• Author / Uploaded
• أحمد صلاح الدين

• Categories
• Medida de presión
• Presión
• Densidad
• Cantidades fisicas
• Gases

Citation preview

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.1 The density of olive oil is 850 kg/m3. When a container of 2 kg mass and 20 litres internal volume is completely filled with the olive oil, what is the combined mass of the container and oil?

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.2 The density of an oil is 850 kg/m3. Find its specific weight and kinematic viscosity if the dynamic viscosity is 5 x 10-3 kg/ms.

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.3: A circular piston exerts a pressure of 80 kPa on a fluid, when the force applied to the piston is 0.2 kN. Find the diameter of the piston.

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.4:

A sealed container is completely filled with a gas at an absolute pressure of 3.37 bar. What is the gauge pressure of the gas?

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.5: A bottle is partially filled with wine as depicted in the diagram. If the gauge pressure at the liquid surface is -3000 Pa, What is the gauge pressure at 0.2 m below the surface (in Pa)? [Assume the liquid has a density of 1000 kg/m3)

Lecture 1-Properties of Fluid and Hydrostatic pressure

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.7

What is the water pressure on the sea bottom at a depth of 6500m? The specific gravity of sea water is assumed to be 1.03.

Lecture 2-Measurement of Pressure

Example 1.8: Figure shows the principle of the barometer, which is used to measure the pressure of the atmosphere. Assume the fluid in the barometer is mercury and its density is 13600 kg/m3, and the local atmosphere pressure Pa=1bar=1x105 Pa, calculate the height of column of mercury in mm.

Lecture 2-Measurement of Pressure

Example 1.9: A mountain lake has a maximum depth of 40m. The barometric pressure is 598 mmHg. Determine the absolute pressure (in pascals) at the deepest part of the lake (density of water is 1000 kg/m3 and density of mercury is 13600 kg/m3).

Measurement of pressure using manometers • U-tube manometer

• The pressures at equal elevations in a continuous mass of fluid at rest must be the same

𝑝𝐴= 𝑝1

𝑝2 =𝑝1+𝛾1ℎ1

𝑝2= 𝑝3

𝑝3=𝛾2ℎ2

𝑝A =𝑝1= 𝑝2 -𝛾1ℎ1= 𝑝3 -𝛾1ℎ1 = 𝛾2ℎ2-𝛾1ℎ1

If the fluid in A is gas, then 𝛾1 can be neglected

𝑝A =𝛾2ℎ2

Lecture 1-Properties of Fluid and Hydrostatic pressure

Example 1.10 (additional): A differential manometer contains water (density 1000 kg/m3). The manometer is connected between two points in a horizontal pipe carrying air (density 1.2 kg/m3). When the difference in levels is 54 mm, what is the pressure difference between the two point. Assume the density of air is neglected.

Please find the solution next page