Calculate discharge in L/s and Kg/s

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In summary, the specific gravity of oil is 0.80 and it is being discharged through a 30mm diameter pipe at a velocity of 12m/s. The discharge in L/s is 8.482300165 and in Kg/s is 6.785840132. However, the conversion of 1L=1Kg does not apply in this case as the density of the oil is 0.8kg per litre.
  • #1
Parsifal1
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Homework Statement


A tank contains oil with a specific gravity of 0.80, which is discharged through a 30mm diameter pipe at 12m/s. Calculate the discharge in L/s and Kg/s.

Homework Equations


specific gravity=density of oil/density of water
mass flow rate=volume flow rate*density
volume flow rate=velocity*area

The Attempt at a Solution


Density=(0.8*1000)=800 kg/m^3
Area=pi(0.015)^2=7.068583471*10^-4
Q=12*7.068583471*10^-4=8.482300165*10^-3
m=8.482300165*10^-3*800=6.785840132 kg/s

Shouldn't L/s be the same since 1L=1Kg?
 
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  • #2
Shouldn't L/s be the same since 1L=1Kg?
No. 1 L = 0.8 kg for this oil. Water has a density of 1 kg per litre. (All approximate.)
 
  • #3
Merlin3189 said:
No. 1 L = 0.8 kg for this oil. Water has a density of 1 kg per litre. (All approximate.)
So the answer is 6.785840132 Kg/s and 8.482300165 L/s?
 
  • #4
Yes.
But I would round these numbers to something sensible, like 2 sf. depending on the question's request. Since all the measurements are given to only 2 sf, you can hardly get a more accurate answer. If the question specifies that they are accurate to more figures, like RD = 0.8000 and pipe is 30.00mm and flow is 12.00 m/s even though these extra figures are not shown, then a more accurate answer would be appropriate.
 
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Related to Calculate discharge in L/s and Kg/s

1. How do I calculate discharge in L/s and Kg/s?

The formula for calculating discharge in L/s is Q = A x V, where Q is the discharge rate in L/s, A is the cross-sectional area of the pipe or channel in square meters, and V is the velocity of the fluid in meters per second. To convert L/s to Kg/s, you can use the density of the fluid in Kg/L. Multiply the discharge rate in L/s by the density to get the discharge rate in Kg/s.

2. What is the difference between L/s and Kg/s?

L/s is a unit of volume flow rate, while Kg/s is a unit of mass flow rate. L/s represents the amount of fluid passing through a specific point in a given time, while Kg/s represents the mass of the fluid passing through that point in the same amount of time. They are related by the density of the fluid, which is the mass per unit volume.

3. How does the cross-sectional area affect the discharge rate?

The cross-sectional area of a pipe or channel has a direct impact on the discharge rate. A larger cross-sectional area means there is more space for the fluid to flow, resulting in a higher discharge rate. Conversely, a smaller cross-sectional area means there is less space for the fluid to flow, resulting in a lower discharge rate.

4. What factors can affect the velocity of the fluid?

The velocity of the fluid can be affected by various factors, including the slope of the channel or pipe, the roughness of the channel or pipe walls, and the viscosity of the fluid. Changes in these factors can alter the flow rate and thus impact the velocity of the fluid.

5. Can the discharge rate vary over time?

Yes, the discharge rate can vary over time due to changes in the factors that affect flow rate, such as changes in the slope of the channel or pipe, or changes in the viscosity of the fluid. It is important to regularly monitor and calculate the discharge rate to ensure accurate measurements and efficient management of the fluid flow.

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