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Stator ventilation duct

QuickField simulation example

The air passes through the stator ventilation duct.

Problem Type
Axisymmetric problem of heat transfer.

Geometry
Stator ventilation duct The air passes through the stator ventilation duct q q Air flow D L Pipe

D = 30 mm, L = 4000 mm.

Given
Air speed in the duct v = 10 m/s,
Duct surface convection coefficient α = 50 W/K-m²,
Pipe thermal load q = 300 W/m².

Task
Determine the air temperature rise along the pipe.

Solution
The pipe is divided into n sections. The heat flux q from each section is calculated. The consumed energy dQ can be found as:

dQ = q·t, where
q - thermal flux (W),
t - duration of air passage through the section, t = (L / n) / v.

Then the air temperature rise is calculated as:

dT = dQ / (dV·C·ρ), where
dQ - consumed energy (J),
dV - volume (m³),
C - thermal capacity of air (J / kg·K),
ρ - density of air (kg/m³).

Results
Initial state: air temperature 0°C, thermal flux from the wall to the air q = 18.85 W (per one section), consumed energy dQ = 0.754 J, temperature rize per one section dT = 2.4 °C.

After 3 iterations air temperature rise along the channel is dT = 21.81 °C
ventilation duct heat flux

* Reference: John H. Lienhard IV, John H. Lienhard V, A heat transfer textbook.