- -
.
.
.
.
.
- 2 -
, , , , km , ..
, , , , km , .
- () (1-1) 3 .
pd - ps vd2 - vs2 Havail = + + y (1-1) 2g
pd vd ps, vs , y (1-1) . 3 , m.
- () . /sec, /min, /sec, gpm, cfs .
- () (;kg-m/kg) . .Q H Pw .
Pw = HQ (1-2)
Pw (water power) , kg-m/sec , 75kg-m/sec(HP) . , . (P) , KS .
p(%) = Pw/P = HQ/P (1-3)
(1.1) .
(1.1) ) ,
, , , .
- 3 -
(turbo) , (impeller) () .
- (centrifugal type) , (spiral or volute type) diffuser casing .
- () .
- (axial flow type) .
-
- , , (samlping
pump) (), , , ,
- ,
() () . 6m, 100m 200m .
1. () bucket . (2.1) , , . , .
(2.1)
- (2.2) , , . .
(2.2)
2. (Torricelli ) (2.3) 1m 760mm
- 4 -
, 0.101MPa. [0.101MPa=1.033kgf/, 13.6 760mm, 10.33m ] 760mm . 0 .
760mm
a
b
b
a
(2.3) Torricelli
, 8m 6m.
3. () . , , . . () . . . (2.1) .
(2.1) (1 )()
()
()
()
05
10
0.028850.025470.02268
152030
0.020500.018710.1607
4. 100 1
. 100 . , . (2.2), (2.3) . .
(2.2) () (m)
0 10 20 30 90100
0.0623 0.1251 0.2383 0.4326 7.149310.3323
(2.3) (m) (m)
0 100 200 300 5003,000
10.3310.2110.09 9.97 9.73 7.15
5. (2.4) 1 2 , , .
1
2
V1
V2
A1
p1r1
z1 z2
A2
p2r2
2.4)
v12 p1 v22 p2 -- + -- + z1 = -- + -- + z2 = const (2-1) 2g 2g
v,p,z, , , , . v2/2g , p/
- 5 -
, z . [ / = kgfm/kgf = m]
v2/2g (velocity head), p/ (pressure head), z (potential head) , v2/2g (dynamic pressure), p (static pressure) , (total pressure) . (2-1) (Bernoulli's equation) . 1 2 , 1 2 1 2 , (2-2) .
v12 p1 v22 p2 -- + -- + z1 = -- + -- + z2 + H (2-2) 2g 2g
H 1 2 .
6. . (2.5) 1 2 1 2 .
(2.5)
Hth , H (2-3) .
v12 p1 v22 p2 -- + -- + z1 + Hth = -- + -- + z2 + H (2-3) 2g 2g
Hth H H Hth = H+H (2-4)
.
v12 p1 v22 p2 -- + -- + z1 + H = -- + -- + z2 2g 2g p2 v22 p1 v12 H = (-- + -- + z2) - (-- + -- + z1) (2-4) 2g 2g H , kgfm/kgf=m (2-5) . (kgfm/kgf)(kgf/) = kgf/ .
v12 v22 -- + p1 + z1 + H = -- + p2 + z2 (2-5) 2g 2g
1. - , KS . (3.1) , , , , , . , , . 25/m 47m , 225kw, 86% , 40m 29.2/m, 230kw, 83% .
(3.1) 500400
- 6 -
, . 0 () 0 , . , , , . . ( = )
- (, , ) .
, , (), ( ), , ,
, , , , , , , .
, , , , .
(3.1)
N(rpm)
Q(/min)H(m)
Pw(kw)
P(kw)
(%)
12345....
. .
. ,
.
. () (6-0.05)
.
2. (Ns) , , . 3 2 Ns .
Ns = N [Q]1/2 / H3/4 (3-1)
, 1/2 , 1 .
Q=14/min, H=100m, N=1750rpm 1 Ns = 1750 [14]1/2 / [100]3/4 = 207 2 Ns = 1750 [14]1/2 / [50]3/4 = 348 1 Ns = 1750 [7]1/2 / [100]3/4 = 147 Ns Ns , Ns . Ns Ns . , .
3. Ns . Ns -
- 7 -
, 0 () . (3.2a), - Ns , Ns . (3.2b), - Ns , Ns .(3.2c)
(3.2)
4. , 2 , .
Q' N' D' --- = --- [---]3 (3-2) Q N D H' N' D' --- = [---]2 [---]2 (3-3) H N D
P' N' D' p --- = [---]3 [---]5 [---] (3-4) P N D p'
, P : , N : , D : , p : .
- , 20% .
1 (3-2,3,4) D'/D=1, p'/p=1 (3-5) . Q' = Q [N'/N] H' = H [N'/N]2 P' = P [N'/N]3 (3-5)
, Q,H,P Q',H',P' 1, 2, 3 .
- , . , . Ns . .
5. - (cavitation) 100 1 100 , . , . , , , . , , . . , .
- 8 -
- (NPSH ; Net Positive Suction Head) (NPSHav) (NPSHre) .
- (NPSHav) system NPSH .
NPSHav
NPSHav = hsv = ps/ - pv/ hs - fvs2/2g (3-6)
hsv : (m) ps : (kgf/ abs.) pv : (kgf/ abs.) : (kgf/) hs : () (m) [ (-), (+)] fvs2/2g : (m)
(3-6) NPSHav hs , .
NPSHav
0 (3-6) .
NPSHav hsv = 10 - hs - fvs2/2g (3-7)
(3.3)
NPSH ( )
(3.2) NPSH
4m
3m
ps : (kgf/abs) 1.0330 10
4 1.0330 104
pv : (kgf/abs) 0.0238 10
4 0.0238 104
: (kgf/) 998.2 998.2
hs : (m) - 4 + 3
fvs2/2g : (m) 0.7 0.5
hsv = ps/ - pv/ hs - fvs2/2g
hsv = 10.35-0.24-4-0.7 = 5.41m
hsv = 10.35-0.24+3-0.5 = 12.61m
[ 20, 0m ]
- (NPSHre) (NPSHre) . (3.4) NPSHre a-c' , Thoma .
(3.4)
NPSHre(Hsv) , Hsv Q,n (3-8) .
S = Q1/2/Hsv3/4 N (3-8)
, Q
- 9 -
1/2 . Q /min, Hsv m, N rpm S Ns 12001300 .
NPSHre ( Thoma ) H, Hsv Thoma() .
= Hsv / H = NPSHre / H (3-9)
, H . , . .
- [NPSHre(1+)] [NPSHav NPSHre(1+)] , 0.3( 1m) . NPSHre NPSHav . (3.4) 2 NPSH A , A , .
NPSHre .
(3.5) NPSHav NPSHre
( ) - ,
, NPSHav .
- NPSHav 1.3 NPSHre . -
. -
.
- .
- .
- .