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Further Cooling of Furnace Gases

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Presentation on theme: "Further Cooling of Furnace Gases"— Presentation transcript:

1 Further Cooling of Furnace Gases
P M V Subbarao Professor Mechanical Engineering Department Change the Modes of Heat Transfer for Better use….

2 Measures of Furnace Performance

3 Temperature Field Coefficient
Temperature field coefficient accounts for the temperature distribution in the furnace. It is a function of relative level of the burners and on the type of fuels burnt. The expression of M is given as: Z r is the relative position of highest temperature zone wrt to furnace bottom. DZ is a correction factor for tilt of burners. C1 &C2 are constants depend on fuel quality

4 Distribution of Heat Flux
Average Heat flux can be calculated using: As the temperature and emissivity of flame is not uniform in the furnace volume, the local heat flux is not uniform. Actual local wall temperature depends on the value of local heat flux. Special experiments are carried out to find the heat flux distribution on water wall.

5 Measurement of Local Heat Flux Distribution & Control System

6 Distribution of Heat Flux

7 Distribution of Heat Flux

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9 Calculation of Non-uniformity of Heat Flux
Experimental determination of zone wise value of non-uniformity index, hi . Calculate zone wise distribution of heat load. Develop a local resistance network to compute local wall temperature.

10 Elaborate Models for Better Analysis
Self-absorbing Models : Directional Averaging Methods 2-Flux, 4-Flux, Multiflux, DOM Differential Approximation Method Moment, Modified- Moment, PN – Appro Energy Methods Zone, MCM, Numerical (FD, FV) Hybrid Methods DTM, Ray Tracing ,Radiation Element

11 Format of Report At lease four references (journal/conference publications). Basic theory, Verification through standard problems, Special problems solved. Formulation of this method for Furnace cooling. All clues to model: Complex flame and furnace geometry. Complex properties of flame and gas. Boundary conditions.

12 Evaluation Submission of report : 20th April 2011.
Presentations: 23rd April 2011 (Saturday : am onwards). 30 to 40% weightage.

13 Have we completed furnace cooling ????

14 Thermal Structure of A SG
stack APH ESP ID Fan LTSH drum DPNL SH R H T screen tubes BCW pump Platen SHTR Economiser Furnace Bottom ash

15 Paths of Steam and Gas Drum Water walls Economizer

16 Furnace Energy Balance
Enthalpy to be lost by hot gases: Water walls Economizer Furnace

17 Other Radiative Exits of A Furnace

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