Advanced heat transfer ppt

boiling heat transfer ppt and basics of heat transfer ppt and heat transfer conduction convection radiation ppt
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Part 4: Heat transfer, NOx and Soot Emissions Reciprocating Internal Combustion Engines Prof. Rolf D. Reitz Engine Research Center University of Wisconsin-Madison 2014 Princeton-CEFRC Summer School on Combustion Course Length: 15 hrs (Mon.- Fri., June 23 – 27, 2014) Copyright ©2014 by Rolf D. Reitz. This material is not to be sold, reproduced or distributed without prior written permission of the owner, Rolf D. Reitz. 1 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Short course outine: Engine fundamentals and performance metrics, computer modeling supported by in-depth understanding of fundamental engine processes and detailed experiments in engine design optimization. Day 1 (Engine fundamentals) Part 1: IC Engine Review, 0, 1 and 3-D modeling Part 2: Turbochargers, Engine Performance Metrics Day 2 (Combustion Modeling) Part 3: Chemical Kinetics, HCCI & SI Combustion Part 4: Heat transfer, NOx and Soot Emissions Day 3 (Spray Modeling) Part 5: Atomization, Drop Breakup/Coalescence Part 6: Drop Drag/Wall Impinge/Vaporization/Sprays Day 4 (Engine Optimization) Part 7: Diesel combustion and SI knock modeling Part 8: Optimization and Low Temperature Combustion Day 5 (Applications and the Future) Part 9: Fuels, After-treatment and Controls Part 10: Vehicle Applications, Future of IC Engines 2 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Challen, 1998 Engine heat transfer Up to 30% of the fuel energy is lost to wall heat transfer Can influence engine ignition/knock Engine durability – catastrophic engine failure Scorching Detonation Cracking 3 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Han, 1995 Wang, 2012 Heat transfer Gas phase energy equation I  c s r uI p u J Q Q Q  t q Radiation source term w   u Dy r y Dyu / Qrr I,4Ω dΩ Ir   b  Ω4 wall Wall heat flux (account for compressibility) With radiation Without radiation   C u T ln T T 2.1y 33.34 G uC u T ln T T  g p g g w p g g w q q w w   2.1ln y 2.5 2.1ln y 2.5   T  g 2.1uT ln g  dT q 2.1  T w dT w   2.1G    dy  C y   gp dy yy 2.1ln 2.5   r G radiative heat flux = q w 4 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Wiedenhoefer, 2003 Radiation modeling Radiation Transfer Equation:  s Ω Ir,Ω a Ir,Ω Ir Sr,Ω  net s b 4 a net absorption coefficient, scattering coefficient net s   a extinction coefficient net s 4 T w Back body radiative flux (independent of angle) I r  b   Scattering terms, , S usually neglected compared to absorption s Radiation intensity at wall r 4  G q nΩ Ir,Ω dΩT  ww   nΩ0 surface emissivity  Discrete ordinates model nDir  r m m Q r I r 4 I r   b   m1 5 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Wiedenhoefer, 2003a Soot and gas absorption 1 a T, P, L ln 1 T, P, L Total absorption coefficient  g e g e  L e a  a a 1 1 1 1 1 net soot COH O   22 fuel CO CO H O 22 Soot absorption -1 CO absorption bands a1260C T m 2 soot soot Wide band model for CO and H O 2 2 3  2C 1  ,T  b band center  CT 2 e1  band center Importance of soot: 1 a aT gas soot T  r 4 35  Qrr a I,4Ω dΩ Ir a a T   TT  b gas soot   gas soot  Ω4 6 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Wiedenhoefer, 2000 Wall heat transfer Conjugate heat transfer modeling ERC - Heat Conduction in Components code (HCC) Iterative coupling between HCC and CFD code Unstructured HCC Mesh 7 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Wiedenhoefer, 2000 Wall heat transfer Cummins N14 engine . . . . . . . . . Caterpillar SCOTE engine Cut Plane 8 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Wiedenhoefer, 2003 Predicted piston temperature - CDC No Radiation Run 1 740 F = 0.7 Effect of radiation on wall heat loss Run 2 Run 3 720 Total heat loss increased by 30% due to With Radiation 700 Run 1 radiation. Run 2 680 Run 3 34% - head, 19% - liner, 47% - piston. 660 Lowers bulk gas temperatures 640 Results in lower NOx and higher soot 620 NOx reduced by as much as 30% (ave) 600 16 F = 0.5 580 Uniform Temp / No rad 14 Non-uniform Temp / With Rad 560 F = 0.7 -20 -15 -10 -5 0 12 Uniform Temp / No rad Start of Injection, ATDC Non-uniform Temp / With Rad 10 8 6 4 2 -20 -15 -10 -5 0 Start-of-injection, ATDC 9 CEFRC2-4, 2014 Peak Piston Temperature K NOx g/kWhPart 4: Heat transfer, NOx and Soot Emissions Gingrich, 2014 Wall heat flux measurements Dry Compressed Chilled Air Water Engine Geometry AVL 415S Smoke Base Engine GM 1.9L Diesel Choked Flow Meter Compression Ratio 16.3 Orifices Water Heater Displacement (Liters) 0.477 Horiba Stroke (mm) 90.4 Hydrocarbon Bore (mm) 82 Analyzer EGR Heat Exchanger Intake Valve Closing -132° aTDC Exhaust Valve Opening 112° aTDC Horiba Analyzers Swirl Ratio 1.5 -4.8 NOx Stock (Re- DC Dyno Air CO Piston Bowl Type entrant) Heater O2 Port Fuel Injectors Exhaust CO2 Intake CO2 Included Spray Angle 20° Port Swirl Barrel 4 Fuel Injection Pressure (bar) 2 to 10 Direct Control Heater Injectors Injector Rated Flow (cc/sec) 10 Valves 3 Intake Bosch Common Rail Injector Exhaust Surge 2 Surge Tank Number of Holes 7 Tank 1 Hole Diameter (mm) 0.14 Included Spray Angle 155° 4-cylinder engine head Injection Pressure (bar) 250 to 1000 bar cylinder 1,3,4 deactivated 10 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Gingrich, 2014 Thermocouples 5 7 1 Power 6 Piston Converter 4 Transmitter 2 Primary Coil 3 (Engine Mounted) Data Inductive Secondary Acqusition Power Coil Supply (Piston Mounted) Receiver • Fourier analysis is applied to find dynamic heat flux • Integral of the dynamic heat flux over the full cycle is zero T(t) T A cos(n t) B sin(n t) m n n Dynamic Steady N kn q (TT ) k (A B )cos(n t) (A B )sin(n t) m l n n n n l 2 n1 11 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Gingrich, 2014 Combustion strategy effects - CDC / HCCI / RCCI Mode 1 Mode 2 Mode 3 Mode 4 Speed (RPM) 1490 1900 2300 2300 IMEPg (bar) 4.2 5.7 5.7 8 CA50 (degATDC) 4 5 4.5 8 Swirl 1.5 1.5 1.5 1.5 Intake Temperature (C) 75 50 50 35 Intake Pressure (kPa) 115 130 130 188 ERG (%) 0 0 0 55 Regime Fuel Fuels: HCCI 91PON Gasoline / n-heptane RCCI F76 / 91PON Gasoline CDC F76 12 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Gingrich, 2014 Heat Release Rate 150 Combustion strategy effects Heat release rate Location 3 Temperature Mode 3 100 150 5.7 bar IMEPg CDC 5 deg ATDC CA50 HCCI 145 50 2300 rev/min RCCI 140 0 135 -20 -10 0 10 20 30 40 Crank Angle deg 6 Location 3 6 Location 7 x 10 130 x 10 5 5 T =169.1C T =191.8C m m T =155.4C 125 4 T =182.1C 4 m m T =140.6C T =158.5C m m 3 3 120 -400 -200 0 200 400 Crank Angle deg 2 2 1 1 0 0 -20 -10 0 10 20 30 40 -20 -10 0 10 20 30 40 Crank Angle deg Crank Angle deg 13 CEFRC2-4, 2014 2 Heat Flux W/m Temperature C 2 Heat Flux W/m AHRR J/degLocation 7 Location 7 6000 6000 Part 4: Heat transfer, NOx and Soot Emissions Gingrich, 2014 5000 5000 Combustion strategy effects - CDC / HCCI / RCCI Location 3 Location 7 4000 4000 6000 6000 CDC CDC 3000 3000 HCCI HCCI 5000 5000 RCCI RCCI 2000 2000 4000 4000 CDC CDC 1000 1000 3000 3000 HCCI HCCI RCCI RCCI 0 0 1 2 3 4 1 2 3 4 2000 2000 Mode Mode 1000 1000 0 0 1 2 3 4 1 2 3 4 Mode Mode Heat losses significantly less with low temperature combustion strategies 14 CEFRC2-4, 2014 2 Integrated Heat Flux J/m 2 Integrated Heat Flux J/m 2 Integrated Heat Flux J/m 2 Integrated Heat Flux J/m Part 4: Heat transfer, NOx and Soot Emissions Hendricks, 2014 Heavy-duty diesel heat flux data Compare CDC and RCCI combustion at matched CDC CA50, load, Φg (4.6°CA ATDC, 0.35) RCCI piston heat flux measured to be lower than CDC Area integrated HX and temp. determined RCCI CDC RCCI 7.7 5.9 ∫Piston HX fuel energy (%) GTE (%) 51.2 52.7 15 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Engine emissions - transportation & toxic air pollutants Criteria air contaminants (CAC), or criteria pollutants - air pollutants that cause smog, acid rain and other health hazards. EPA sets standards on: 1.) Ozone (O3), 2.) Particulate Matter (soot): PM10, coarse particles: 2.5 micrometers (μm) to 10 μm in size PM2.5, fine particles: 2.5 μm in size or less 3.) Carbon monoxide (CO), 4.) Sulfur dioxide (SO2), 5.) Nitrogen oxides (NOx), 6.) Lead (Pb) Toxic air pollutants - Hazardous Air Pollutants or HAPs known to cause or suspected of causing cancer or other serious health ailments. - Clean Air Act Amendments of 1990 lists 188 HAPs from transportation. In 2001, EPA issued Mobile Source Air Toxics Rule: - identified 21 MSAT compounds. - a subset of six identified having the greatest influence on health: benzene, 1,3-butadiene, formaldehyde, acrolein, acetaldehyde, and diesel particulate matter (DPM). Harmful effects on the central nervous system: BTEX/N/S - benzene, toluene, ethylbenzene, xylenes, Naphthalene, Styrene 16 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Curtis, 2014 Engine emissions - transportation & toxic air pollutants 17 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Diesel emission solutions – Selective Catalytic Reduction (SCR) and Diesel Particulate Filter (DPF) US EPA 2010 HD soot: 0.0134 g/kW-hr NOx: 0.2682 g/kW-hr. 1.) EGR? Navistar – no SCR Enabling technologies (Cost?): Improved combustion bowl design - PCCI Improved EGR valves, air-handling, VVA Twin-series turbochargers, inter-stage cooling High-pressure CR fuel injection (31,800 psi) 2.) SCR? Cummins Cu-Zeolite with DEF for 2010 Claim 3-5% fuel economy gain (Class 8 truck 1% ≈1,000 per year) “StableGuard Premix” dose rate 2% of fuel consumption rate Cost? 3/gal? AdBlue at pump in Germany 12/gal Volvo announced surcharge of 9,600 for 2010 compliance (complex – dosing rate, DEF freezes at 12F, gasifies at 130F) Plus 7,500 for 2007 compliance  AT system cost equals cost of engine 18 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Yoshikawa, 2008 NOx modeling Zeldo’vich thermal NOx mechanism Rate controlling step due to high N bond strength 2 ERC 12-step NOx model is based on GRI-Mech v3.11 and includes: Zeldovich, 1946 Thermal NOx Fenimore, 1979 Prompt NOx around 1000 K. Extensions Eberius, 1987 NO can convert HCN and NH 3 Guo, 2007 Interaction between NO and Soot 19 CEFRC2-4, 2014 Part 4: Heat transfer, NOx and Soot Emissions Kong, 2007 ERC 12 step NOx Mechanism SENKIN2 used to predict species histories. XSENKPLOT used to visualize reaction pathways and identify important reactions and species. Reduced mechanism validated for test temperatures from 700K to 1100 K and equivalence ratios from 0.3 to 3.0. Four additional species (N, NO, N O, NO ) 2 2 and 12 reactions added to ERC PRF mechanism Detailed mechanism: Smith, GRI-mech, 2005 20 CEFRC2-4, 2014