Mixing Fluids Properties Calculator | Final Temperature of Mixed Liquids

Mixing Fluids Temperature Calculator

Calculate the final equilibrium temperature and total mass when mixing two fluids at different temperatures. Ideal for batch blending, tank mixing, and process temperature control.

🧪 Mixing Fluids Calculator

When two fluids at different temperatures are mixed adiabatically (without heat loss to surroundings), they reach a final equilibrium temperature determined by the conservation of energy. This calculator uses the weighted heat capacity method to compute the final temperature and total mass.

Fluid A
m₁, T₁, Cp₁

Fluid B
m₂, T₂, Cp₂

→

Mixture
T_final, m_total

Energy Balance (adiabatic mixing):
m₁·Cp₁·T₁ + m₂·Cp₂·T₂ = (m₁·Cp₁ + m₂·Cp₂)·T_final

Final Temperature:
T_final = (m₁·Cp₁·T₁ + m₂·Cp₂·T₂) / (m₁·Cp₁ + m₂·Cp₂)

Total Mass:
m_total = m₁ + m₂

Enter Fluid Properties

Fluid A — Mass (m₁) kg or lb

Fluid A — Specific Heat (Cp₁) kJ/(kg·K) or Btu/(lb·°F)

Fluid A — Temperature (T₁) °C or °F

Fluid B — Mass (m₂) kg or lb

Fluid B — Specific Heat (Cp₂) kJ/(kg·K) or Btu/(lb·°F)

Fluid B — Temperature (T₂) °C or °F

📊 Mixing Results

Final Temperature—

Total Mass—

Heat Lost by Hot Fluid—

Heat Gained by Cold Fluid—

Principles of Adiabatic Mixing

When two fluids are mixed in an insulated vessel (no heat exchange with the environment), the total thermal energy is conserved. The hot fluid loses heat and the cold fluid gains heat until thermal equilibrium is reached.

Energy conservation: Q_lost by hot fluid = Q_gained by cold fluid
Mass conservation: m_total = m₁ + m₂
The final temperature is always between T₁ and T₂
If both fluids have the same Cp, the result simplifies to a mass-weighted average temperature

Typical Specific Heat Values

Fluid	Cp (kJ/kg·K)	Cp (Btu/lb·°F)
Water (20°C)	4.18	1.00
Ethylene Glycol	2.34	0.56
Engine Oil	1.90	0.45
Ethanol	2.44	0.58
Methanol	2.53	0.60
Sulfuric Acid (98%)	1.38	0.33
Mercury	0.14	0.033

Frequently Asked Questions

Does this calculator account for heat of mixing?

No. This calculator assumes ideal mixing with no heat of solution or reaction. For systems with significant heat of mixing (e.g., acid + water, NaOH + water), the exothermic or endothermic effect must be added separately.

Can I use volume instead of mass?

You can use volume if you first convert to mass using density: m = ρ × V. Be careful with units — ensure density and volume are consistent (e.g., kg/m³ × m³ = kg).

What if phase change occurs during mixing?

This calculator assumes no phase change (both fluids remain liquid). If ice melts or steam condenses during mixing, latent heat must be included in the energy balance.

How accurate is this for real industrial mixing?

For well-insulated tanks with good agitation, this calculation is typically within 1–2°C of the actual result. Heat losses to the environment, incomplete mixing, and temperature stratification can introduce small errors.