An oil pipeline and a 1.3–m3 rigid air tank are connected to each other by a manometer, as shown in Fig. P3–149. If the tank contains 15 kg of air at 80°C. determine (a) the absolute pressure in the pipeline and (b) the change in Δh when the temperature in the tank drops to 20°C. Assume the pressure in the oil pipeline to remain constant, and the air volume in the manometer to be negligible relative to the volume of the tank.

Solution to 141P

Step 1 of 5</p>

In this question we need to determine the absolute pressure existing in the pipeline and the change in differential height when the temperature in tank drops to . We have to assume that the pressure in oil pipeline is constant and the volume of air present in air in the manometer is very less compared to volume of air in tank.

Given data:

Volume of air tank

Mass of air in air tank

Temperature of air tank,

Step 2 of 5</p>

From ideal gas equation,

is the pressure

is the volume

is the mass

gas constant of air,

is the temperature.

Calculate the pressure of air tank,

Specific gravity is calculated by the equation,

is the density of fluid

is the density of water

Step 3 of 5</p>

We need to write the combined pressure of the system,

Now, from the formula of specific gravity,

density of oil

density of mercury

Specific gravity of oil.

Specific gravity of mercury

..............(1)

Thus the pressure in pipeline is