Flow rate/pressure in a venturi

In summary: As the flow rate increases, the velocity in the constricted section also increases, causing a decrease in pressure according to Bernoulli's principle. This in turn creates a pressure difference between the non-constricted and constricted sections, with the pressure being lower in the constricted section. Therefore, as the flow rate increases, the pressure difference between the sections of the venturi also increases.
  • #1
GBA13
73
0

Homework Statement


Hi Guys,

I have found that as flow rate increases the pressure difference in the sections of the venturi increases. Would someone please mind explaining in words why as I'm not sure.

Homework Equations

The Attempt at a Solution


Well I know that when the fluid gets to a constricted section the velocity increases and the pressure decreases but I'm not sure why the pressure difference between the non constricted section and the constricted section increases with increased flow rate.

Thanks very much
 
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  • #3
  • #4
GBA13 said:

Homework Statement


Hi Guys,

I have found that as flow rate increases the pressure difference in the sections of the venturi increases. Would someone please mind explaining in words why as I'm not sure.

Homework Equations

The Attempt at a Solution


Well I know that when the fluid gets to a constricted section the velocity increases and the pressure decreases but I'm not sure why the pressure difference between the non constricted section and the constricted section increases with increased flow rate.

Thanks very much
Think Bernoulli: p + ρv2 = constant if there is no change in potential energy
 

What is a venturi?

A venturi is a device that is used to measure or control the flow rate or pressure of a fluid. It consists of a narrow section or throat in a pipe that causes the fluid to accelerate, followed by a wider section that causes the fluid to decelerate. This change in velocity creates a pressure difference, which can be used to measure or control the flow rate of the fluid.

How does a venturi work?

A venturi works by creating a constriction in a pipe, which causes the fluid to accelerate as it passes through the narrow section. This acceleration results in a decrease in pressure, which can be measured using a pressure gauge. The fluid then decelerates as it passes through the wider section, causing the pressure to increase. This change in pressure can be used to calculate the flow rate of the fluid.

What is the equation for calculating flow rate in a venturi?

The equation for calculating flow rate in a venturi is Q = A1V1 = A2V2, where Q is the flow rate, A is the cross-sectional area, and V is the velocity. In a venturi, the cross-sectional area decreases at the throat, causing the fluid velocity to increase. The flow rate remains constant throughout the venturi, so by measuring the velocity at different points, the flow rate can be calculated.

What factors affect the flow rate in a venturi?

The flow rate in a venturi can be affected by several factors, including the pressure difference between the two ends of the venturi, the diameter of the pipe, and the viscosity of the fluid. A larger pressure difference or a smaller pipe diameter will result in a higher flow rate, while a more viscous fluid will have a lower flow rate.

What are some applications of venturi flow measurement?

Venturi flow measurement is commonly used in various industries, including water treatment, chemical processing, and oil and gas. It is used to accurately measure and control the flow rate of fluids, which is crucial for maintaining efficient and safe processes. Venturis are also used in carburetors for measuring the flow of air into an engine, and in respiratory devices for measuring the flow rate of oxygen or other gases.

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