Pump

Calculation of friction losses, power, developed head and available Net Positive Suction Head of a pump 1. +n the Tools menu! clic3 Options! then clic3 the Calculation ta& and tic3 on the  Iteration 2. In the spreadsheet "Calculations" a. Insert the parameter values in the cells C21-C40 (yellow cells) - If the pump is &elow the li%uid level in the suction tan3! 6 1 (cell C7$) is positive. If the - If If th there are not not en enlar lare emen ments or or co contr ntract action ions in in th the sy system! em! se set en enlar lare emen ment an andor or c &. 'urn the "I'C*" +, (set the value in the cell 1 (red cell) e%ual to 1 and press ,' c. Iterate (&y pressin ) until the value of " f " in the cell *1# is constant d. 'o recalculate recalculate for different different parameter values turn the "I'C*" + (set the value in th

%uations that are &ein used in the calculations Calculation of the annin friction factor " f " In laminar flow! &y usin the e%uation

f  =  =

16 Re

In tur&ulent flow! &y usin the Cole&roo3 e%uation

(

ε / D 1.255 1 =−4 log10 + 3 . 7 Re √ f  f  √ f 

)

Calculation of the friction losses In straiht pipes

In sudden enlarement

2

 ΔP L v h s= = 4 f   ρ  D 2

( )

he =

1−

2

 A 1

v12

 A 2

2 α 

In sudden contraction

hc = 0 . 5 5

( ) 1−

 A 2

2

v 22

 A 1

2 α 

 vaila&le  vaila&le ,et 5ositive uction *ead

 NPSH a =

 P− p v  ρg

 ΣF s

 z 1 −

+

g

&o8. +n Maximum iterations &o8 write 1000.

ump is a&ove the li%uid level in the suction tan3! 6 1 is neative ntraction coefficients in the cells C2# and C2$ e%ual to 0 /) cell 1 e%ual to 0 and press ,'/). /epeat steps 2a to 2c

Calculation of friction losses, reuired power, developed head and available NPSH of a pump

Input data low rate Inside diameter 5ipe lenth uction pipe lenth ;ensity >iscosity

m7h m m m 3m7 5as

9: ;i : <:
20 0.042 12 2 10=0 0.002

nlarement-loss coefficient

?e :

0

Contraction-loss coefficient

?c :

0.==

>alves-loss e%uivalent lenth


700

ittins-loss e%uvalent lenth


72

,um&er of valves

,v :

1

,um&er of fittins (0 o el&ows)

,f :

7

/afness of the pipe

raf :

0 m

>elocity at point 1

v1:

5ressure at point 1

51:

10172= 5a

5ressure at point 2

52:

10172= 5a

>apor pressure in the suction line

pv :

1274 5a

A 1

0 ms

;istance of point 1 from reference level

6 :

-2

;istance of point 2 from reference level fficiency of the pump

62:

$ #0@

n:

A If the pump is a&ove the li%uid level in the suction tan3! 6 1 is neative

I'C*:

!

;erived data Bass flow rate! Cross sectional area Bean velocity at point 2 /eynolds num&er /elative rafness Corection factor 

m˙ :  : vm2 : /e : rr :

=.$777 3s 0.0017 m2 4.010 ms $$41 0

α=

1

f#

$%$$&'

14.

14.#

e : c : :
0.00 4.42 12.0 4.07 107.2 !$'%)*

"esults riction factor

riction losses nlarement losses Contraction losses >alve-e%uivalent lenth ittin-e%uivalent lenth traiht tu&e losses Total friction losses

nery and 5ower added to the fluid &y the pump  1ws # /e%uired 5ower (&ra3e power) 12sr  # ;eveloped *ead  H #

D3 D3 m m D3 +-.

/!0%* D3

 12s #

!/&'%0 

12sr  #

!'*!%* 

H#

/!%* m

 vaila&le ,5* riction losses in the suction line -Contraction losses -ittin-e%uivalent lenth -traiht tu&e losses 'otal friction losses in the suction line

cs :

4.42 D3


1.74 m 12.0 D3 1#.$7 D3

NPSHa #

&%* m