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heights, as the increase in the height is determined only by hydraulic losses

of the whole channel,

k

D

=

D

1

+

h

D

1

+

h

3

is a correcting factor for the channel

mean diameter change, having little effect on the final result.

The height increase coefficient determined by finning in the turbulent

flow mode (

n

= 0

.

8

;

m

=

0

.

25

) will constitute

K

hf

= (

k

D

cos

β

)

0

.

583

×

×

t

+0

.

583

(

t

+

h

1)

0

.

417

(

t

1)

and, as it was shown above, it can

grow within the investigated range of parameters up to values 1.15. . . 3.5,

which should be taken into account when designing the chamber thermal

protection.

Conclusions.

By using the coplanar flows in the cooling channels, their

energy efficiency will be significantly increased with regard to the firewall

heat release, mostly due to the increase in the convective component

as compared to the conventionally finned channels with the insufficient

efficiency.

By changing such finning parameters as the fins intercrossing angle

2

β

,

the Biot number, the relative finning pitch ratio

h

1

within the reasonable

and acceptable bounds, the thermal hydraulic efficiency can be controlled,

as well as the desired level of heat release and the thermal state can be

achieved for the structure.

CC efficiency estimation with regard to the

K

Q

criterion can be based

on the previously developed methodology for the classic finned channels

allowing for the actual effective area of finning on the heat-releasing

surface.

REFERENCES

[1] Aleksandrenkov V.P. Efficiency of heat transfer intensification in circular finned

cooling circuits of combustion chambers.

Vestn. Mosk. Gos. Tekh. Univ. im. N.E.

Baumana, Mashinostr.

[Herald of the Bauman Moscow State Tech. Univ., Mech.

Eng.], 2013, no. 3, pp. 111–121 (in Russ.).

[2] Kudryavtsev V.M., Orlin S.A., Posnov S.A. Experimental research of flow resistance

in circuits with complanar channels.

Izv. Vyssh. Uchebn. Zaved., Mashinostr.

[Proc.

Univ., Mech. Eng.], 1983, no. 4, pp. 54–58 (in Russ.).

[3] Pelevin F.V., Il’inskaya O.I., Orlin S.A. Engineering application of coplanar channels.

Vestnik PNIPU. Aerokosmicheskaya tekhnika

[PNRPU Aerospace Engineering

Bulletin], 2014, no. 2 (37), pp. 71–85 (in Russ.).

[4] Orlin S.A., Posnov S.A. Experimental research of heat transfer and flow resistance

in circular ducts with complanar channels.

Trudy MVTU im. N.E. Baumana

[Proc.

Bauman MSTU], 1984, no. 417, pp. 9–12 (in Russ.).

[5] Kirillov P.L., Yur’ev Yu.S., Bobkov V.P., ed. Spravochnik po teplogidravlicheskim

raschetam. Yadernye reaktory, teploobmenniki, parogeneratory [Reference book

on thermal and hydraulic calculations. Nuclear reactors, heat exchangers, steam

generators]. Moscow, Energoatomizdat Publ., 1990. 360 p.

54

ISSN 0236-3941. HERALD of the BMSTU. Series Mechanical Engineering. 2015. No. 2