Main burner Problem :-

Givens :-

= 35 kg/sAi = 0.07954 mTti = 1608.8293 kPti = 20.39919 bar Tte = 2010 kCd = 1.5 Mi = 0.311072 H = 0.31823 mAcomb. = 0.021134 m

=

= 1.4

Required :-

1- Length of the main burner .2- Total pressure loss .3- Combustion efficiency .4- Combustion stability Check.5- Equivalence ratio .6- Reference Area of the main burner “Aref ”.7- Reaction rate of combustion “ “ .

SolutionFor measuring the length of the main burner we have to make a length scaling using :

For n= 1.8 & = 1.4 ( hydrocarbon air mixture ).

Using data of an engine uses an annular combustion chamber like F100 that have the following data:

By using the above relation we can calculate the main burner length :

Lmb = 0.59266 m

To calculate the total pressure loss we have to obtain some parameters :

,

Then we can calculate the total pressure loss.

= 0.85135

For the reference area :

By comparison between other types of combustors :Type of combustor

Can 0.07 37Can-Annular 0.06 28

Annular 0.06 20

Aref. = 0.1505 m

For calculating the equivalence ratio :

&

By using “Liquid Propane “as a working fuel and it is characteristics is:

fActual =0.064078

fStich= 0.015806

= 0.24666 < 1.03

Then, we can calculate the reaction rate of combustion :

For < 1.03 : Take the positive sign .For > 1.03 :

Take the negative sign .

b = 528.381Then we can say :

= 31.537 So, measure the combustion efficiency by using burner efficiency chart :

= 98.5 %

Stability check :

Parameters that affect the combustion stability are :1- Mass flow rate .2- Combustion volume .

3- Pressure .

Combustion Loading Parameter :-

C .V. =Combustion volume = Lcomb Acomb

Lcomb = Lmb - Ldiff.

For : Ldiff = 0.26857 m Acomb = 0.021134 m

Combustion volume = 0.025993 m

CLP= 5.914368 10Then, by using the chart :

Our calculation in this problem gives us the point of CLP & the equivalence ratio in side the stable region of the chart and that mean the combustion is stable .