Final answer:
Option 1: True is correct because laminar flow meters are used to measure low flow rates of air where the flow is smooth and orderly, typically when the Reynolds number is below 2000.
Step-by-step explanation:
To measure low flow rates of air, a laminar flow meter is indeed often used, so the correct option is Option 1: True. Laminar flow refers to a flow regime characterized by smooth parallel layers of fluid that do not mix. This behavior occurs at low velocities and can be predicted when the Reynolds number (NR) is below 2000. Such conditions are favorable for laminar flow meters, which are designed to measure the flow rate accurately without interference from turbulent eddies.
For instance, if an air conditioning system has a volume flow rate of Q = 3.84 × 10-3 m³/s and if it's within the laminar flow regime, calculating the Reynolds number would be the next step to confirm the flow type. If the Reynolds number is lower than 2000, the assumption of laminar flow is valid. However, if the velocity increases and the Reynolds number exceeds 3000, the flow would become turbulent, and a laminar flow meter would no longer provide accurate measurements.