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Further Cooling of Furnace Gases. P M V Subbarao Professor Mechanical Engineering Department. Change the Modes of Heat Transfer for Better use…. Measures of Furnace Performance. Temperature Field Coefficient.
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Further Cooling of Furnace Gases P M V Subbarao Professor Mechanical Engineering Department Change the Modes of Heat Transfer for Better use….
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 ris 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
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.
Measurement of Local Heat Flux Distribution & Control System
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.
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
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.
Evaluation • Submission of report : 20th April 2011. • Presentations: 23rd April 2011 (Saturday : 10.00 am onwards). • 30 to 40% weightage.
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