Calculating Flow Rate in a Varying Diameter Pipe: Oil & Water Density

[ATHMechanical]

Flow Rate through a pipe!

Oil flows along a horizontal pipe which varies uniformly in section from 100 mm diameter at A to 150 mm diameter at B. At A the gauge pressure is 126kN/m2 and at B 140 kN/m2. Find the flow rate in litres per second and kilograms per second. The density of water is 1000kg/m3 and the relative density of the oil is 0.8. could anyone help me find a possible solution to this Q? Thanks.

 

[timthereaper]

It all kind of depends on the things you can safely assume. Try Bernoulli's equation if you are able to assume all the prerequisites for it (e.g. inviscid flow, along a streamline, etc). Also, try showing a little more work you've done next time and you might get a better response.

 

[ATHMechanical]

I have tried Bernoulli's equation already but I need to find velocity at point A and B. Bernoulli's therom will only let me find one velocity if I have the other, but I have two unknowns. I am also assuming from the Q, it mentions the diameter of the pipe at point A and B which would therefore make it a circular pipe, and to calculate Q you need the cross-sectional area if I am not mistaken.

You may also calculate the Flow Rate by => (1/4)(3.14)(pipe diameter^2)(Velocity)
But I do not have the velocity. From this formula you can change it around to find Velocity but once again I do not have the Flow Rate.

Could you please help start this question...maybe I need two equations, to find velocity and area 1st and then use Bernoulli's therom to find flow rate.

Also thanks for your reply "timthereaper".

ATHMechanical.