1. What is the Boiling Water Evaporation Rate Equation?

The boiling water evaporation rate equation calculates the mass rate of water evaporation under boiling conditions. It considers the surface area, pressure difference, heat transfer coefficient, and latent heat of vaporization.

2. How Does the Calculator Work?

The calculator uses the evaporation rate equation:

Where:

• \( A \) — Surface area (m²)
• \( P_{sat} \) — Saturation pressure (Pa)
• \( P_{vap} \) — Vapor pressure (Pa)
• \( h \) — Heat transfer coefficient (W/m²·K)
• \( L \) — Latent heat of vaporization (J/kg)

Explanation: The equation calculates the mass flow rate of evaporating water based on the driving potential (pressure difference) and heat transfer characteristics.

3. Importance of Evaporation Rate Calculation

Details: Accurate evaporation rate calculation is crucial for designing boilers, heat exchangers, and distillation systems, as well as for energy efficiency analysis in industrial processes.

4. Using the Calculator

Tips: Enter all values in SI units. Ensure saturation pressure is greater than vapor pressure for valid results. All input values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical heat transfer coefficient for boiling water?
A: For nucleate boiling, h typically ranges from 2,500 to 35,000 W/m²·K depending on conditions.

Q2: How does pressure affect evaporation rate?
A: Higher pressure difference (P_sat - P_vap) increases evaporation rate, as does higher heat transfer coefficient.

Q3: What is latent heat of vaporization for water?
A: At 100°C, it's approximately 2,257 kJ/kg (2,257,000 J/kg).

Q4: Can this be used for other liquids?
A: Yes, but you must use the appropriate properties (P_sat, L) for the specific liquid.

Q5: What's the difference between P_sat and P_vap?
A: P_sat is the saturation pressure at given temperature, while P_vap is the actual vapor pressure in the system.