SOLUTIONS MANUAL FOR
Combustion Science
and
Engineering
by
Kalyan Annamalai
Ishwar K. Puri
** Immediate Download
** Swift Response
** All Chapters included
, Corrections in Problems, Tables and Charts
PROBLEM 6.7 Operating Pressure : 1000 kpa
PROBLMEM 7.6 CO: AIR MIXTURE
ASSUME T= 1800 K, P=1 BAR ; PLOT [CO] VS T; DO YOU BELIOEVE THE AB FOR BACKWARD
REACT RATE? WHAT IS THE PROBLEM?
Problem 7.7 already workd out; but detaile steps are given
Switch problems 7.8 and 7.9 ( i.e kinetics of problem 7.8 are in 7.9)
Problem 10-14 Solution:
Correct
⎧ ⎢1− ⎥ ⎫
⎡ a⎤
⎧ ⎢1− ⎥ ⎫
⎡ a⎤
⎨(1 + B) − (1 + B ) ⎣ r ⎦ ⎬ ⎨(1 + B) − (1 + B ) ⎣ r ⎦ ⎬
⎭ = 1 − 1 ⎧ 1 + B ⎡⎢⎣1− r ⎤⎥⎦ − 1⎫
a
φ = f* = ⎩ ⎭= ⎩
⎨( ) ⎬
B B B⎩ ⎭
Problem 10.29 RHO D= 2.5e-05
Prob 10-7: R, gas constant in kJ (kg K)
Text Example p 449-450; solution for part (b)
ml /ml0 = =0.80 0.20 = {1 – (3.3x10-6 m2/s t)/ (100x10-6)2 }3/2
t =0.42 = 2 ms !
For all Chapters, uless otherwise stated, ambient T = 25 C and ambient pressure = 100 kpa
Problem 10-14 solution:
Correct
⎧ ⎢1− ⎥ ⎫
⎡ a⎤
⎧ ⎢1− ⎥ ⎫
⎡ a⎤
⎨(1 + B) − (1 + B ) ⎣ r ⎦ ⎬ ⎨(1 + B) − (1 + B ) ⎣ r ⎦ ⎬
⎭ = 1 − 1 ⎧ 1 + B ⎡⎢⎣1− r ⎤⎥⎦ − 1⎫
a
φ = f* = ⎩ ⎭=⎩
⎨( ) ⎬
B B B⎩ ⎭
Problem 10.29 ; correct ρD =2.5e-05
3
,Problem 11.5 Modified
Problem 11.6 : Using .. solution of problem 11.4 5
Problem 11.14 : Use Single Film Model
11.14
Consider a flat carbon surface burning in air with air velocity at about 10 m/s. The air temperature
is 600 K. Assume properties of gas at surface temperature of carbon. Other data are as follows:
cpcarnon 4.39 kJ/kg K, ρcarbon = 1300 kg/m3, Tw = 611 K, hc,I 9203.2 kJ/kg , , hC,III =-14,360
kJ/kg X, Length of plate =0.1 m
Free Stream Gas data : YO2inf 0.23, YCO2inf 0.5, rest is N2 Tinf 600 K, Press
1 bar
Transport Propery data for air at 600 K λgas = 0.0000469 , Pr:=1, cpgas =1.051 kJ/kg K,
μ= 3.06x10-5 N s/m2, νw = 5.27E-05 m2/s ,
Obtain an integral solution for average burn rate. Use the profiles given in Example 5
USE Single film Model
Problem 12.10 and Prob 12.12 are duplicated
Problem 12.10.
Gaseous CH4 fuel is injected with a velocity of 5 cm/s into air. Assume ρD = 6.5x10-5 kg/m s.
HHV =50,000 kJ/kg Assuming incompressible flow, calculate:
a) The YF, YO2, YF and T vs y* profiles for a 2 cm wide slot jet at 50 cm from the wall. Plot the
profiles. Assume ρD = λ /cp for air at 1200 K.
b) The flame length for the jet in part a. (use properties at 300 K), let T ∞ = 300 , P ∞ = 101 kPa.
Problem 12.11.
The diameter of the burner is 0.373 cm. The flow rate of CH4 through the burner is 60 cm3/min.
The inlet temperature is 298 K and pressure is 104 kPa.. Assume ρD = 6.5x10-5 kg/m s
=constant.ν= 1.63E-04 m2/s; cp=1.175 kJ/kg ; . {LHV : 50000 kJ/kg}
a) The flame length for the jet in part a. (use properties at 300 K), let T ∞ = 300 , P ∞ = 100 kPa
b) The φ, YF, YO2, YF and T vs y* profiles at 5 cm from the wall. Plot the profiles.
Problem 12.12
Gaseous CH4 fuel is injected with a velocity of 5 cm/s into air. Assume ρD = 6.5x10-5 kg/m s.
HHV =50,000 kJ/kg Assuming incompressible flow, calculate:
a) The Φ/Φ0 (or = vx,/vx,max,), YF, YO2, YF and T vs y* profiles for a 2 cm wide slot jet at 50 cm
from the wall. Plot the profiles. Assume ρD = λ /cp for air at 1200 K.
b) The flame length for the jet (use properties at 300 K), let T ∞ = 300 , P ∞ = 101 kPa
4
, c) The flame length for the jet in part b is properties ta 300 K are used
( Note dy' = ρ/ρi dy or dy = dy' (ρi /ρ) = dy' (T/Ti); Knowing T or Φ profiles vs y' one can
integrate and obtain T vs y or use Euler's integration formulae in Q-spread sheet)
Problem 13.4
Determine the ignition temperature of cylindrical stream of coal particles of dia. 50 μm. We will
assume that coal particles burn heterogeneously.
coal , O 2 → x CO 2 , y H 2O
The coal composition is given as: ash 8.0%, carbon 76.3%, hydrogen 5.0%; oxygen 8.2% (dry).
Neglect N and S. Use Boie eq. for heating value. Assume Ahet = 450 m/s, E = 66, 000 kJ/kmole,
(a) Let radius of stream, R to be 5 mm. Determine T ∞ , I for A:F in the stream of 1:1, 2:1 and
4:1, (b) let R be 10 mm. Determine T ∞ , I for A:F of 1:1, 2:1 and 4:1; ρcoal = 1300 kg/m3, air
density 1.1 kg/m3. Assume that T∞,I =
Problem 13,5
Most explosive conditions are presumed to exist in the pulverizer mills at 0.5 g per liter [Power
Engineering, 1993].a) What is the probable ignition temperature for a cylindrical cloud of dia 20
cm? b)What is the temperature for 20 cm dia spherical cloud? Assume other dara similar to
Problem 13.4
Problem 13.7
*= hc*/[1+{ exp(1/θ)/ DIII,mod ] where θ is particle temperature of carbon and h*c =
If Qgen
(Sh/ Nu ) B ( R hc/[E Le cp]); DaIII,mod=[Ahet νO2 d/Sh Dw]. (seeText) . Ignoring change in
concentrations of fuel and oxidizer on Q gen
vs θ occurs such that
(a) show that maximum slope of Qgen
= exp(1/θ)/ DIII,mod
{1/θ} = 2 (1+x)/(x-1) where Qgen
(b) If heat loss QL*= θ-θ∞, show that at the limiting DIII,mod,
{1/θ} = 2 {(1/hc*) +1}1/2, and limiting DIII,mod is given by
DIII,mod = [{1/(2θ)}-1] exp (1/θ)/[ 1+ {1/(2θ)}]
Problem 15.7.
Consider the solution in text for non-dimensional speed for any order of reaction with fuel
Λ = {YF,02hc* )/2} /{∫ θ0 1 ( 1-θ) nF exp(-E*/θ) θα1-n1 dθ } (A)
Where Λ = AY {ρD / m " 2 } YO2 nO2 T∞ α1 (p /RT∞) n1[1 /hc*]nF How does this equation simplify
if nF=1 and α1=n1 ( Hint Chapter 05 for exponential integral).
Problem 15.8
The premixed gas mixture C3H8 and 50 % excess air flows at an average velocity of 25 cm/s
through Bunsen burner of dia 1 cm. Flow is assumed to be laminar. Determine the flash back
and blow off limits. Let T0=298 K; hc=46357 kJ/kg ( Lower HV); p= 1bar
assume λ=7.63E-05 kW/(m K); cp= 1.2 kJ(kg K); then ρD = λ/cp; A, PRE EXPONENTIAL
FACTOR (1/s):- 4.84E+09 for kmole/m^3 s of fuel which could be converted into AY
as 1.3e09; E= 125604 kJ/kmole, nF= 10.1; nO2= 1.65; alpa1= n1=0; d quench= 3.9 mm
Problem 15.9
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