Q9CQ - College Physics (Urone)

Question

Some chimney pipes have a T-shape, with a crosspiece on top that helps draw up gases whenever there is even a slight breeze. Explain how this works in terms of Bernoulli’s principle.

Step-by-Step Solution

Answer

The T-shaped chimney pipe has a constriction in the middle of the crosspipe which creates a vacuum and withdraws gases from the gas pipe.

Step 1: Bernoulli’s principle

Bernoulli's principle states that the total energy of the fluid at any point inside the fluid is constant. The total energy is the sum of kinetic energy, pressure energy and potential energy. Interconversion of these three energies can take place, however, the total energy of the fluid remains constant.

Step 2: T-shaped chimney pipe

Figure 1: T-shaped chimney pipe

InT-shaped chimney pipe, a crosspipe is attached to the inlet pipe. The crosspipe has a larger cross-sectional area on both sides and a smaller cross-sectional area in the middle as shown in figure 1. 

Step 3: Working ofa T-shaped chimney pipe

The breeze of airpass through one of the ends of the crosspipe. The cross-pipe has a larger cross-sectional area at the ends and a smaller cross-sectional area in the middle. When the breeze of air pass from the larger cross-sectional area of the crosspipe to the smaller cross-sectional area, the kinetic energy of the air increases. As per Bernoulli's principle, the total energy of the air must remain constant. The total energy remains constant by lowering pressure energy. The pressure of the air inside the venturi is too less than the pressure inside the inlet pipe. The smoke,gases and other dust particles are withdrawn up from below due to this pressure difference. The T- shapes of chimney pipe uses the principle of entrainment.