🔥 Radiation in Participating Media (P1 Model)

Evaluate radiative heat flux in absorbing, emitting, and scattering semitransparent gray media using P1 differential spherical harmonics and Rosseland diffusion conductivity.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

📊 Solver Telemetry ● ACTIVE

👁️ Consultations 27

⚡ Calculs faits 22

💾 Téléchargements 140 📦 Code Fortran 5.4 KB

📅 Mise en service Jun 2026

⏱️ Latence < 1 ms

🔥 Participating Semitransparent Medium & Photon Scattering Field

Real-time visual simulation of photon emission, volumetric gas absorption & isotropic scattering attenuation

📝 Configuration & Presets

🥃 Glass Melting Furnace 🏭 Coal Boiler Flue Gas 🚀 Rocket Soot Plume 🧱 Porous Radiant Burner

📐 Geometry & Wall Temperatures

Medium Thickness L [m]:

Hot Wall Temperature T₁ [K]:

Cold Wall Temperature T₂ [K]:

🧪 Optical & Radiative Properties

Absorption Coeff a [1/m]:

Scattering Coeff σ_s [1/m]:

Hot Wall Emissivity ε₁:

Cold Wall Emissivity ε₂:

P1 Spherical Harmonics Formulation:
• Extinction Coeff: β = a + σ_s | Optical Thickness: τ₀ = β · L
• P1 Heat Flux: q_r = σ (T₁⁴ − T₂⁴) / [ (1/ε₁ − ½) + (1/ε₂ − ½) + ¾ τ₀ ]
• Rosseland Diffusion: k_rad = 16 σ T_mean³ / (3 β) [W/(m·K)]
• Scattering Albedo: ω = σ_s / β

📊 Radiative Flux Results

📊 Output Summary
💾 Fortran Source

P1 Radiative Heat Flux (q_r)

q_r = 31.12 kW/m²

Transparent Limit: 138.47 kW/m² | Attenuation: 77.5 %

τ₀ = 6.90

Optical Thickness (τ₀) 6.90 Optically Thick

Rosseland Conductivity (k_rad) 141.60 W/(m·K) Equivalent Diffusion

Scattering Albedo (ω) 0.652 Extinction β = 2.30 m⁻¹

Rosseland Diffusion Flux 35.40 kW/m² Thick medium limit

📈 P1 Heat Flux q_r (kW/m²) vs Optical Thickness τ₀

📉 Radiative Heat Flux vs Hot Wall Temperature T₁ (K)

=================================================================
 THERMOFLUIDCALC — PARTICIPATING MEDIA RADIATION (P1 MODEL) REPORT
=================================================================
Case Title                 : Pulverized Coal Combustion Boiler Radiating Flue Gas
Medium Slab Thickness (L)  : 3.000 m
Wall Temperatures (T1 x T2): 1400.0 K (1126.8 C) x 650.0 K (376.9 C)
Optical Coefficients       : a = 0.80 m-1, sigma_s = 1.50 m-1 (Extinction beta = 2.30 m-1)
Wall Emissivities (e1 x e2): 0.80 x 0.80
-----------------------------------------------------------------
OPTICAL THICKNESS (tau_0)  : 6.9000
Scattering Albedo (omega)  : 0.6522
P1 RADIATIVE HEAT FLUX (qr): 31.118 kW/m2
Transparent Limit Flux     : 138.474 kW/m2
Rosseland Diffusion Flux   : 35.399 kW/m2
Rosseland Conductivity     : 141.597 W/(m.K)
=================================================================

📘 Calculation Methodology & P1 Spherical Harmonics Standards

P1 Differential Approximation

The P1 method expands the directional radiative intensity into spherical harmonics, converting the complex integro-differential RTE into an elliptic Helmholtz equation:

                    ∇²G − 3aβ G = −12aβ σ T⁴
                

Rosseland Diffusion Analogy

In optically thick media ($\tau_0 \ge 3$), radiation acts like pure non-linear heat conduction with equivalent radiative conductivity $k_{rad} = \frac{16\sigma T^3}{3\beta}$.

Key Engineering Assumptions

1D planar participating medium slab.
Gray gas with wavelength-independent absorption and isotropic scattering.
Opaque diffuse gray wall boundaries ($\epsilon_1, \epsilon_2$).

ThermoFluidCalc Engineering Report