💻 Microchannel Two-Phase Flow Boiling

Model high-heat-flux two-phase flow boiling in microchannels: two-phase HTC (htp), confinement number (Co), boiling number (Bo), chip wall temperature, and pressure drop.

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

Convection

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⚡ Solves 29

💾 Downloads 387 📦 Fortran Code 10.8 KB

📅 Released Jun 2026

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💻 Silicon Microchannel Cold Plate & Confined Vapor Slugs

Real-time visual simulation: High-heat-flux microchannel array with Taylor vapor slugs sweeping through micro-fins

📝 Configuration & Presets

🖥️ AI GPU Chip (R1233zd) ⚡ EV SiC Inverter (Water) 📡 Radar GaN RF Power ❄️ Micro-Evaporator Loop

📐 Microchannel Array Dimensions

Channel Width w_c [mm]:

Channel Height h_c [mm]:

Channel Length L [mm]:

Number of Channels N_ch:

⚡ Operating Hydraulics & Heat Flux

Mass Flux G [kg/(m²·s)]:

Base Heat Flux q″ [W/cm²]: 1 W/cm² = 10 kW/m²

Mean Vapor Quality x (0.05 - 0.9):

Saturation Pressure P_sat [bar]:

🧪 Fluid Thermophysical Properties

Liquid Density ρ_L [kg/m³]:

Vapor Density ρ_V [kg/m³]:

Latent Heat h_fg [kJ/kg]:

Surface Tension σ [N/m]:

Kandlikar Microchannel Formulation:
• Confinement Number: Co = (1/D_h) √(σ / (g (ρ_L − ρ_V))) > 0.5
• Boiling Number: Bo = q″ / (G · h_fg)
• Two-Phase HTC: h_tp = max( h_NBD, h_CBD ) [W/(m²·K)]
• Wall Temperature: T_wall = T_sat + (q″ / h_tp) [°C]

📊 Microchannel Boiling Results

📊 Output Summary
💾 Fortran Source

Two-Phase Boiling HTC (h_tp)

h_tp = 251,415 W/(m²·K)

Base Wall Temp: 59.4 °C (T_sat = 45.5 °C) | Heat: 630.0 W

Co = 3.96 (Microchannel)

Hydraulic Diameter (D_h) 0.225 mm Microchannel regime

Boiling Number (Bo) 1.30e-2 q″ / (G · h_fg)

Two-Phase Pressure Drop 17.69 kPa 0.177 bar

Liquid-Only HTC (h_LO) 4,960 W/(m²·K) Boiling enhancement = 50.7x

📈 Boiling HTC h_tp [W/(m²·K)] vs Vapor Quality x

📉 Two-Phase Pressure Drop ΔP (kPa) vs Mass Flux G

=================================================================
 THERMOFLUIDCALC — MICROCHANNEL FLOW BOILING (KANDLIKAR) REPORT
=================================================================
Case Title                 : Military Radar GaN RF Transmitter Extreme Heat Dissipator
Microchannel Array         : w = 0.15 mm, h = 0.45 mm, L = 15.0 mm (Dh = 0.225 mm, N = 80)
Operating Flow Conditions  : Mass Flux G = 1500.0 kg/(m2.s), Base Heat Flux q" = 350.0 W/cm2 (3500.0 kW/m2)
Thermodynamic State        : Vapor Quality x = 0.40, Saturation Pressure = 4.00 bar (Tsat = 45.5 C)
-----------------------------------------------------------------
CONFINEMENT NUMBER (Co)    : 3.957 [Confined Microchannel Flow]
BOILING NUMBER (Bo)        : 1.296e-2
TWO-PHASE BOILING HTC (htp): 251,415.0 W/(m2.K)
Liquid-Only Baseline HTC   : 4,960.2 W/(m2.K)
BASE WALL CHIP TEMPERATURE : 59.41 deg C (Overheat DeltaT = 13.92 C)
Two-Phase Pressure Drop    : 17.69 kPa (0.1769 bar)
Total Dissipated Heat Power: 630.00 W
=================================================================

📘 Calculation Methodology & Microchannel Boiling Standards

Kandlikar Microchannel Correlation

Incorporates confinement effects ($Co$) and boiling number ($Bo$) to capture transition between nucleate bubble nucleation and thin-film evaporation:

                    htp = max( hNBD, hCBD )
                

Confinement Number Criterion

When $Co = \frac{1}{D_h}\sqrt{\frac{\sigma}{g(\rho_L - \rho_V)}} > 0.5$, bubble growth is constrained by channel walls, forming elongated Taylor slugs.

Key Engineering Assumptions

Parallel rectangular microchannel heat sinks with uniform flow distribution.
Saturated two-phase flow boiling regimes ($0.05 \le x \le 0.85$).
Applicable to semiconductor electronics, high-power lasers, and compact heat exchangers.

ThermoFluidCalc Engineering Report