Technical documentation and software quality assurance for project ...

€
€
€
€
€
C =1000exp( −100R)
+ 0.8
and the Richardson number,
( ) =
ξ D s
⎛
⎜
⎝
g
2 2
Ds u j
⎞
⎟
⎠
1
3
Ds €
ξ( Ds), based on
Chamberlain formula for the width at frustum tip, W2 , is
W2 = LB ( 0.18exp( −1.5R)
+ 0.31)
1− 0.47exp −25R
€
The surface area of the flame, A, is calculated as:
A = π
4 W1 2 2 ( + W2 ) + π
2 W1 + W ⎡
2 ⎢
⎣
( ) R L
€
27
D s
( ( ) )
⎛
⎜
⎝
2 + W 2 −W 1
The fraction of the heat, Fs radiated from the flame surface was determined from
experimental data and the curve is:
Fs = 0.21exp( −0.00323u j € ) + 0.11
2
2
⎞ ⎤
⎟ ⎥
⎠ ⎦
The view factor F is defined by Sparrow and Cess, equation 4-14:
dA cos β i cos β jdA
i
dFA − =
j dAi
A ∫A
2
j π r
j
where:
A is the area of the radiating surface,
j
dA i is the receiving element,
j
β i is the angle between the normal to the receiving element and the line between the
element and the radiating surface,
β is the angle between the normal to the radiating surface at a point and the line
j
between that point and the receiving element,
r is the distance between the point on the radiating surface and the receiving element.
For a radiating surface of area i
A and a receiving element of area j
dA , we can let
q' = incident radiation intensity per unit area, and
E' = emissive power per unit area,
so
1
2