1. What is Air Mass Flow Rate?

Definition: This calculator determines the mass flow rate of air based on volumetric flow rate and air density.

Purpose: It helps engineers and technicians calculate the mass of air moving through a system per unit time, which is crucial for HVAC, pneumatic systems, and process engineering.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( W \) — Mass flow rate (lb/hr)
• \( Q \) — Volumetric flow rate (GPM)
• \( \rho_{air} \) — Air density (lb/ft³)
• 60 — Conversion factor (minutes to hours)

Explanation: The volumetric flow rate is multiplied by air density to get mass per minute, then multiplied by 60 to convert to hourly rate.

3. Importance of Air Mass Flow Rate

Details: Accurate mass flow rate calculations are essential for system design, energy calculations, and process control in air handling systems.

4. Using the Calculator

Tips: Enter the volumetric flow rate in GPM and air density in lb/ft³ (default 0.561 lb/ft³ for standard air). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is standard air density?
A: Standard air density at 68°F (20°C) and sea level is approximately 0.075 lb/ft³, which converts to 0.561 lb/ft³ when accounting for the GPM to ft³/min conversion (×7.481).

Q2: How does temperature affect the calculation?
A: Higher temperatures decrease air density. For accurate results, adjust the density value for your specific conditions.

Q3: Can I use this for other gases?
A: Yes, but you must use the correct density value for the specific gas you're working with.

Q4: Why multiply by 60?
A: The factor converts the flow rate from "per minute" to "per hour" since there are 60 minutes in an hour.

Q5: What if my flow rate is in CFM instead of GPM?
A: You would need to adjust the density value accordingly or convert CFM to GPM first.