Thermophysical Properties Databases: Temperature-Dependent k, ρ, cp, μ for Common Engineering Materials

Rock/Field Condition	Recommended Design Action
High-temperature gas cooling (T > 800 K, Re > 10⁵)	Use NIST Chemistry WebBook or JANAF tables for k(T), μ(T); avoid polynomial fits beyond 1200 K without validation
Liquid metal heat transfer (e.g., NaK, Pb-Bi) in nuclear systems	Apply OECD/NEA Thermophysical Properties Database (TPDB) with liquid-phase extrapolation limits ±50 K from measured range
Polymer processing (T near Tg, non-Newtonian behavior)	Combine DSC-derived cp(T) with rheometry-based μ(T,γ̇); use Carreau-Yasuda model instead of constant-viscosity assumption
Cryogenic fluids (LH₂, LCH₄ at < 120 K)	Prefer REFPROP v11+ with GERG-2008 EOS; validate against NIST Low-Temperature Thermophysical Properties Data Series

Rock/Field Condition

Recommended Design Action

High-temperature gas cooling (T > 800 K, Re > 10⁵)

Use NIST Chemistry WebBook or JANAF tables for k(T), μ(T); avoid polynomial fits beyond 1200 K without validation

Liquid metal heat transfer (e.g., NaK, Pb-Bi) in nuclear systems

Apply OECD/NEA Thermophysical Properties Database (TPDB) with liquid-phase extrapolation limits ±50 K from measured range

Polymer processing (T near Tg, non-Newtonian behavior)

Combine DSC-derived cp(T) with rheometry-based μ(T,γ̇); use Carreau-Yasuda model instead of constant-viscosity assumption

Cryogenic fluids (LH₂, LCH₄ at < 120 K)

Prefer REFPROP v11+ with GERG-2008 EOS; validate against NIST Low-Temperature Thermophysical Properties Data Series

📊 Key Properties & Parameters

k (Thermal Conductivity)

0.024–400 W/(m·K) — e.g., air at 300 K: 0.026, copper at 300 K: 401, stainless steel 304 at 500 K: 19.5

The ability of a material to conduct heat, defined as the rate of heat transfer per unit area per unit temperature gradient.

⚡ Engineering Impact:

Directly governs conduction-dominated heat flux magnitude and thermal gradients in heat sinks, reactor walls, and electronic packaging.

ρ (Density)

0.0012–19,300 kg/m³ — e.g., helium gas at 300 K: 0.178, water at 293 K: 998, tungsten at 298 K: 19,250

Mass per unit volume of a substance, varying with temperature due to thermal expansion or phase change.

⚡ Engineering Impact:

Determines inertial response in transient convection, buoyancy-driven flow strength (via ρβΔT), and structural mass loading in thermal systems.

cp (Specific Heat Capacity)

0.12–4.22 kJ/(kg·K) — e.g., lead at 300 K: 0.129, aluminum at 300 K: 0.897, liquid water at 298 K: 4.182

Amount of heat required to raise the temperature of unit mass of material by one Kelvin, reflecting its thermal inertia.

⚡ Engineering Impact:

Controls thermal time constant in transient heating/cooling; low cp amplifies temperature swings under cyclic loads (e.g., brake discs).

μ (Dynamic Viscosity)

0.000018–1.5 Pa·s — e.g., air at 300 K: 1.86×10⁻⁵, ethylene glycol at 298 K: 0.016, bitumen at 373 K: ~1.2

Measure of a fluid’s resistance to shear deformation, strongly dependent on temperature for liquids and gases.

⚡ Engineering Impact:

Dictates Reynolds number, pressure drop, pump sizing, and transition from laminar to turbulent flow in piping and heat exchangers.

📐 Key Formulas

Sutherland’s Law (Viscosity of Gases)

μ(T) = μ₀ × (T/T₀)^(3/2) × (T₀ + S)/(T + S)

Empirical correlation for dynamic viscosity of gases as function of absolute temperature

Variables:

Symbol	Name	Unit	Description
μ	dynamic viscosity	Pa·s	dynamic viscosity of the gas at temperature T
μ₀	reference dynamic viscosity	Pa·s	dynamic viscosity at reference temperature T₀
T	absolute temperature	K	temperature at which viscosity is evaluated
T₀	reference temperature	K	reference temperature corresponding to μ₀
S	Sutherland constant	K	empirical Sutherland constant specific to the gas

Typical Ranges:

Air between 200–1200 K

1.2×10⁻⁵ to 5.2×10⁻⁵ Pa·s

CO₂ between 300–800 K

1.5×10⁻⁵ to 3.1×10⁻⁵ Pa·s

⚠️ Valid only within ±15% of reference temperature T₀; avoid extrapolation beyond 2×T₀

Wiedemann-Franz Law (Metals)

k(T) = L × σ(T) × T

Relates thermal conductivity to electrical conductivity via Lorenz number L

Variables:

Symbol	Name	Unit	Description
k	Thermal conductivity	W/(m·K)	Material's ability to conduct heat
L	Lorenz number	W·Ω/K²	Universal constant relating thermal and electrical conductivity
σ	Electrical conductivity	S/m	Material's ability to conduct electric current
T	Absolute temperature	K	Temperature in Kelvin

Typical Ranges:

Pure Cu, 250–450 K

380–410 W/(m·K)

Stainless steel 316, 300–800 K

12–18 W/(m·K)

⚠️ Applies only to pure metals and dilute alloys; invalid for oxides, polymers, or semiconductors

🏭 Engineering Example

ITER Blanket First Wall Design (Cadarache, France)

Not applicable — material: EUROFER97 steel + Be armor + Li4SiO4 breeder

k (Be @ 500 K)

205 W/(m·K)

k (EUROFER97 @ 700 K)

24.3 W/(m·K)

cp (EUROFER97 @ 700 K)

0.52 kJ/(kg·K)

ρ (EUROFER97 @ 700 K)

7720 kg/m³

cp (Li4SiO4 solid @ 600 K)

1.18 kJ/(kg·K)

μ (Li4SiO4 melt @ 1100 K)

0.042 Pa·s

🏗️ Applications

Gas turbine blade cooling design

Nuclear reactor fuel cladding thermal stress analysis

Battery thermal management system (BTMS) simulation

Additive manufacturing (LPBF) melt pool modeling

🎨 Technical Diagrams

📚 References

📊 Key Properties & Parameters

k (Thermal Conductivity)

ρ (Density)

cp (Specific Heat Capacity)

μ (Dynamic Viscosity)

📐 Key Formulas

Sutherland’s Law (Viscosity of Gases)

Wiedemann-Franz Law (Metals)

🏭 Engineering Example

ITER Blanket First Wall Design (Cadarache, France)

🏗️ Applications

📋 Real Project Case

Air-Cooled Condenser Retrofit for 600 MW Coal Power Plant

🎨 Technical Diagrams

📚 References