Question

Two pipes A and B are connected in parallel between two points. Pipe A is 150m long

and has a diameter off 15cm. pipe B is 100m long and has a diameter of 12cm. both pipes

have the same friction factor 0.018. A partially closed valve in pipe A causes discharge in

two pipes to be the same as shown in fig. Estimate the value of the valve coefficient. All

other minor losses can be neglected​

Answer 1

Answer:

Kl =18.62.

where, kl-valve coefficient.

Explanation:

since,both pipes having same discharges.

A1V1=A2V2.

Pi/4 (0.15)² V1= Pi/4 (0.12)² V2.

V2=(0.15/0.12)² V1.

V2=1.5625 V1.-----------(1)

loss in the valve will be kl (V1²/2g).

head losses are same in the Both pipes.

hence,

(f1 l1 V1 ²/2g d1)+kl (V1²/2g)= (f2 l2 V2 ²/2g d2).

get the equation (1) and substitute in the above formulae.

we get,

18+kl=36.62.

kl=18.62.(this is the valve coefficient for the given condition.)