Air at 80 °F is to flow through a 72 ft diameter pipe at an average velocity of 34 ft/s . What diameter pipe should be used to move water at 60 °F and average velocity of 71 ft/s if Reynolds number similarity is enforced? The kinematic viscosity of air at 80 °F is 1.69E-4 ft^2/s and the kinematic viscosity of water at 60 °F is 1.21E-5 ft^2/s. Round your answer (in ft) to TWO decimal places.

2.47  ft

Explanation:

Given that:

The initial temperature of air = 80°F

Diameter of the pipe = 72 ft

average velocity of the air flow through the pipe =  34 ft/s

The objective is to determine the diameter of the  pipe to  be used to move water at:

At a temperature = 60°F   &

An average velocity of 71 ft/s

Assuming Reynolds number similarity is enforced;

where :

kinematic viscosity (V_air) of air at 80 °F  (V_air)  = 1.69 × 10⁻⁴ ft²/s

kinematic viscosity of water  at 60 °F (V_water) = 1.21 × 10⁻⁵ ft²/s

The diameter of the pipe can be calculated by using the expression:

2.4686  ft

2.47 ft   ( to two decimal places)

Thus; diameter pipe to be use to move water at the given temperature and average velocity is 2.47 ft

hi

explanation: