1. What is the Andrade Equation?

The Andrade equation describes how the viscosity of liquids changes with temperature. It's particularly useful for water and other simple liquids, showing an exponential relationship between viscosity and inverse temperature.

2. How Does the Calculator Work?

The calculator uses the Andrade equation:

Where:

• \( \mu \) — Dynamic viscosity (Pa·s)
• \( A \) — Pre-exponential factor (2.414 × 10⁻⁵ Pa·s for water)
• \( B \) — Andrade constant (247.8 K for water)
• \( C \) — Temperature offset (140 K for water)
• \( T \) — Absolute temperature (K)

Explanation: The equation shows viscosity decreases exponentially with increasing temperature, as molecular interactions weaken at higher temperatures.

3. Importance of Viscosity Calculation

Details: Viscosity is crucial in fluid dynamics, chemical engineering, and materials science. It affects flow rates, heat transfer, and mixing efficiency in industrial processes.

4. Using the Calculator

Tips: Enter temperature in Kelvin, and the constants A, B, and C. Default values are for water. Temperature must be greater than constant C.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for A, B, and C?
A: For water: A=2.414×10⁻⁵ Pa·s, B=247.8 K, C=140 K. Other liquids have different constants.

Q2: What temperature range is valid?
A: The equation works best near room temperature. For water, 0-100°C (273-373 K) is typical.

Q3: Why does viscosity decrease with temperature?
A: Higher temperatures increase molecular kinetic energy, reducing intermolecular forces that resist flow.

Q4: Can this be used for all liquids?
A: It works best for simple, Newtonian liquids. Complex fluids may require different models.

Q5: How accurate is this equation?
A: For water, it's accurate to about 1% in the 0-100°C range. Accuracy varies for other liquids.