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chimney guys. flow rate, average heat transfer coefficient, and total heat transfer rate. andrew enke steve jensen. background. residential chimneys have problems of smoke flow returning into the home 1/8 rule: minimum cross-sectional area ratio of the chimney flue and fireplace opening
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chimney guys flow rate, average heat transfer coefficient, and total heat transfer rate andrew enke steve jensen
background • residential chimneys have problems of smoke flow returning into the home • 1/8 rule: minimum cross-sectional area ratio of the chimney flue and fireplace opening • chimney efficiency decreases if chimney height is too short or too tall
grandma’s chimney H = 8.2 m D = .152 m A = .0182 m2 Tm,i = 17.8 °C Tm,0 = 208 °C u = 1.6 m/s procedure steve’s chimney H = 3.7 m D = .203 m A = .0324 m2 Tm,i = 23 °C Tm,0 = 223 °C u = 2.3 m/s
grandma’s chimney hbar(W/m2-K) = 1.6885 q (W) = 5088.3287 q" (W/m2) = 11.0705 Q (m3/s) measured = 0.0301 Q (m3/s) predicted = 0.0292 conclusion steve’s chimney • hbar(W/m2-K) = 2.4355 • q (W) = 1368.7902 • q" (W/m2) = 586.2287 • Q (m3/s) measured = 0.0437 • Q (m3/s) predicted = 0.0746