Air Flow & Blow dryer

Objective:

To understand and measure the difference in the rate of flow of air when it is made to pass through  a specific pathway/ducting versus when it is spread over a larger generalized space

Outcome:

Students will comprehend the fact that ducting improves the flow of air which is useful for designing both passive and energy-efficient active cooling in building structures

Requirements:

Blow dryer, digital anemometer, plier (to hold the blow dryer), 1 m long PVC pipe having diameter equal to or just greater than the mouth of blow dryer, a table.

Prerequisites:

A conceptual knowledge of flow of air.

Procedure:

Step 1: Clamp the blow dryer with the plier.

Step 2: Place the plier on the table such that the air stream coming out from the blow dryer is parallel to the table.

Step 3: Place the anemometer 1 metre apart from the mouth of the blow dryer such that it is collinear with the axis of air stream coming from the mouth of blow dryer.

Step 4: Note the air flow rate from the anemometer in km/hr.

Step 5: Place a PVC pipe at the mouth of the blow dryer.

Step 6: Place the anemometer at the other end of the pipe.

Step 7: Note the air flow rate from an anemometer in km/hr.

Step 8: Compare the air flow rate in both cases.

Air Flow Rate (Without Pipe)(km/hr)	Air Flow Rate (With Pipe)(km/hr)

Step 9: Try the same demonstration with a bent pipe. Does the rate of flow of air change? How much? What can we learn from this? 

Step 10: Discuss examples of where this principle has been applied in general and specifically in buildings

References:

Case 1:

Case 2: