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.

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.

Metal Temperature Prediction of a Dry Low NOx Class Flame Tube by Computational Fluid Dynamics Conjugate Heat Transfer Approach

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Antonio Andreini ◽  
Lorenzo Mazzei ◽  
Giovanni Riccio ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Operating Conditions ◽  
Metal Temperature ◽  
Thermal Loads ◽  
Flame Tube ◽  
Numerical Predictions ◽  
Partial Load ◽  
Critical Components

Combustor liner of present gas turbine engines is subjected to high thermal loads as it surrounds high temperature combustion reactants and is hence facing the related radiative load. This generally produces high thermal stress levels on the liner, strongly limiting its life expectations and making it one of the most critical components of the entire engine. The reliable prediction of such thermal loads is hence a crucial aspect to increase the flame tube life span and to ensure safe operations. The present study aims at investigating the aerothermal behavior of a GE Dry Low NOx (DLN1) class flame tube and in particular at evaluating working metal temperatures of the liner in relation to the flow and heat transfer state inside and outside the combustion chamber. Three different operating conditions have been accounted for (i.e., lean–lean partial load, premixed full load, and primary load) to determine the amount of heat transfer from the gas to the liner by means of computational fluid dynamics (CFD). The numerical predictions have been compared to experimental measurements of metal temperature showing a good agreement between CFD and experiments.

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.

scholarly journals Three-dimensional Analysis of Air Flow in a Flat Plate Solar Collector

2018 ◽  
Author(s):  
Mohammed Amine Amraoui ◽  
Khaled Aliane
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flat Plate ◽  
Solar Collector ◽  
Three Dimensional ◽  
Outlet Temperature ◽  
Computational Fluid Dynamics Cfd ◽  
Flat Plate Collector ◽  
Work Done

This paper presents the study of fluid flow and heat transfer in solar flat plate collector by using Computational Fluid Dynamics (CFD) which reduces time and cost. In the present paper the computational fluid dynamics (CFD) tool has been used to simulate the solar collector for better understanding the heat transfer capability. 3D model of the collector involving air inlet, the collector is modeled by ANSYS Workbench and the grid was created in ANSYS ICEM. The results were obtained by using ANSYS FLUENT and ANSYS CFX. The objective of this work is to compare theoretically and experimentally work done with the work done by using computational fluid dynamics (CFD) tool with respect to flow and temperature distribution inside the solar collector. The outlet temperature of air is compared with experimental results and there is a good agreement in between them.

scholarly journals Analysis of Liquid Cooling in Microchannels Using Computational Fluid Dynamics (CFD)

2021 ◽  
Author(s):  
Chitra Boobalan ◽  
Sudha Ganesh ◽  
Parthiban Rangaswamy
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Iron Oxide ◽  
Heat Sink ◽  
Solid Particles ◽  
Hybrid Nanofluid ◽  
Base Temperature ◽  
Liquid Cooling ◽  
Computational Fluid Dynamics Cfd

Liquid cooling is an extremely successful process to remove excess heat generated, with the usual procedure of heat transfer using coolant in desktop PCs. In this regard, heat transfer with minimal size equipment can be achieved by the addition of nanosized solid particles to the base fluid. The hybrid nanofluid is synthesized by dispersing the synthesized mono nanofluid in a volume fraction of 0.2 iron oxide with 0.8 fractions of graphene nanofluid to form a graphene/iron oxide combination. These nanoparticles increase the heat transfer coefficient as they have high thermal conductivity when compared to conventional heat transfer fluids like water or ethylene glycol. Stability is increased and sedimentation is reduced because of the large surface area of a nanoparticle. FLUENT, the most widely used computational fluid dynamics (CFD) software package, based on the finite volume method, and is used to run the thermal simulations for estimating the base temperature of the heat sink. The scope of this chapter is to find the base temperature of the heat sink using simulations. The experimentally measured base temperature is 310.01 K and in the simulation, it is 310.81 K for the flow rate of 0.75LPM. All the simulated surface temperatures are compared with experimentally determined temperatures for simulation validation.

Experimental and computational fluid dynamics modeling of a novel tray humidifier column in humidification dehumidification desalination; evaluation of hydrodynamic and heat transfer characteristics

2020 ◽  
Vol 234 (3) ◽  
pp. 275-284
Author(s):  
Taleb Zarei ◽  
Reza Hamidi Jahromi ◽  
Arash Mohammadi Karachi
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Rectangular Cross Section ◽  
Seawater Temperature ◽  
Operating Conditions ◽  
Dynamics Modeling ◽  
Heat Transfer Characteristics ◽  
Computational Fluid Dynamics Modeling ◽  
Transfer Characteristics

In this article, a novel tray humidifier column for humidification dehumidification desalination was proposed. The performance of the humidifier column has been investigated with experimental and computational fluid dynamics simulations. The hydrodynamics and heat transfer characteristics of this tray humidifier has been studied. A stainless steel sieve tray with a rectangular cross section with a dimension of 20 × 50 cm was used in the experimental study. In computational fluid dynamics modeling, a transient three-dimensional model has been developed based on the volume of fluid framework by using standard k-epsilon model. The effect of air and seawater flow rate and inlet seawater temperature on the exit air temperature has been investigated. The results show that the humidifier effectiveness of the tray humidifier column varies between 0.67 and 0.87 depending on operating conditions. Then, tray column can be used in humidification dehumidification desalination systems with advantages such as compact equipment, low-pressure drop, and handling solids or other sources of fouling.

Granular Flow and Heat-Transfer Study in a Near-Blackbody Enclosed Particle Receiver

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Janna Martinek ◽  
Zhiwen Ma
Keyword(s):  
Heat Transfer ◽  
Granular Flow ◽  
High Efficiency ◽  
Flow Instability ◽  
Solid Particles ◽  
Particle Flow ◽  
Outlet Temperature ◽  
Conductive Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Concentrating solar power (CSP) is an effective means of converting solar energy into electricity with an energy storage capability for continuous, dispatchable, renewable power generation. However, challenges with current CSP systems include high initial capital cost and electricity price, and advances are needed to increase outlet temperature to drive high-efficiency power cycles while simultaneously maintaining stability of the heat-transfer medium and thermal performance of the receiver. Solid-particle-based CSP systems are one alternative projected to have significant cost and performance advantages over current nitrate-based molten salt systems. NREL is developing a design that uses gas/solid, two-phase flow as the heat-transfer fluid (HTF) and separated solid particles as the storage medium. A critical component in the system is a novel near-blackbody (NBB) enclosed particle receiver that uses an array of absorber tubes with a granular medium flowing downward through channels between tubes. Development of the NBB enclosed particle receiver necessitates detailed investigation of the dimensions of the receiver, particle-flow conditions, and heat-transfer coefficients. This study focuses on simulation and analysis of granular flow patterns and the resulting convective and conductive heat transfer to the particulate phase using Eulerian–Eulerian two-fluid modeling techniques. Heat-transfer coefficients in regions with good particle/wall contact are predicted to exceed 1000 W/m2 K. However, simulations predict particle/wall separation in vertical flow channels and a resultant reduction in heat transfer. Particle-flow visualization experiments confirm particle/wall separation, but also exhibit complex periodic behavior and flow instability that create intermittent side-wall contact and enhance heat transfer above that predicted by the theoretical simulations.

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.

Application of Computational Fluid Dynamics in the Simulation of a Radioactive Waste Vitrification Facility

2004 ◽  
Author(s):  
Chris Barringer ◽  
Jonathan Berkoe ◽  
Chris Rayner ◽  
Gene Huang
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Radioactive Waste ◽  
Waste Treatment ◽  
Ventilation System ◽  
Heat Removal ◽  
Local Environment ◽  
Operating Conditions ◽  
Department Of Energy

The Columbia River in Washington State is at risk of radioactive contamination — a legacy of the cold war. Two hundred thousand cubic meters (fifty-three million US gallons) of radioactive waste is stored in 177 underground tanks at the Hanford site. This waste, which is 60% of the nation’s radioactive waste, is a product of 50 years of plutonium production for national defense. Bechtel National, Inc. has been commissioned by the U.S. Department of Energy to design and build a vast complex of waste treatment facilities to convert this waste into stable glass using a proven vitrification process. In this vitrification process, radioactive waste is mixed with glass-forming materials, then melted at approximately 1200C, and then poured into stainless steel canisters. These canisters are then permanently stored at secure aboveground or belowground facilities. The vitrification process results in a large amount of heat being stored in the hot glass. This heat must be removed within production schedule constraints. In the vitrification facility this glass is cooled in a small room called the Pour Cave. The room contains insulation to protect the concrete, and ventilation and water-cooled cooling panels to facilitate heat removal. The canister heat release rate depends on the thermal properties of the glass (which varies as the glass recipe changes), and the local environment, which includes other hot glass canisters. The cooling process is extremely complex. It is strongly coupled, and is driven by radiation, forced convection, natural convection and conduction heat transfer. Computational fluid dynamics, CFD, was used to predict the heat load to the ventilation system, the cooling panels and to the insulated concrete walls for a variety of operating conditions, providing the data needed for the design of these systems. Of particular interest was the temperature of the concrete, and whether or not design limits would be exceeded. The paper describes the special techniques that were developed to simulate the Pour Cave. This includes description of the modeling of the pouring of the glass, buoyancy modeling, and initialization of the simulation. Results are presented which show the predicted heat transfer characteristics throughout the Pour Cave.

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