1. What is Excess Temperature in Boiling?

Excess Temperature in Heat Transfer is defined as the temperature difference between heat source and saturation temperature of the fluid. It represents the driving force for boiling heat transfer processes.

2. How Does the Calculator Work?

The calculator uses the Excess Temperature formula:

Where:

• \( T_{excess} \) — Excess Temperature in Heat Transfer (K)
• \( T_{surface} \) — Surface Temperature (K)
• \( T_{Sat} \) — Saturation Temperature (K)

Explanation: The equation calculates the temperature difference between a heated surface and the saturation temperature of the fluid, which drives the boiling heat transfer process.

3. Importance of Excess Temperature Calculation

Details: Accurate excess temperature calculation is crucial for designing efficient heat transfer systems, predicting boiling regimes, and preventing equipment failure in thermal engineering applications.

4. Using the Calculator

Tips: Enter surface temperature and saturation temperature in Kelvin. Both values must be positive numbers for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of excess temperature in boiling?
A: Excess temperature determines the boiling regime (nucleate, transition, or film boiling) and affects heat transfer coefficients in boiling processes.

Q2: What are typical excess temperature values for different boiling regimes?
A: Nucleate boiling typically occurs at 5-30°C excess temperature, transition boiling at 30-120°C, and film boiling above 120°C excess temperature.

Q3: How does excess temperature affect heat flux?
A: Heat flux initially increases with excess temperature in nucleate boiling, reaches a maximum at critical heat flux, then decreases in transition and film boiling regimes.

Q4: Are there limitations to this calculation?
A: The simple difference calculation assumes constant fluid properties and doesn't account for surface characteristics, pressure effects, or fluid composition variations.

Q5: Can this calculator be used for all fluids?
A: Yes, the basic formula applies to all fluids, but the practical implications of excess temperature vary significantly between different fluids and system pressures.