Modified Heat Of Vaporization Calculator

Modified Heat of Vaporization Formula:

\[ \lambda = (h_{fg} + (c_{pv}) \times \frac{(T_w - T_{Sat})}{2}) \]

Latent Heat of Vaporization (h_fg):

J/kg

Specific Heat of Water Vapor (c_pv):

J/kg·K

Plate Surface Temperature (T_w):

Saturation Temperature (T_Sat):

Modified Heat of Vaporization (λ):

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1. What is Modified Heat of Vaporization?

Modified Heat of Vaporization is defined as the heat required to change one mole of liquid at its boiling point under standard atmospheric pressure, accounting for additional thermal effects.

2. How Does the Calculator Work?

The calculator uses the Modified Heat of Vaporization formula:

\[ \lambda = (h_{fg} + (c_{pv}) \times \frac{(T_w - T_{Sat})}{2}) \]

Where:

\( \lambda \) — Modified Heat of Vaporization (J/kg)
\( h_{fg} \) — Latent Heat of Vaporization (J/kg)
\( c_{pv} \) — Specific Heat of Water Vapor (J/kg·K)
\( T_w \) — Plate Surface Temperature (K)
\( T_{Sat} \) — Saturation Temperature (K)

Explanation: This formula modifies the standard latent heat of vaporization by accounting for the temperature difference between the plate surface and saturation temperature, weighted by the specific heat capacity of water vapor.

3. Importance of Modified Heat of Vaporization

Details: Accurate calculation of modified heat of vaporization is crucial for heat transfer analysis in boiling and condensation processes, particularly in industrial applications involving phase change heat transfer.

4. Using the Calculator

Tips: Enter all values in appropriate SI units. Latent heat and specific heat should be positive values. Temperature values must be in Kelvin and plate surface temperature should be greater than saturation temperature for meaningful results.

5. Frequently Asked Questions (FAQ)

Q1: Why modify the standard heat of vaporization?
A: The modification accounts for additional thermal effects when there's a temperature difference between the surface and saturation temperature, providing more accurate heat transfer calculations.

Q2: What are typical values for latent heat of vaporization?
A: For water at atmospheric pressure, latent heat of vaporization is approximately 2260 kJ/kg.

Q3: When is this modified formula particularly important?
A: This formula is especially important in boiling heat transfer applications where surface temperature differs significantly from saturation temperature.

Q4: Are there limitations to this equation?
A: The formula assumes linear approximation and may be less accurate for large temperature differences or in complex multi-phase flow situations.

Q5: Can this be used for substances other than water?
A: Yes, but appropriate values for latent heat and specific heat must be used for the specific substance being analyzed.