3.1.
. (, , ) .
( ) ( ).
() - ( ), .
, , , , .
() , , .. , , - .
. , , , . .
.
, .
, , .
l.
.
. ( ), .
, , .
.
, ( = const) ( ).
|
|
k =1,4.
. , , ,
pV n =const
, V =1/ρ - , n - , n =1 ( ) n =1,4 ( ).
, : z - ; p - ; ρ w 2/2 - .
,
p 0. ,
, , , . (ρ=1,25 /3, ν=14,9 2/ p =101,3 t =20C).
, . . .
. . . , dl
(15.1)
, (14.1)
(15.2)
: ω - , 2; G - , /; γ - , /3, (15.2)
(15.3)
p / γ = const (15.3)
(15.4)
(15.4) p 1 p 2, - 0 L (L - )
(15.5.1)
(15.5.2)
(15.5) G (p 1 - p 2) d. (15.5) G (p 1- p 2).
. () :
- ;
- .
D / D = ( 1 + 2)/2.
|
|
(D / < 5%), , ; () .
(D / >5%) , .
3.2.
.
D p - .
ρ g (z 1- z 2) , . , , D z = 20, , , D =25 000 .
ρ g D z =1,2 /3.9.81.20 = 240 , 0,01 D , , , ρ g D z .
(15.6)
.. . (/2)
(15.7)
(15.8)
ρ = /(RT) - , /3 [ = ( 1 + 2)/2; p 1 2- ].
(15.7) (15.8) ρ w 2 /2 .
(15.7)
(15.9)
R - ( 1 ); R i T R = ρ gi T, i T .
. ,
(15.10)
(15.10) λ = 0,11(k / d + 68Re)0,25, , .. ,
(15.11)
D - , . . .; l - , ; k - , ; d - , ; ν - , 2/; Q - , 3/; - , /3 ( 0 760 . .).
. k / d << 1922 d v / Q ( ), (15.11)
(15.12)
w <3 /.
k / d >> 1922 d ν / Q ( ),
, k =0,1
. () , (15.7) d ,
(15.13.1)
λ .. ,
|
|
(15.13.2)
( , .) , , , , ; Re.
3.3.
. ( , ), .
, .
, .
, ρω w = const pw = const ω = const. (. . ), , , , .
, , .. z 1- z 2 ( ), .
, , D = 1- 2 = 196 000 ( 1=294 000 ); D z = z 1- z 2=20 ; w 1=20 /; w 2 = 25 /; t =27=300 ; R =287 /(.).
, 500 300 .
, , . ( , )
- dp = dp T. (15.14.1)
- (14.13)
(15.14.2)
, , . . ρ = f (l); w = f 1(l); λ = f 2(l). , . , , . ( ), . , .
, λ = f (Re; k / d). ( k d).
G - .
. ( ), , . , .
|
|
(6.52) w 1 . w ρ w 1 ρ1 w = w 1ρ1 / p. (15.14),
(15.15)
,
(15.16)
(15.15)
(15.17)
1 2(p 2 - ),
(15.18)
(15.18)
(15.19)
(15.20)
, (15.18),
(15.21)
(15.21) - , D p / p 1. ,
D p / p 1 < 5%, (14.22)
2,5%, .
, , 1, - , .
. , ,
(15.23)
, (14.18) λ= 0,11(k / d + 68Re)0,25 (. 8.2.2), ( 0 0,1 ), , .. ,
(15.24)
p 1 p 2 - , ; L , ; d - , ; k - , ; γ- , /3; Q - , 3/; ν - , 2/.
γ, Q ν . (15.24) , .
, k / d << 1922 d ν / Q k / d >> 1922 d ν / Q, (15.24)
(15.25)
(15.26)
(15.26), , (w >50 /).
. l , . , l
(15.27)
d .
l
(15.28)
d - .
l (15.27) (15.28) (15.23) () d, G ( ):
(15.29)
(15.30)
(15.29) (15.30) .
3.4.
. - . , .
- .
, , . ( 10 60 /), .
, , . - , , , , (, , ).
|
|
, , , , - .
.
, μ, R λ. ( 1 ) , λ Re .
(, ) , .
. , .
, . , 70 , .
( ) ( ).
1500 , 2000 .
5%, - 35% (, ) .
, , . , .
( ) , 25%.
, , , (, , , ).
, , , .
, , , .
, , 30 /, 20 /.
. .
, , .
, , , .
80 / (30 / ) ; 60 / (20 / ) .
, , , .
, 20 % , .
, , 10 % .
15%.
, .
, , , . , , .
, ( ) .
, , 1. 20-25%.
. . , 2.04.07-86 .
. , .
Δ , , ( ) ,
(15.31)
R - ( , ), /; l - , ; Z - , .
Δ ,
(15.32)
n - ; Σ l - , .
, . , . = 2000 .
(15.33)
0,9 - , .
n 0,65, - 0,8. (15.33) , (15.32).
.
, (. 15.1), .
, . 15.1. .
. 15.1.
15.1
, | , / | |
70 | 30 | |
20 | ||
70 | 80 | |
60 |
3.5. ()