1. What is a Mass Flow Rate to Velocity Calculator?

Definition: This calculator converts mass flow rate (in pounds per hour) to velocity (in feet per second) using fluid density and cross-sectional area.

Purpose: It helps engineers and technicians determine fluid velocity when only mass flow rate is known, which is common in piping and HVAC systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V \) — Velocity (ft/s)
• \( W \) — Mass flow rate (lb/hr)
• \( \rho \) — Fluid density (lb/ft³)
• \( A \) — Cross-sectional area (ft²)

Explanation: The mass flow rate is converted to volumetric flow rate (by dividing by density), then divided by area and time conversion factor (3600 seconds/hour) to get velocity.

3. Importance of Velocity Calculation

Details: Knowing fluid velocity is crucial for proper system design, ensuring adequate flow while avoiding excessive pressure drops or erosion.

4. Using the Calculator

Tips: Enter the mass flow rate in lb/hr, fluid density (default 62.4 lb/ft³ for water), and cross-sectional area (default 1 ft²). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a 3600 in the formula?
A: This converts hours to seconds (1 hour = 3600 seconds) to get velocity in ft/s from flow rate in lb/hr.

Q2: What's a typical density for water?
A: Water at 60°F has a density of about 62.4 lb/ft³. This varies slightly with temperature.

Q3: How do I find the cross-sectional area?
A: For circular pipes, use \( A = \pi r^2 \) where r is the radius in feet.

Q4: Can this be used for gases?
A: Yes, but use the appropriate gas density which varies significantly with pressure and temperature.

Q5: What's a typical velocity range for water in pipes?
A: Generally 2-8 ft/s for water in most applications to balance flow and pressure drop.