1. What is Mass Flow Rate of Air?

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, default 0.561075)

Explanation: The volumetric flow rate is converted to mass flow rate by multiplying by air density and converting minutes to hours (×60).

3. Importance of Mass Flow Rate Calculation

Details: Accurate mass flow rate calculations are essential for system design, energy calculations, and ensuring proper operation of air-based systems.

4. Using the Calculator

Tips: Enter the volumetric flow rate in GPM and air density in lb/ft³ (default is 0.075 lb/ft³ × 7.481 = 0.561075). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why multiply by 60 in the formula?
A: The factor 60 converts the flow rate from "per minute" (GPM) to "per hour" (lb/hr) to match typical engineering units.

Q2: What's the standard air density value?
A: Standard air density is about 0.075 lb/ft³ at sea level and 70°F. The default value accounts for GPM to ft³ conversion (×7.481).

Q3: When would I need to adjust the air density?
A: Adjust for different altitudes, temperatures, or when working with compressed air systems where density varies.

Q4: How do I find the volumetric flow rate?
A: Measure using flow meters or calculate from system parameters like duct size and air velocity.

Q5: Can this be used for other gases?
A: Yes, but you must use the correct density value for the specific gas being measured.