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Abstract :
In this experiment,we were able to estimate the head losses in different sorts of valves
and piping connections assembled in two separate hydraulic pipes circuits .Experimental
values of loss coefficient (K),the relation between friction coefficient (f)and Reynolds
number for a straight pipe,the relation between flow rate (Q)and head loss(h
L
)were
found. Their theoretical values were calculated and compared to the experimental
values.For instance,,the experimental relation (F= 0.4164Re
.4009
) was compared with
the literature value to produce an error % of( 406%)forb & 60% form.The value of K for
gate valve was 0.59 and the error was 195%, the K value for globe valve was 3.5 and the
error was 56% and we get the result from tables 1 to 6
And from graph 1 to 4.
Introduction :
In chemical processes, a lot of pipes connections are involved to carry the treated fluids.
During fluid transfer,a pressure loss exists due to the change in the flow phenomena such
as, a change in pipes diameter or flow direction which cause a resistance of fittings or
valves to let the fluid pass smoothly.Pressure loss in pipe circuit is sorted into one due to
the viscous resistance throughout the whole system and another due to fitting and pointed
effects .The overall loss is the sum of both.So,we can say the total loss can be different
than the sum of the losses of the separate components.By conducting this experiment,
we’ll be able to find the pressure losses across to different systems .Also, for the straight
pipe portion, the relations (f Vs Re)and(Q Vs h
L
) will be generated.
Theoretical Background :
For an incompressible fluid flowing through a pipe the continuity eq. (Q=V
1
A
1
=V
2
A
2
) is
applicable
.
The head loss in constant diameter straight pipe can be calculated from the expression:
(h
L
= 2f LV
2
/ gd ),while f is the friction factor = f (Re,roughness).
The head loss that is caused by a sudden expansion can obtained from the equation:
[h
L
= (V
1
 V
2
)
2
/2g],while the loss due to a sudden contraction is obtained from :
[h
L
= KV
2
2
/2g ]and K= f (A
2
/A
1
,Re).
The loss caused by bends is calculated by : [h
B
= K
B
V
2
/2g ],K
B
= f (bend and pipe
raduis,bend angle ).
The loss caused by a valve is calculated from ( h
L
=KV
2
/2g )while (h
L
= 12.6 x )
and K = f (valve type,valve degree of opening).
Usually , piezzometer tubes are used to measure the loss between 2 different heights
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 Fall '09
 M.Elgaily

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