10 / 12
Fig. 10. Dependency of the efficiency criterion
K
Q
on the fins height for various
angles
β
and finning pitch ratios
ˉ
t
(
Re
= 10
4
):
а
— are curves
1
(
β
= 30
◦
) — —
t
= 2
; —
t
= 4
;
N
—
t
= 10
; curves
2
(
β
= 45
◦
) —
×
—
t
= 2
;
∗
—
t
= 4
;
•
—
t
= 10
at Bi = 0.04;
b
— are curves
1
(
β
= 30
◦
) — —
t
= 2
;
—
t
= 4
;
N
—
t
= 10
; curves
2
(
β
= 45
◦
) —
×
—
t
= 2
;
∗
—
t
= 4
;
•
—
t
= 10
at Bi = 0.4
The increase in the CC height as compared to the reference channel
was calculated, as it is usually done for the conventional finned channel,
in the following way:
h
=
h
h
sm
=
h
0
K
hp
,
where
h
0
=
η
1
/
3
ξ
is a relative increase in the height of the non-finned
channel related to the convective heat release intensification,
K
hp
= (
k
D
cos
β
)
−
m
+2
3
t
t
−
1
t
+
h
−
1
t
1
−
m
3
is the height increase coefficient for the finned channel, here
h
=
h/δ
f
=
= (
h
1
+
h
2
)
/δ
f
is determined by a sum of heat-releasing and shaping fins
ISSN 0236-3941. HERALD of the BMSTU. Series Mechanical Engineering. 2015. No. 2 53