be seen that the apparent viscosity decreases with increasing the particle size (d) ifdis between a few μm and 200 μm, while the solid particle size does not affect viscosity except this region. This theoretical prediction is in qualitatively agreement with the experimental data. The trend of the variation of the average agglomerate size with the particle size is the same as the one of viscosity. The packing mode of solid particles in agglomerate is closely related to the solid volume fraction and the characteristics of the alloy system. Subsequently, the state of agglomeration of solid particles which determines the rheology of semisolid AlSi6Mg2 alloy, while the external flow conditions (such as shear rate) influence the viscosity by changing the state of agglomeration. Consequently, the particle size, the packing mode and the average agglomerate size have different effect on the rheological behavior of SSMS.

scholarly journals Computational investigation of liquid-solid slurry flow through an expansion in a rectangular duct

2014 ◽  
Vol 62 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Gianandrea Vittorio Messa ◽  
Stefano Malavasi
Keyword(s):  
Volume Fraction ◽  
Particle Density ◽  
Fluid Model ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Rectangular Duct ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Two Fluid Model ◽  
Two Fluid

Abstract The flow of a mixture of liquid and solid particles at medium and high volume fraction through an expansion in a rectangular duct is considered. In order to improve the modelling of the phenomenon with respect to a previous investigation (Messa and Malavasi, 2013), use is made of a two-fluid model specifically derived for dense flows that we developed and implemented in the PHOENICS code via user-defined subroutines. Due to the lack of experimental data, the two-fluid model was validated in the horizontal pipe case, reporting good agreement with measurements from different authors for fully-suspended flows. A 3D system is simulated in order to account for the effect of side walls. A wider range of the parameters characterizing the mixture (particle size, particle density, and delivered solid volume fraction) is considered. A parametric analysis is performed to investigate the role played by the key physical mechanisms on the development of the two-phase flow for different compositions of the mixture. The main focuses are the distribution of the particles in the system and the pressure recovery

Localized Particle Concentration Measurement in Slurry Flows Using A-Scan Ultrasound Technique

2009 ◽  
Author(s):  
John M. Furlan ◽  
Venkat Mundla ◽  
Jaikrishnan Kadambi ◽  
Nathaniel Hoyt ◽  
Robert Visintainer ◽  
...  
Keyword(s):  
Solid Particle ◽  
Particle Concentration ◽  
Volume Fraction ◽  
Computational Study ◽  
Solid Particles ◽  
Acoustic Properties ◽  
Imaging Method ◽  
Concentration Profiles ◽  
Calibration Data ◽  
Slurry Flows

In the design of slurry transport equipment, the effects of solid particle concentration on hydraulic performance and wear have to be considered. This study involves examining the acoustic properties of slurry flows such as velocity, backscatter and attenuation as a function of volume fraction of solid particles. Ultrasound A-mode imaging method is developed to obtain particle concentration in a flow of soda lime glass particles (diameter of 200 micron) and water slurry in a 1″ diameter pipe. Based on the acoustic properties of the slurry a technique is developed to measure local solid particle concentrations. The technique is used to obtain concentration profiles in homogeneous (vertical flow) and non-homogeneous (horizontal flow) slurry flows with solid particle concentrations ranging from 1–10% by volume. The algorithm developed utilizes the power spectrum and attenuation measurements obtained from the homogeneous loop as calibration data in order to obtain concentration profiles in other (i.e. non-homogenous) flow regimes. A computational study using FLUENT was performed and a comparison is made with the experimental results. A reasonable agreement between the experimental and computational results is observed.

The Steady State Rheological Behavior of Semisolid AlSi6Mg2 Alloy

2011 ◽  
Vol 339 ◽  
pp. 257-260 ◽  
Author(s):  
Hong Chao Luo ◽  
Shi Pu Chen ◽  
Qin Nie ◽  
En Sheng Xu ◽  
Li Ping Ju
Keyword(s):  
Steady State ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Experimental Results ◽  
Present System ◽  
Flow Conditions ◽  
Good Agreement

In the present work, basing on the rheological model of Chen and Fan (CF) [1] of semisolid metal slurries (SSMS), the rheological behavior at steady state of AlSi6Mg2 alloy is investigated. Experimental results on steady state viscosity of the present system in the literature are used to determine the parameters of the CF model by fitting. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The theoretical prediction of the CF model is in good agreement with the experimental results in the literatures quantitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. Specifically, the external flow conditions such as shear rate influences the viscosity by changing the agglomeration degree of the solid particles, that is, the effective solid volume fraction and then changing the viscosity.

Thermal Dissociation of CH4 Using a Particle-Flow Chemical Reactor Exposed to Concentrated Solar Radiation

2008 ◽  
Author(s):  
Gilles Maag ◽  
Francisco Javier Gutierrez ◽  
Wojciech Lipinski ◽  
Aldo Steinfeld
Keyword(s):  
Solar Radiation ◽  
Volume Fraction ◽  
Solid Phase ◽  
Particle Volume Fraction ◽  
Thermal Dissociation ◽  
Chemical Reactor ◽  
Particle Flow ◽  
Carbonaceous Particles ◽  
Phase Volume Fraction ◽  
Concentrated Solar Radiation

The performance of a 5 kW particle-flow chemical reactor for the co-production of H2 and C by thermal decomposition of CH4 is investigated using concentrated solar radiation as the energy source of high-temperature process heat. The solar reactor features a directly-irradiated flow of CH4 laden with carbonaceous particles that serve the functions of radiant absorbers and nucleation sites for the heterogeneous cracking reaction. Main operational parameters are the solar power input, CH4 mass flow rate, and solid phase volume fraction. Their effect on the chemical conversion and solid products’ characteristics are examined for active carbon and carbon black laden particles. Higher particle volume fraction resulted in higher radiative absorption and enhanced kinetics.

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