The Greenhouse effect A T M P G R E E N H OU S E 2 and is con tion back (G 13 How do heat-trapping gases work? o0agragaac0s2h8 osphenc gases 0000 ☐Carbon dioxide 100 surface warms from the energy back to the atmosphere as infrared h8a8n9yaaS space.When gre se gases aharection,incuihg6adk concentrationofa he nhous Wavelength (um) Earth. 名9新s院a 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn)14
澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT 澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT How do heat-trapping gases work? The energy from the sun that reaches Earth's surface is mostly "shortwave" radiation - mostly visible light. This energy passes freely through the atmosphere and is absorbed by Earth’s surface. The surface warms from the energy input, and some of its heat projects back to the atmosphere as infrared radiation. The greenhouse gases in the atmosphere absorb 95% of the energy in infrared radiation, allowing only 5% to pass into space. When greenhouse gases absorb energy, heat is released in all directions, including back towards Earth. As the concentration of greenhouse gases increases, this “insulating blanket” thickens, further warming the Earth.
The Top Five Climate-Changing Gases n dioxide (CO) -level ozone(O Heat-Trapping Ga Carbon dioxide(CO Methane (CH,) Low-level ozone (O. Halogenated carbor Halogenated carbons Methane (CH) Nitrous oxide (NO Nitrous oxide(NO 《燃烧学基础》1， 5 能源转换→大气污染 ~1亿吨污染物排放年 C02 UHC SOx Particulates 0 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn)16
澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT The Top Five Climate-Changing Gases 澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT 㜳Ⓠ䖢ᦘ ė ཝ≊⊗ḉ CO2 SOx NOx UHC Particulates ~1ӯ⊑ḃ⢙ᧂ᭮/ᒤ SOx NOx
大气污染 Big concern...thick pollution hides building in Beijing 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn)17 能源转换 一辆总重为1吨的汽车以100公里/小时的速度行驶，其 动能相当于燃烧多少汽油释放的能量？ A,一勺 B,一杯 一瓶 汽车动能E=0.5x1000x(100/3.6)2≈0.4x106J 汽油(CgH1g)燃烧放热量： CgH1g+12.5(02+3.76N2)→8C02+9H20+47N2(+48x106J/kgfue1.) 二两米饭vs.二两白酒？ 《燃烧学基础》1，绪论 陈(cz@pku.edu.cn18
澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT ཝ≊⊗ḉ Big concern … thick pollution hides building in Beijing 澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT 18 㜳Ⓠ䖢ᦘ ж䖼ᙱ䠃Ѱ ⎭ᒩ䶘рॽ ਫ਼Ⲻ⊳䖜ԛޢ䠂ቅᰬⲺ䙕ᓜ㺂催θެ ࣞ㜳ᖉӄ⟹✝ཐቇ⊳⋯䠀᭴Ⲻ㜳䠅ϋ $θжर %θжᶥ &θж⬬ ⊳䖜ࣞ㜳 (N [[ Ŋ [ - ⊳⋯ &+ ⟹✝᭴✣䠅φ &+ 21 ė&2 +21 [ -NJIXHO ӂњ㊩侣 YVӂњⲳ䞈 " [
能源利用效率：汽车 85%,35%,10%,1%? 2.6% 4.2% 《燃烧学基础》1，绪论 陈证(cz@pku.edu.cn)19 内燃机热效率提高 Where does the energy go? Transionofthemalefcencycdgasolneengne Thermal effici oduced engine:max.-40% 2000 2010 02 Gross thermal efficiency ~37.6% (0ida2017刀 Ideal Carnot efficiency ~1-300/1800=83% Otto cycle efficiency:68%(compression ratio of 17) 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn20
澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT 㜳Ⓠ⦽᭾⭞φ⊳䖜 20.4ˁ 85%, 35%, 10%, 1% ? 0.4ˁ 澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT ⟹ᵰ✣᭾⦽ᨆ儎 20 Gross thermal efficiency ~ 37.6% Ideal Carnot efficiency ~ 1-300/1800=83% Otto cycle efficiency: 68% (compression ratio of 17) (lida 2017)
内燃机热效率提高 Where does the energy go? University of Wisconsin RCCI low temperature combustion engine Gross thermal efficiency ~37.6% Gross thermal efficiency:59.7 %/o (Reitz et al.2012) .Ideal Carnot efficiency ~1-300/1800=83% .Otto cycle efficiency:68%(compression ratio of 17) 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn21 Low temperature combustion Newton's cooling equation >Super-Lean burn q(0)=A-h()(Tgas(0)-Tsurface(0)] Reduction o Super-Lean erating High turbulent flow (=20~50 m/s,u'=5 m/s) High EGR (EGR rate =20 % (ida2017) 《燃烧学基础》1，绪论 陈正(cz@pku.edu.cn)22
澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT ⟹ᵰ✣᭾⦽ᨆ儎 21 Gross thermal efficiency ~ 37.6% Ideal Carnot efficiency ~ 1-300/1800=83% Otto cycle efficiency: 68% (compression ratio of 17) Gross thermal efficiency˖ 59.7 % University of Wisconsin RCCI low temperature combustion engine (Reitz et al. 2012) 澦䏝ׁक澧ͬ ঠ ୟࠔ I`&VQ[KJ[IT Low temperature combustion (lida 2017)