# Calculating discharge on the pipe diameter and the pressure? [closed]

Is it possible to сalculate discharge / flow rate on the pipe diameter and the pressure (for constant pressure)?

For example:

Pressure_internal = 5 bar, Diameter_pipe = 36 mm, Density_water = 1000 kg/m^3

Bernoulli's Formula:

$$\frac{\rho v^2}{2} + \rho g h + p = const$$

$$v \approx \sqrt{(p_i-p_a)\frac{2}{\rho_w}} = \sqrt{(5 \mathrm{bar}-1 \mathrm{bar})\frac{2}{1000 \frac{\mathrm{kg}}{\mathrm{m}^3} }}=28.284 \frac{\mathrm{m}}{\mathrm{s}}$$

Then the discharge should be:

$$Q = Sv = (\pi r^2) v = \pi * (18\mathrm{mm})^2 *28.284\frac{\mathrm{m}}{\mathrm{s}} = 1717.81 \frac{\mathrm{l}}{\mathrm{min}}$$

But these values are very far from reality. How can I perform a calculation correct?

• If you are asking for help in doing a calculation, first you need to state the conditions of the problem. It is difficult to comment without understanding what the situation is. – sammy gerbil Mar 1 '17 at 8:15