Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion
Discussion Forum : Hydraulics and Fluid Mechanics - Section 1 (Q.No. 6)
6.
The diameter of the nozzle (d) for maximum transmission of power is given by (where D = Diameter of pipe, f = Darcy 's coefficient of friction for pipe, and l = Length of pipe )
Discussion:
36 comments Page 1 of 4.
Sia said:
8 years ago
For maximum transmission, H=3h,
where H=Total Supply Head,
h=head lost due to friction,
H=3h.
=>v^2/2g=3 flV^2/(2gD),
where, v=velocity at the nozzle end,
V=velocity in pipe.
=>Q^2/(a^2.2g)=3flQ^2/(A^2/2gD).
where a=nozzle area,
A=area of pipe,
=>3fld^4=D^5.
=>d= (D^5/(3fl))^(1/4).
where H=Total Supply Head,
h=head lost due to friction,
H=3h.
=>v^2/2g=3 flV^2/(2gD),
where, v=velocity at the nozzle end,
V=velocity in pipe.
=>Q^2/(a^2.2g)=3flQ^2/(A^2/2gD).
where a=nozzle area,
A=area of pipe,
=>3fld^4=D^5.
=>d= (D^5/(3fl))^(1/4).
(1)
Rajasekhar said:
9 years ago
Nozzle head = total head- loss of friction head.
For maximum efficiency, Total head H = 3 hf,
V2/2g = 2(4flv2/2gd),
V = Q/area and solving we get answer.
For maximum efficiency, Total head H = 3 hf,
V2/2g = 2(4flv2/2gd),
V = Q/area and solving we get answer.
Hitesh said:
1 decade ago
There's another formula for head loss by Darcy h = 8fLQ^2/^2D^5.
But I don't understand how they have used it to get the answer. Please anyone explain.
But I don't understand how they have used it to get the answer. Please anyone explain.
Tilak said:
6 years ago
The answer is (d^5/2fl)^1/4 where f is darcy friction factor. After correcting a step in @Sia's answer,
V^2/2g = 2 hf = 2 flV^2/ (2gD).
V^2/2g = 2 hf = 2 flV^2/ (2gD).
(1)
Vinay said:
1 decade ago
The loss due to friction is (1/3)rd of total head loss. Use this and continuity + Bernoulli equation to get the answer.
Ayyappa said:
1 decade ago
First you need to know what is the maximum power transmitted through pipe and then equate it to the Bernoulli equation.
Durga Prasad said:
6 years ago
@Sia.
Instead of 8fl you mention 3fl, which is the correct formula? Please explain.
Instead of 8fl you mention 3fl, which is the correct formula? Please explain.
(1)
Monex sharma said:
9 years ago
Solve using dimensional method.
=> f is unit less.
=> D^5/l has dimension L^4.
=> f is unit less.
=> D^5/l has dimension L^4.
Rudy said:
1 decade ago
Is this relate to the friction loss equation :
delta p = f l/d v2/2g.
delta p = f l/d v2/2g.
GM BHATTI said:
1 decade ago
When delta p = f l/d v2/2g. So how can we applied Bernoulli equation?
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