Experimental validation of CFD models for fluidized beds: Influence of particle stress models, gas phase compressibility and air inflow models

2006 ◽  
Vol 61 (5) ◽  
pp. 1705-1717 ◽  
Author(s):  
K. Johansson ◽  
B.G.M. van Wachem ◽  
A.E. Almstedt
Keyword(s):  
Gas Phase ◽  
Fluidized Beds ◽  
Experimental Validation ◽  
Cfd Models ◽  
Stress Models

Combustion of Biomass in Fluidized Beds: Problems and Some Solutions Based on Danish Experiences

2003 ◽  
Author(s):  
Weigang Lin ◽  
Anker D. Jensen ◽  
Jan E. Johnsson ◽  
Kim Dam-Johansen
Keyword(s):  
Gas Phase ◽  
Fluidized Beds ◽  
Early Stage ◽  
Full Scale ◽  
Boiler Load ◽  
High K ◽  
Fundamental Understanding ◽  
Annual Biomass ◽  
Operation Parameters ◽  
Boiler Design

This paper summarizes the major problems in firing and co-firing the annual biomass, such as straw, in both lab-scale and full-scale fluidized bed combustors. Two types of problems were studied: operational problems, such as agglomeration, deposition and corrosion; and emission problems, e.g. emissions of NO and SO2. Measurements of deposition and corrosion rate on the heat transfer surfaces, as well as gas phase alkali metal concentrations, were performed in full scale CFB boilers (an 80 MWth and a 20 MWth plant), which have been co-firing coal with straw and other biomass. Severe corrosion and deposition were observed in the superheater located in the loop-seal of the 80 MWth boiler. The boiler load variation has impact on the operation parameters. When the fraction of biomass with a high K-content (>1 wt. %) was higher than 60% on a thermal basis, the boiler suffered from severe agglomeration problems. Lab-scale experiments were carried out for the fundamental understanding of phenomena found in full-scale boilers and for testing possible solutions to the problems. The results showed a strong tendency of agglomeration in fluidized beds during combustion of straw, which normally have a high content of potassium and chlorine. The results indicate that the operational problems may be minimized by a combination of additives, improved boiler design, split of combustion air and detection of agglomeration at an early stage.

Innovative Design of a Robust Turbine Stage Using Flow Analysis and Subcomponent Rig Testing With Rapid Prototypes

2007 ◽  
Author(s):  
Jason Kielb ◽  
Kurt Weber ◽  
Bruce Crook
Keyword(s):  
Total Pressure ◽  
Experimental Validation ◽  
Flow Analysis ◽  
Ambient Air ◽  
Turbine Rotor ◽  
Small Subset ◽  
Test Case ◽  
Fourier Decomposition ◽  
Turbine Engine ◽  
Cfd Models

Designing turbine engine components for high cycle fatigue robustness can significantly reduce operating costs and improve safety. However, obtaining an optimum design and getting the new hardware into service using traditional methods is an expensive process. A process that combines state-of-the-art computational fluid dynamics (CFD) analytical simulations with subcomponent rig testing has been developed and demonstrated on a gas turbine engine. The analytical method involves spatial Fourier decomposition of vane exit total pressure from steady flow calculations. This provides an efficient method to reduce the design space and eliminate poor designs, resulting in a small subset of near-optimum designs. To confirm that the remaining candidate designs provide less unsteady forcing and to validate the CFD analysis, a unique experimental test rig was constructed. The experiments consisted of flowing ambient air through a subsection of the engine, while measuring the exit total pressure flow field around the turbine rotor exit annulus with a unique traversing probe. The measured exit total pressure was then Fourier decomposed in space to understand the resulting unsteady forcing on the blade. The costs of the flow rig and producing numerous sets of candidate hardware were much less expensive than full-scale engine or rotating rig tests. New hardware designs tested in the rig were manufactured using a rapid prototyping procedure, which allowed for extremely quick turn around in going from design concept to experimental validation. Good correlation between analysis and test was found, except in a few cases. The majority of these discrepancies were attributed to excitation sources that were impractical to include in the CFD models. This finding indicated that there are still circumstances for which the analytical tools were insufficient and hence experimental validation is still important. Both the analysis and experiments confirmed up to a 50% reduction in the amplitude of unsteady pressure for this particular engine test case.

Experimental validation of mechanical stress models by micro-Raman spectroscopy

1996 ◽  
Vol 36 (11-12) ◽  
pp. 1751-1754 ◽  
Author(s):  
I. De Wolf ◽  
G. Pozzat ◽  
K. Pinardi ◽  
D.J. Howard ◽  
M. Ignat ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Stress ◽  
Experimental Validation ◽  
Micro Raman Spectroscopy ◽  
Stress Models

Particle exchange in horizontal two-compartment fluidized beds – CFD simulation and experimental validation

2017 ◽  
Vol 28 (2) ◽  
pp. 543-552 ◽  
Author(s):  
Philipp Lau ◽  
Carsten-Rene Arlt ◽  
Matthias Potthoff ◽  
Matthias Kind
Keyword(s):  
Fluidized Beds ◽  
Experimental Validation ◽  
Cfd Simulation ◽  
Particle Exchange

scholarly journals Estimation and experimental validation of the circulation time in a 2D gas–solid fluidized beds

2013 ◽  
Vol 235 ◽  
pp. 669-676 ◽  
Author(s):  
S. Sánchez-Delgado ◽  
C. Marugán-Cruz ◽  
A. Soria-Verdugo ◽  
D. Santana
Keyword(s):  
Fluidized Beds ◽  
Experimental Validation ◽  
Circulation Time
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