Calculate Viscosity at Given Temperature

Viscosity-Temperature Equation:

\[ \mu = \mu_{ref} \exp\left(-\frac{E_a}{R}\left(\frac{1}{T} - \frac{1}{T_{ref}}\right)\right) \]

Reference Viscosity (μ_ref):

Pa·s

Activation Energy (E_a):

J/mol

Temperature (T):

Reference Temperature (T_ref):

Calculated Viscosity (μ):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Viscosity-Temperature Equation?

The viscosity-temperature equation describes how the viscosity of a fluid changes with temperature. It's based on the Arrhenius relationship and is particularly useful for Newtonian fluids.

2. How Does the Calculator Work?

The calculator uses the viscosity-temperature equation:

\[ \mu = \mu_{ref} \exp\left(-\frac{E_a}{R}\left(\frac{1}{T} - \frac{1}{T_{ref}}\right)\right) \]

Where:

\( \mu \) — Viscosity at temperature T (Pa·s)
\( \mu_{ref} \) — Reference viscosity at T_ref (Pa·s)
\( E_a \) — Activation energy (J/mol)
\( R \) — Universal gas constant (8.314 J/mol·K)
\( T \) — Temperature (K)
\( T_{ref} \) — Reference temperature (K)

Explanation: The equation shows that viscosity decreases exponentially with increasing temperature, with the rate of decrease determined by the activation energy.

3. Importance of Viscosity Calculation

Details: Understanding how viscosity changes with temperature is crucial for designing fluid systems, lubrication applications, and industrial processes where temperature variations occur.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure temperatures are in Kelvin (K = °C + 273.15). The reference viscosity and activation energy should be known from experimental data or literature.

5. Frequently Asked Questions (FAQ)

Q1: What types of fluids does this equation apply to?
A: This equation works best for Newtonian fluids (constant viscosity regardless of shear rate) like water, oils, and simple organic liquids.

Q2: How accurate is this equation?
A: It provides good estimates for many fluids but may need modification for complex fluids or extreme temperature ranges.

Q3: Where can I find reference viscosity values?
A: Reference viscosities are typically available in material property databases, chemical handbooks, or from manufacturer specifications.

Q4: What if I only have Celsius temperatures?
A: Convert Celsius to Kelvin by adding 273.15 before entering the values (e.g., 25°C = 298.15K).

Q5: Can this be used for gases?
A: No, this equation is for liquids. Gas viscosity increases with temperature, following different relationships.