scholarly journals Extension of Weighted Sum of Gray Gas Data to Mathematical Simulation of Radiative Heat Transfer in a Boiler with Gas-Soot Media

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Samira Gharehkhani ◽  
Ali Nouri-Borujerdi ◽  
Salim Newaz Kazi ◽  
Hooman Yarmand
Keyword(s):  
Heat Transfer ◽  
Absorption Coefficient ◽  
Radiative Heat ◽  
Measured Data ◽  
Weighted Sum ◽  
Gas Temperature ◽  
Zone Method ◽  
Plant Site ◽  
Good Agreement ◽  
Steam Production

In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site.

Computation of Radiative Heat Transfer in a Cylindrical Enclosure

1996 ◽  
Author(s):  
Huiyu Fu ◽  
Ali Veshagh
Keyword(s):  
Heat Transfer ◽  
Absorption Coefficient ◽  
Combustion Chamber ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Gas Absorption ◽  
Combustion Model ◽  
Integration Scheme ◽  
Transfer Model ◽  
Zone Method

Abstract A radiative heat transfer model for cylindrical enclosure in which the gas and temperature are axi-symmetrically distributed was developed using the zone method of analysis. A rigorous numerical integration scheme was devised to calculate various types of direct exchange areas between different zones. The radiative heat transfer between gas zones and that between gas zones and surface zones could therefore be computed accurately based upon distributions of gas temperature and absorption coefficient. This radiation model was used to compute the radiative heat transfer in a diesel engine combustion chamber. Extensive soot data obtained via a sampling valve were used to calculate the gas absorption coefficient. An attempt was also made to allow for the radiation from the non-luminous gases, i.e. carbon dioxide and water vapour. Temperature distribution was obtained from a multi-zone combustion model. Results showed that the radiative heat transfer to the combustion chamber walls was negligible during the early stage of combustion, but represented a significant part of the total heat transfer when it reached its peak value. The results also showed the importance of radiative heat transfer between the various gas zones in the combustion chamber.

Validation of the Combustion Space Simulation of a Glass Furnace Model

2001 ◽  
Author(s):  
B. Golchert ◽  
S. L. Chang ◽  
M. Petrick ◽  
C. Q. Zhou
Keyword(s):  
Heat Transfer ◽  
Computer Simulations ◽  
Glass Furnace ◽  
Validation Studies ◽  
Radiative Heat ◽  
Operating Conditions ◽  
Department Of Energy ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Actual Operating

Abstract A completely coupled glass furnace simulation that combines calculations for the combustion space, glass melt, and radiative heat transfer throughout the furnace has been developed as part of a Department of Energy sponsored program. A major component of this program entailed the collection of an extensive set of data from an operating glass furnace for the purpose of validation. The data collected were compared with the results from computer simulations of the furnace based on the actual operating conditions. These comparisons indicated that the computated results were valid. This paper will present and discuss the gas velocity and gas temperature measurements/validation studies.

Computer Modeling of the Continuous Annealing Furnace

1992 ◽  
Vol 114 (4) ◽  
pp. 345-350 ◽  
Author(s):  
S. H. Jeong ◽  
M. Y. Ha
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Heat Transfer Analysis ◽  
Continuous Annealing ◽  
Transient Species ◽  
Annealing Furnace ◽  
Zone Method ◽  
Gas Radiation ◽  
Continuous Annealing Furnace

A computer program to calculate the strip temperature heated in the continuous annealing furnace was developed, using the zone method for radiative heat transfer analysis with the measured gas temperature in the furnace. Using the FE operator, the present study considered the effects of soot and transient species in addition to the H2O-CO2 gas mixture on the gas radiative heat transfer. The predicted strip temperature distribution for FE = 1.05 represented well the measured data. The maximum difference in the heat flux transfered to the strip from the combustion gas for FE = 1.0 (without soot and transient species gas radiation) and 1.05 (with soot and transient species gas radiation) was about 15 percent. The present study also investigated the effects of line speed and thickness variations on the strip temperature, establishing the bases for the on-line computer model.

Importance of Combined Lorentz-Doppler Broadening in High-Temperature Radiative Heat Transfer Applications

2004 ◽  
Vol 126 (5) ◽  
pp. 858-861 ◽  
Author(s):  
Anquan Wang ◽  
Michael F. Modest
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Critical Temperature ◽  
Absorption Coefficient ◽  
Radiative Heat Transfer ◽  
Total Pressure ◽  
Radiative Heat ◽  
Narrow Band ◽  
Spectral Lines ◽  
Doppler Broadening

The importance of combined Lorentz-Doppler (or Voigt) broadening of spectral lines in high-temperature radiative heat transfer applications is investigated. Employing narrow-band transmissivities as the criterion, the critical total pressure below which, and the critical temperature above which Doppler broadening has a significant effect on the absorption coefficient is established for gaseous H2O and CO2.

Computational Heat Transfer Analysis of a Furnace Using the WSGG Model

2000 ◽  
Author(s):  
Toshiaki Omori ◽  
Shunichi Yamaguchi ◽  
Toru Fusegi
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Present Model ◽  
Heat Transfer Analysis ◽  
Weighted Sum ◽  
Computationally Efficient ◽  
Reciprocity Laws ◽  
Dependent Absorption ◽  
Wsgg Model

Abstract Accurate radiative heat transfer analysis is challenging due to the strongly spectral-dependent absorption coefficient and the requirement for satisfying both the summation and reciprocity laws in thermodynamics. In the paper, nongray radiation is treated by way of a computationally efficient Weighted Sum of Gray Gases (WSGG) model without much sacrificing prediction accuracy. In the present model, three gray gas components are used, one of which simulates the radiative window. The thermodynamic laws are simultaneously treated using a Monte Carlo method subject to a symmetrization procedure. As a test problem, radiative heat transfer in an industrial model furnace is solved to demonstrate effects of gray/nongray radiation and the grid size for CFD and radiation calculations.

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