Venturi meter - Problem 3 - Fluid Dynamics - Fluid Mechanics 1 | Summary and Q&A

TL;DR

Calculation of pressure difference between the inlet and throat of a vertical venturi meter given specific gravity, diameters, flow rate, and coefficient of discharge.

Key Insights

• 🤒 The problem involves a vertical venturi meter, indicating the direction of flow.
• 🤒 The pressure connection for measurement is located at the throat of the venturi meter.
• ⚾ The actual discharge is calculated using the coefficient of discharge and the theoretical discharge based on the areas of the inlet and throat.
• 🤕 The difference in piezometric head can be used to calculate the pressure difference between the inlet and throat.
• ❓ The specific gravity of the fluid affects the calculation of the pressure difference.
• 💦 The density of the fluid is found by multiplying its specific gravity with the density of water.
• ❓ The calculated pressure difference is 34.45 kilopascal.

Transcript

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Questions & Answers

Q: What is a venturi meter?

A venturi meter is a device used to measure the flow rate of a fluid in a pipe by creating a pressure difference between the inlet and throat sections.

Q: How is the actual discharge calculated?

The actual discharge is calculated using the formula: Q_actual = cd * Q_theoretical, where cd is the coefficient of discharge and Q_theoretical is the theoretical discharge based on the areas of the inlet and throat.

Q: How is the difference in piezometric head used to calculate the pressure difference?

The difference in piezometric head, represented by h, is equal to the difference in pressure, p1 - p2, divided by the density of the fluid and acceleration due to gravity.

Q: What is the specific gravity of the fluid in this problem?

The specific gravity of the fluid is given as 0.8, which represents its relative density compared to that of water.

Summary & Key Takeaways

• A vertical venturi meter with specific gravity 0.8 has inlet and throat diameters of 150 mm and 75 mm, respectively.

• The pressure connection at the throat is 150 mm above the inlet.

• The actual flow rate is 40 liters per second with a coefficient of discharge of 0.96.

• The problem requires calculating the pressure difference between the inlet and throat.