Evaporation Rate Of Boiling Water Calculator

Evaporation Rate Formula:

\[ \text{Evaporation Rate} = \frac{P \times A \times (X_S - X)}{L \times \rho} \]

Pressure (P):

Surface Area (A):

m²

Saturation Humidity Ratio (X_S):

dimensionless

Ambient Humidity Ratio (X):

dimensionless

Latent Heat of Vaporization (L):

J/kg

Density (ρ):

kg/m³

Evaporation Rate:

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1. What is the Evaporation Rate Formula?

The evaporation rate formula calculates the mass flow rate of water vapor evaporating from a boiling water surface. This equation is fundamental in thermodynamics, heat transfer, and environmental engineering applications involving phase change processes.

2. How Does the Calculator Work?

The calculator uses the evaporation rate equation:

\[ \text{Evaporation Rate} = \frac{P \times A \times (X_S - X)}{L \times \rho} \]

Where:

\( P \) — Pressure (Pa)
\( A \) — Surface area (m²)
\( X_S \) — Saturation humidity ratio (dimensionless)
\( X \) — Ambient humidity ratio (dimensionless)
\( L \) — Latent heat of vaporization (J/kg)
\( \rho \) — Density (kg/m³)

Explanation: The formula calculates evaporation rate based on the driving force (humidity difference) divided by the energy required for phase change, scaled by pressure and surface area.

3. Importance of Evaporation Rate Calculation

Details: Accurate evaporation rate calculation is crucial for designing heat exchangers, cooling systems, distillation processes, and environmental studies involving water bodies and atmospheric moisture transfer.

4. Using the Calculator

Tips: Enter all parameters in consistent SI units. Pressure in Pascals, area in square meters, humidity ratios as dimensionless values, latent heat in Joules per kilogram, and density in kilograms per cubic meter. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical value for latent heat of vaporization of water?
A: At 100°C (boiling point), the latent heat of vaporization is approximately 2,257,000 J/kg.

Q2: How do humidity ratios affect evaporation rate?
A: Higher saturation humidity and lower ambient humidity increase the driving force for evaporation, resulting in higher evaporation rates.

Q3: What factors influence evaporation rate in practical applications?
A: Temperature, air velocity, surface area, pressure, and humidity differences are key factors affecting evaporation rates.

Q4: Can this formula be used for non-boiling water?
A: While derived for boiling conditions, similar principles apply to evaporation at lower temperatures with appropriate parameter adjustments.

Q5: What are typical evaporation rates for industrial applications?
A: Rates vary widely from 0.001 kg/s for small systems to over 100 kg/s for large cooling towers or industrial evaporators.