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  • Jun 11, 2009, 12:41 PM
    Speedy46
    Velocities
    A pipe of 150mm bore is delivering water at a rate of 7500 liters per min at a pressure of 820kpa it connects via a horizontal gradually expanding pipe to a main of 300mm in diameter. Calculate the fluid velocity both in the main body of the pipe and at the outlet.

    Equation p1 * P2 / T1

    Any help would be great.

    Thanks in advance
  • Jun 11, 2009, 12:53 PM
    Perito

    Flow is the cross sectional area times the logitudinal flow rate (length/time).

    Cross sectional area where r is the radius of the pipe.

    You know the flow in liters/min. Convert liters to . (1 liter = 0.001 m^3). Convert the radius from millimeters to meters so that you're in the same dimensions. Divide the volumetric flow rate by the cross sectional area. The velocity will be in meters/min.



    The pressure is irrelevant insofar as this is concerned since you know the volumetric flow rate.
  • Jun 12, 2009, 02:51 AM
    Speedy46
    I converted the flow rate from 7500 litters per min to 7.5m^3

    I then worked out the cross sectional area being for 150mm diameter is 0.017 &
    for the 300mm diameter pipe 0.070

    so for 150 mm diameter I get 441.17 m/mm

    and for 300mm diameter I get 10623 m/mm

    Is this correct.
  • Jun 12, 2009, 07:25 AM
    Perito

    Quote:

    A pipe of 150mm bore is delivering water at a rate of 7500 liters per min at a pressure of 820kpa it connects via a horizontal gradually expanding pipe to a main of 300mm in diameter. Calculate the fluid velocity both in the main body of the pipe and at the outlet.
    150 mm = 0.15 m; r = 0.075 m





    ----------------------------------------------------

    300 mm = 0.3 m; r = 0.15 m



    The linear velocity in the larger pipe must be lower than the linear velocity in the smaller pipe.

  • Jun 12, 2009, 07:32 AM
    Speedy46
    Thanks for the help very pleased thank you.

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