Hydraulics, Flow rate from Bernoulli Equation

In summary, the conversation discusses the calculation of flow rate in a Venturi meter for petrol with a specific gravity of 0.85. The diameters of the meter are given as 0.2m and 0.15m. The height difference in the manometer of mercury with a specific gravity of 13.6 is also provided as 0.012m. Using the Bernoulli equation and the equation U=Q/A, the values are inserted and equated, resulting in the answer of 39.3 l/s for the flow rate, which is equal for both Q1 and Q2. The values 0.093 and 0.058 are calculated from 2g x A after substituting u
  • #1
warrio1010
8
0

Homework Statement


Flow rate in Venturi meter of Petrol (SG 0.85).

Diam1 - 0.2m Diam2 - 0.15m

Height Diff in manometer of Mercury (SG 13.6) 0.012m, so Δp= 13600 x 9.81 x 0.012 = 1601?

Cd = 0.98

Homework Equations


Bernoulli,
p/ρg + U2/2g + Z

U=Q/A


The Attempt at a Solution



Inserting and equating the values into bernoulli i ended up with,

0.192 = Q22/0.093 - Q12/0.058

Not sure if this i right because i can't seem to go anywhere from here.

THE GIVEN ANSWER IS 39.3 l/s

Thanks a lot for any help.
 
Last edited:
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  • #2
Q1 equals Q2. How are the numbers 0.093 and 0.058 computed?
 
  • #3
They are calculated from 2g x A after subbing u for Q/A.
 

1) What is the Bernoulli Equation and how is it related to hydraulics?

The Bernoulli Equation is a fundamental equation in fluid mechanics that describes the relationship between pressure, velocity, and elevation in an incompressible fluid. It is commonly used in hydraulics to calculate flow rate and pressure changes in pipes and channels.

2) How is flow rate calculated using the Bernoulli Equation?

The Bernoulli Equation can be rearranged to solve for flow rate, which is calculated by dividing the change in pressure between two points by the fluid's density and the gravitational constant. This formula is known as the Bernoulli's equation for incompressible flow.

3) What factors affect the flow rate in hydraulics?

The flow rate in hydraulics can be affected by several factors, including the diameter of the pipe or channel, the fluid viscosity, the pressure difference between two points, and the roughness of the pipe surface. These factors can impact the friction and resistance within the system, ultimately affecting the flow rate.

4) How does the Bernoulli Equation relate to the conservation of energy?

The Bernoulli Equation is an expression of the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another. In hydraulics, the Bernoulli Equation demonstrates the conversion of potential energy (elevation) to kinetic energy (velocity) and vice versa in a fluid system.

5) What are some real-world applications of the Bernoulli Equation in hydraulics?

The Bernoulli Equation has numerous applications in hydraulics, including calculating flow rate in pipes and channels, designing pumps and turbines, and predicting pressure changes in fluid systems. It is also used in the design of aircraft wings and propellers, as well as in the study of weather patterns and ocean currents.

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