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Summary: Knowledge about the heat release rate (HRR) is essential for studying tunnel fires. The standard method in ISO 9705 is widely applied to calculate the HRR of combustion by measuring the consumption of oxygen in a fire. However, the studies of HRR measurement in full‐scale tunnel fires are rare because of the complication and costs of large experiments. This paper presents a system based on the principle of oxygen consumption calorimetry for the measurement of HRR and total heat release (THR) of full‐scale fires in tunnels. A total of 22 fire experiments are performed in a large‐scale ventilated testing metro tunnel with dimension of 100.0 m × 5.5 m × 5.5 m to validate the reliability and effectiveness of this system. Firstly, four oil spray fire tests are conducted with nozzle flow of 106 L/h at (1 ± 0.1) MW HRR to calibrate the instrumentation. Then, 18 full‐scale fire tests using square diesel pools at five sizes (0.5, 1.0, 2.5, and 5.0 m2) and wood cribs as fire sources are carried out for the measurement of HRR and THR. Results provided by the comparison between the measured HRR and THR values of the fire tests and the theoretically calculated ones show that our system works effectively in the HRR measurement of full‐scale fires in tunnels. [ABSTRACT FROM AUTHOR]

A numerical study of oil pool fire with different cylindrical obstacles in a ship engine room was carried out. The characteristics of flame height, maximal temperature rise, and centerline axial velocity of fire plume were investigated and analyzed. The results showed that the flame height of the merged flame decreases with the increased radius ratio and obstacle height, while the plume maximal temperature rise and axial velocity decreases with a larger radius ratio. Under the broken flames, the flame height only decreases with a larger radius ratio, while the plume temperature rise and axial velocity decreases with the increase of both radius ratio and obstacle height. When the obstacle is smaller, the annular flames merge above the obstacle, while the annular broken flames surround the cylindrical obstacle when the obstacle is larger. And there is a competition between flame height enhancement effect and weakening impact when the flame could merge above obstacle. The empirical models of flame height, centerline temperature rise and axial velocity of annular pool fire with different cylindrical obstacles are obtained and validated by experimental test data. These results can offer an essential reference for fire prevention design and fire science research in the ship engine room. • Fire plume features of annular pool fire with obstacles are numerically studied. • Flame height declines with larger r/R and obstacle height under merged flame. • Temperature declines with larger r/R and obstacle height under broken flame. • Influence of cylinder obstacle on fire plume is determined by its size and height. • Empirical models of annular pool fire plume with cylinder obstacles are obtained. [ABSTRACT FROM AUTHOR]

Electric vehicle (EV) fires resulting from the thermal instability of high-energy lithium-ion batteries (LIBs) have become a significant hazard to public safety. Effective and prompt fire-fighting methods for dealing with EV fires are required. A fire protection method referred to as electric vehicle fire enclosure (EVFE) was proposed in this paper based on EV fire characteristics. Full-scale fire experiments were employed to evaluate the fire extinguishing efficiency of various types of EVFE. Results showed that EVFE could effectively suppress the thermal runaway (TR) of full-size LIB packs in the EVs under these experimental conditions, and the battery packs did not occur re-thermal runaway after EVFE stopped working. The agent consumption of water EVFE was 0.628 m3/kWh, while that of foam EVFE was 0.743 m3/kWh. Moreover, the overheated battery packs had an interesting TR propagation mechanism that TR discretely spread among the cells. The TR critical temperature of unconnected battery modules was not suitable for illustrating the TR characteristics of circuit-connection battery modules. For the full-size LIB packs, the TR onset temperature ranged from 31.8 °C to 117.3 °C. These results provide an insight into the fire protection methods and TR characteristics of the LIB packs in EVs. • A new fire protection method for dealing with electric vehicle fires is proposed. • The fire extinguishing performance of the method is evaluated by full-scale fire tests. • An interesting thermal runaway propagation mechanism is found in full-size lithium-ion battery packs. • The thermal runaway onset temperature of cells in the battery packs is between 31.8 °C and 117.3 °C. [ABSTRACT FROM AUTHOR]