237 posts
TimePosted 29/11/2012 06:49:42
xxxx says

### calculation of flame momentum of a multi channel burner

Dear all

We can not directly measure how much is the distribution of axial air , radial air , stablizing air & transport air of the burner.

Than how can we calculate accurately the flame momentum of a bulti channel burner?

One way is measure the static pressure in each channel like

Presssure in Axial

pressure in radial

Pressure in stablizing Air

Pressure In transport Air

Than calculate the velocity in each channel by 4*sqrt(pressure) = m/s

Now we can measure separate (1) transport air (2) Axial Air (3) total Primary Air blower Air

but not th eradial & stablizing air

Now tell me how to calculate the flame Momentum in this case.

Please send me an excel sheet if possible.

Also transport air is also a part of flame , so during % primary air Calculation , transport air should be included ,normally people do not include the transport air in flame momentum calculation ? Why?

Please do reply

engr

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79 posts
TimePosted 30/11/2012 04:04:32
chari says

### re calculation of flame momentum of a multi channel burner

Please check the attached xls sheet, it may help you

chari

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237 posts
TimePosted 30/11/2012 10:03:56
xxxx says

### re calculation of flame momentum of a multi channel burner

Dear chari

Thanks a lot for the excel sheet but some doubts are there

1. In % PA Transport air is not considered

2.Radial Air flow is also not considered in the Momentum

3.In the coal transport air measurement what is the use of suction temp. & pressure for flow measurement

4.What is flow function?

5.Is there any impact in flame momentum calculation if the axial & radial air (both)dampers are partially closed.

6. In the velocity calculation of primary air you have used

velocity = 4.43*sqrt(dp/density)* static pressure but

in my openion  it should be

velocity = 4.43*sqrt(dp/density)

7. How is the calculation of nozzle velocity? Please do explain.

8.What is the meaning of Nozzle coefficient?

Waiting

Engr

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79 posts
TimePosted 03/12/2012 12:03:36
chari says

### re calculation of flame momentum of a multi channel burner

Dear xxx

Velocity is also always equle to pitot tube constant x sqrt( 2 * 9.81 * dp/density)

square root of 2 * 9.81 =4.43

so velocity = Pitot tube constant x 4.43 x sqrt(dp/density)

static pressure is not taken for finding the velocity,

static pressure and temperture of gas is taken into consideration to find the density of the fluid.

velocity of tip is found by flow in m3/sec divide by the tip area in m2..

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