:
1) L = 780 ;
2) ΔΖ = - 38 ;
3) / Gr = 20,8106 /;
4) tp = 0,5 C;
5) / 20 ρ 20 = 820 /3;
6) 20 ν 20 = 6,410-6 2 /,
50 ν 50 = 3,810-6 2 /;
7) h .. = 35 ;
8) N = 1;
9) { P } = 7,4 .
.
/ (2.1)
r = 820 - (1,825 - 0,001315×820)×(0,5 - 20) = 805/3.
(2.2)
lglg (ν + 0,8 ) = 6,52 - 2,67× lg 273,5,
ν = -0,8 = 58,2×10-6 2 /,
a b (2.4)
,
a = lglg (6,4+0,8) - (-2,67) lg 293 = 6,520.
(2.1)
= 3228 3 / = 0,897 3 /.
(2.2)
,
W = 1,75 / Q = 3228 3 / (. 4.1).
. 4.1.
(. 1.1) D = 820 .
17IC σ = 520 (. 1.1).
m, n, 1 : n = 1,15;
= 0,9; 1 = 1,47; = 1,0.
(2.6)
Q = 3228 3 /(. 1.2):
- 3600-230 3600 3 / 230 ;
- 3600-78 3600 3 / 78 .
3600-230 3600-78 . 3.
, ,
h = 250 h = 82 .
, (2.4)
= 885×9,81×(3×250 + 82)×10-6 = 7,22 < 7,4 .
(2.5)
.
17IC D = 820 (. .1.1) δ = 11 .
(2.7)
D = 820-2×11=798 .
(2.8)
.
(2.9)
.
.
Re Re1, , - .
(2.12)
.
(2.10) :
.
(2.4) , (2.16)
= 3×250 = 750 .
|
|
(2.21)
.
I.
, .. n = 6.
Q = 3228 3 /(. Q - H, 3) (2.19) :
= 6×3×250+82 = 4582 ,
= -40 + 1,2×0,00499×780×103 + 35 = 3967 .
> , - .
(2.20)
n H = -40 + 1,2×0,00499×780×103 82 + 35 = 3885 ,
, (2.22)
.
, (2.23),
(2.19) :
6×3×215,8 + 82 = -40 + 1,2×0,00499×780×103 + 35 (3967 = 3967 ).
(2.24):
.
= 420 .
(.. 7 %).
10 %, 6 .
II.
, n = 5.
Q = 3228 3 / (2.19) :
= 5×3×250 + 82 = 3832 ,
= -40 + 1,02×0,00499×780×103 + 35 = 3967 .
> , .
(2.27, 2.28) i :
i = 0,00499 × .
m 0,25.
(2.26):
.
(2.15):
^ = D Z + 1,02 i (L p ) + 1,02 i × + 35 = -40 + 1,02×0,00499×780×103 1,02×0,00499×38460 + 1,02×0,001484×38460 + 35 = 3829 .
, = ^, .
. . 4.2 . 4.3.
. 4.2. 1
. 4.3. 2
1. .., .. . . .: 2002, . I, II.
2. .., .. . .: , 1981.
3. .., .. , . .: , 1965.
4. 2.05.06.-85*.
1
1.1