Modeling of bed-to-wall heat transfer coefficient in a large-scale CFBC by fuzzy logic approach

2016 ◽  
Vol 94 ◽  
pp. 327-334 ◽  
Author(s):  
Jaroslaw Krzywanski ◽  
Wojciech Nowak
Keyword(s):  
Heat Transfer ◽  
Fuzzy Logic ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Large Scale ◽  
Wall Heat Transfer ◽  
Fuzzy Logic Approach ◽  
Logic Approach

Fuzzy logic and bed-to-wall heat transfer in a large-scale CFBC

2018 ◽  
Vol 28 (1) ◽  
pp. 254-266 ◽  
Author(s):  
Jaroslaw Krzywanski ◽  
Marta Wesolowska ◽  
Artur Blaszczuk ◽  
Anna Majchrzak ◽  
Maciej Komorowski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fuzzy Logic ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Large Scale ◽  
Weighted Average ◽  
Local Heat Transfer ◽  
Wall Heat Transfer ◽  
Transfer Coefficients ◽  
Content Type

Purpose The purpose of this paper is to first present the key features of the fuzzy logic (FL) approach as a cost-effective technique in simulations of complex systems and then demonstrate the formulation and application of the method. Design/methodology/approach The FL approach is used as an alternative method of data handling, considering the complexity of analytical and numerical procedures and high costs of empirical experiments. The distance from gas distributor, the temperature and the voidage of the bed, flue gas velocity and the load of the boiler are the input parameters, whereas the overall heat transfer coefficient for the membrane walls constitutes the output. Five overlapping sigmoid and constant linguistic terms are used to describe the input and the output data, respectively. The Takagi–Sugeno inference engine and the weighted average defuzzification methods are applied to determine the fuzzy and crisp output value, respectively. Findings The performed FL model allows predicting the bed-to-wall heat transfer coefficient in a large-scale 670 t/h circulating fluidized bed (CFB) boiler. The local heat transfer coefficients evaluated using the developed model are in very good agreement with the data obtained in complementary investigations. Originality/value The performed model constitutes an easy-to-use and functional tool. The new approach can be helpful for further research on the bed-to-wall heat transfer coefficient in the CFB units.

scholarly journals The Non-Iterative Estimation of Bed-to-Wall Heat Transfer Coefficient in a CFBC by Fuzzy Logic Methods

2016 ◽  
Vol 157 ◽  
pp. 66-71 ◽  
Author(s):  
J. Krzywanski ◽  
M. Wesolowska ◽  
A. Blaszczuk ◽  
A. Majchrzak ◽  
M. Komorowski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fuzzy Logic ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Heat Transfer ◽  
Iterative Estimation

The Use of High Blockage Ribs to Enhance Heat Transfer Coefficient Distributions in a Model of an Integrally Cast Cooling Manifold

2006 ◽  
Author(s):  
Ioannis Ieronymidis ◽  
David R. H. Gillespie ◽  
Peter T. Ireland ◽  
Robert Kingston
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Turbine Blade ◽  
Large Scale ◽  
Thermal Contact ◽  
Maximum Level ◽  
Blade Cooling ◽  
Cooling Passage ◽  
The Heat Transfer Coefficient

In this paper detailed experimental measurements and computational predictions of heat transfer coefficient distributions in a large scale perspex model of a novel integrally cast blade cooling geometry are reported. In a gas turbine blade, the cooling passage investigated is integrally cast into the blade wall, providing good thermal contact with the outer surface of the turbine blade. Flow enters the racetrack passage through the root of the blade and exits to a central plenum through a series of nineteen transfer holes equally spaced in a staggered arrangement across the span of the blade. The Reynolds number changes continuously along the passage length because of the continuous ejection of fluid through a series of 19 transfer holes to the plenum. The smooth passage surface opposite is in closest proximity to the external surface, and this investigation has characterised the heat transfer coefficient on this surface at a range of engine representative inlet Reynolds numbers using a hybrid transient liquid crystal technique. The ability of three different rib configurations to enhance the heat transfer on this surface was also determined. Because the passage at engine scale is necessarily small, the rib height in all cases was 32.5% of the passage height. As the entire passage wetted surface is able to contribute to the blade cooling, and knowledge of the heat transfer coefficient distribution on the holed surfaces is crucial to prediction of blade life, a commercial CFD package, Fluent, was used to predict the heat transfer coefficient distributions on the holed surface, where there was no optical access during these tests. This also allowed investigation of additional rib configurations, and comparison of the pressure penalty associated with each design. The study showed that the turbulator configuration used allows the position and maximum level of heat transfer coefficient enhancement to be chosen by the engine designer. For the configurations tested heat transfer coefficient enhancement of up to 32% and 51% could be achieved on the holed surface and the ribbed surface respectively. For minimum additional pressure drop 45° ribs should be used.

Heat transfer properties of metal foam supports for structured catalysts: Wall heat transfer coefficient

2013 ◽  
Vol 216 ◽  
pp. 121-134 ◽  
Author(s):  
Enrico Bianchi ◽  
Tobias Heidig ◽  
Carlo Giorgio Visconti ◽  
Gianpiero Groppi ◽  
Hannsjörg Freund ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Metal Foam ◽  
Wall Heat Transfer ◽  
Structured Catalysts ◽  
Transfer Properties

scholarly journals Heat Transfer Performance in a Superheater of an Industrial CFBC Using Fuzzy Logic-Based Methods

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 919 ◽  
Author(s):  
Krzywanski
Keyword(s):  
Heat Transfer ◽  
Fuzzy Logic ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Practical Significance ◽  
Overall Heat Transfer Coefficient ◽  
Bed Temperature ◽  
The Heat Transfer Coefficient

The heat transfer coefficient in the combustion chamber of industrial circulating flidized bed (CFB) boilers depends on many parameters as it is a result of multifactorial mechanisms proceeding in the furnace. Therefore, the development of an effective modeling tool, which allows for predicting the heat transfer coefficient is interesting as well as a timely subject, of high practical significance. The present paper deals with an innovative application of fuzzy logic-based (FL) method for the prediction of a heat transfer coefficient for superheaters of fluidized-bed boilers, especially circulating fluidized-bed combustors (CFBC). The approach deals with the modeling of heat transfer for the Omega Superheater, incorporated into the reaction chamber of an industrial 670 t/h CFBC. The height above the grid, bed temperature and voidage and temperature, gas velocity, and the boiler’s load constitute inputs. The developed Fuzzy Logic Heat (FLHeat) model predicts the local overall heat transfer coefficient of the Omega Superheater. The model is in good agreement with the measured data. The highest overall heat transfer coefficient is equal 220 W/(m2K) and can be achieved by the SH I superheater for the following inputs l = 20 m, tb = 900 °C, v = 0.95, u = 7 m/s, M-C-R = 100%. The proposed technique is an effective strategy and an option for other procedures of heat transfer coefficient evaluation.

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