1. What is the Boiling Water Evaporation Rate Equation?

The boiling water evaporation rate equation estimates the mass flow rate of water evaporating from a surface. It's based on the difference between saturation pressure and vapor pressure, surface area, and temperature.

2. How Does the Calculator Work?

The calculator uses the evaporation rate equation:

Where:

• \( E \) — Evaporation rate (kg/s)
• \( A \) — Surface area (m²)
• \( P_{sat} \) — Saturation pressure (Pa)
• \( P_v \) — Vapor pressure (Pa)
• \( R \) — Gas constant (8.314 J/mol·K)
• \( T \) — Temperature (K)

Explanation: The equation calculates the mass transfer rate based on the pressure difference driving force and thermal energy available.

3. Importance of Evaporation Rate Calculation

Details: Calculating evaporation rates is crucial for designing boilers, cooling systems, distillation processes, and understanding heat transfer in various engineering applications.

4. Using the Calculator

Tips: Enter all values in SI units. Temperature must be in Kelvin. The gas constant is pre-set to 8.314 J/mol·K but can be adjusted if needed.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between P_sat and P_v?
A: P_sat is the saturation pressure at the liquid temperature, while P_v is the actual vapor pressure in the surrounding environment.

Q2: How does temperature affect evaporation rate?
A: Higher temperatures increase P_sat exponentially (via Antoine equation) and thus dramatically increase evaporation rate.

Q3: What's a typical evaporation rate for boiling water?
A: At 100°C (373K) with 1 m² area, typical rates range from 0.1 to 1 kg/s depending on conditions.

Q4: Are there limitations to this equation?
A: This is an approximate equation. More accurate models account for convection, air flow, and humidity effects.

Q5: How do I convert °C to Kelvin?
A: Simply add 273.15 to the Celsius temperature (e.g., 100°C = 373.15K).