Fire Dynamics Tools | Ch. 2 | Eq. 2.7

Nondimensional Hot Gas Temperature Increase

Calculates the nondimensional hot gas temperature increase for naturally ventilated enclosures

Reference

Fire Dynamics Tools (FDTs): Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program. NUREG-1805.

Equations

\Delta T_g / T_a = 0.63 \cdot \left( \frac{\dot{Q}}{\dot{m} \cdot c_p \ T_a} \right)^{0.72} \cdot \left( \frac{h_k \cdot A_t}{\dot{m} \cdot c_p} \right)^{-0.36}

Inputs

Heat release rate ( \dot{Q} ) — kW

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Mass flow rate of gas ( \dot{m} ) — kg/s

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Ambient temperature ( T_a ) — K

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Heat transfer coefficient ( h_k ) — kW/(m^{2} \cdot K)

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Total interior surface area ( A_t ) — m^{2}

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Specific heat of gas ( c_p ) — kJ/(kg \cdot K)

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