Bernoulli's Equation and fire hose

Click For Summary
SUMMARY

The discussion focuses on applying Bernoulli's Equation to determine the maximum diameter of a fire hose nozzle required to shoot water to a height of 35.0 meters. The flow rate is established at 0.500 m3/s, leading to the calculation of velocity using the formula v = √(2gh), resulting in a velocity of 26.2 m/s. The maximum radius is derived from the equation A = Flow rate / Velocity, which is then doubled to find the maximum diameter. Additionally, if a nozzle with double the diameter is used, the height the water can reach is recalculated using the same principles.

PREREQUISITES
  • Understanding of Bernoulli's Equation
  • Knowledge of fluid dynamics principles
  • Familiarity with the concept of flow rate
  • Basic algebra for solving equations
NEXT STEPS
  • Calculate the maximum diameter of a nozzle using the formula A = Flow rate / Velocity
  • Explore the implications of nozzle diameter on water pressure and height
  • Investigate the effects of varying flow rates on fluid dynamics
  • Learn about practical applications of Bernoulli's Equation in engineering
USEFUL FOR

Engineers, physics students, and anyone involved in fluid mechanics or hydraulic systems will benefit from this discussion.

ChemIsHard
Messages
15
Reaction score
0
A fire hose must be able to shoot water to the top of a building 35.0 m tall when aimed straight up. Water enters this hose at a steady rate of 0.500 m3/s and shoots out of a round nozzle.

i) What is the maximum diameter this nozzle can have?

ii) If the only nozzle available has a diameter twice as great, what is the highest point the water can reach?

I know that Flow rate=0.500 m3/s=A*V. I know the pressure needed to obtain this height from P=35*9.8*1000=3.43X10^5 Pa.

I know I should be applying Bernoulli's equation but I'm stuck. Any pointers are appreciated.
 
Physics news on Phys.org
I just had an idea.

P+1/2PV^2+Pgh=pgh+1/2pv^2+P

We can cross out both p's since they're both exposed to atmosphere. The first equation has no potential while the second has no kinetic.

1/2pv^2=pgh

v=root(2g(35m))
v=26.2 m/s

0.5=26.2*Pi(r^2)

Calculate for r then times by two for maximum diameter. Then just recalculate using the previous equation with 2r.

Looks good?
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 13 ·
Replies
13
Views
20K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 4 ·
Replies
4
Views
8K
  • · Replies 2 ·
Replies
2
Views
3K