chemkin 介绍 - 北京大学工学院 · 2014-01-22 · 《燃烧学基础》第四章 chemkin...

《燃烧学基础》第四章 CHEMKIN 北京大学工学院

CHEMKIN 介绍

陈正

北京大学工学院力学与空天技术系

《燃烧学基础》第四章 CHEMKIN 北京大学工学院 2

Homogeneous Ignition Process

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1

Time (s)

Mo

lefr

act

ion

Te

mp

era

ture

(K)

0 0.025 0.05 0.07510-9

10-7

10-5

10-3

10-1

1000

1500

2000

2500

T

O

H

OH

CH3

HO2

CH4T

Homogeneous IgnitionCH4/air (Phi=1)

P=1atm,T0=1200K


Homogeneous Ignition Process

Time (s)

XC

H3,

d[C

H3

]/d

t(m

ole

/cm

3s)

Co

ntr

ibu

ctio

nto

d[C

H3]/

dt

10-5 10-4 10-3 10-2 10-1

10-10

10-8

10-6

10-4

10-2

-0.2

0

0.2

0.4

0.6

0.8

d[CH3]/dtXCH3

R156R158 R119

R155

R98R118

R53R11

R11: CH4+O = CH3+OHR53: CH4+H = CH3+H2R98: CH4+OH= CH3+H2OR118: CH4+O2 = CH3+HO2R119: CH3+HO2 = CH3O+OHR155: CH3+O2 = CH2O+OHR156: CH3+O2 = CH3O+OR158: 2CH3(+M) = C2H6(+M)

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1


Reaction Design: CHEMKIN

CHEMKIN: cklib.f

http://www.reactiondesign.com


CHEMKIN Software



kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1

T0, P, Yk,0

T(t), Yk(t)

cklib.f


Gas phase kinetics subroutine library

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1

cklib.f


Input: reaction mechanism


Three-body reactions


Pressure-dependent reactions


Net production rate: creation rate-destruction rate

I 反应数目K 组分数目

—— 第k个组分的静生成率 [mole/m3s]

生成率：

消耗率：


CKWYP in cklib.f


Other subroutines

Pressure (EOS) Mean molecular weight


Thermal dynamic properties

P

kkknk

C

Wh

dt

dT

)(1

NASA Polynomial format


Themal dynamic data input


Other thermal dynamic properties


Quick Reference Guide to cklib.f


Sample problem——homogeneous ignition

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1

Time (s)

Mo

lefr

act

ion

Te

mp

era

ture

(K)

10-4 10-3 10-2 10-110-9

10-7

10-5

10-3

10-1

1000

1500

2000

2500

T

OH

OH

CH3

HO2

CH4

Homogeneous IgnitionCH4/air (Phi=1)

P=1atm,T0=1200K


cklib.f: Gas phase kinetics subroutine library

INITCK.F : to initialize chemkin database

MAIN_IGNIT0D.F: homogeneous ignition problem

REACTION1.F: to update T and Yi (stiff ODE solver)

REACTION2.F: to update T and Yi (Explicit Euler)

tranlib.f: transport properties subroutine library

VODEJU.F: stiff ODE solver


Homogeneous Ignition


Homogeneous Ignition


VODE solver, implicit scheme for stiff ODEs


ODE integration: explicit Euler scheme


ODE integration: explicit Euler scheme

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1


Practice

1,For H2/air (equivalence ratio 1.0, constant pressure

P=1atm), plot the ignition delay time (defined as

the time when maximum dT/dt occurs) as a

function of 1000/T0 (T0=1000, 1100, …1600K).

2,For H2/air (equivalence ratio 1.0, constant volume

with P0=1atm), plot the ignition delay time

(defined as the time when maximum dT/dt occurs)

as a function of 1000/T0 (T0=1000, 1100, …1600K).

Compare results from problem 1 and problem 2.


Practice

3,For H2/air (equivalence ratio 1.0, constant volume with P0=1atm, T0=1400K):

kkk W

dt

dY

P

kkknk

C

Wh

dt

dT

)(1

Method I:

Method II:

kkk W

dt

dY

T

T kPkk

NS

kkk dTTChThwithhThYTh

0

)()()()( ,,00

1

)(/])([ 0 oldP

oldoldnew TChThTT

The temperature is updated via Newton iteration:


NOTE

Many slides are copied from materials in the following document:

This file should be used in the class only !

chemkin 介绍 - 北京大学工学院 · 2014-01-22 · 《燃烧学基础》第四章 chemkin...

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