1. What is an Air Flow Rate Sensor Calculator?

Definition: This calculator estimates the volumetric flow rate (in GPM - gallons per minute) based on velocity and cross-sectional area measurements from an air flow sensor.

Purpose: It helps engineers and technicians convert sensor readings into practical flow rate measurements for HVAC systems, industrial processes, and ventilation systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Volumetric flow rate (gallons per minute)
• \( V \) — Velocity of air (feet per second)
• \( A \) — Cross-sectional area (square feet)
• 448.83 — Conversion factor (ft³/s to GPM)

Explanation: The velocity measurement from the sensor is multiplied by the duct area and conversion factor to get flow rate in GPM.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate measurement is critical for system efficiency, proper ventilation, and process control in industrial applications.

4. Using the Calculator

Tips: Enter the velocity reading from your sensor (ft/s) and the cross-sectional area of the duct (ft²). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why 448.83 as the conversion factor?
A: This converts cubic feet per second to gallons per minute (1 ft³/s = 448.83 GPM).

Q2: What's a typical velocity range for HVAC systems?
A: Typically 500-1200 ft/min (8.3-20 ft/s) for main ducts, lower for branch ducts.

Q3: How do I measure duct area?
A: For round ducts: \( \pi \times r² \). For rectangular ducts: width × height.

Q4: Can I use this for liquid flow?
A: Yes, the same formula applies to incompressible fluids like water.

Q5: How accurate is this calculation?
A: Accuracy depends on your sensor measurements and proper duct area calculation.