Jie Ji

• Professor
• Managing Director at State Key Laboratory of Fire Science, University of Science and Technology of China

Background Asynchronous observations refer to observations that are obtained at multiple moments. The observation moments of fire fronts may differ throughout an entire wildfire area. Asynchronous observations include historical data, which hinders the effectiveness of data assimilation due to the lack of timely updates on changing fire fronts. Ai...

This paper is aimed at studying the down-reaching flame behaviors of tank fires with large ullage heights. Experiments were first conducted using a gas burner in a transparent quartz glass cylinder to simulate the large ullage and the experimental data was used to validate the computational fluid dynamics (CFD) model. Subsequently the effects of ul...

At present, there are few fire risk assessment models for historical buildings with wooden components that are highly vulnerable to fires. Bayesian network (BN) is a practical risk assessment method that is helpful to risk management. Because many indicators affect the fire risk of historical buildings, the BN may have many nodes and a complex stru...

This paper conducted an experiment to study the burn-through behavior of vertical wood boards of different thicknesses with one surface heated by fire. The board thicknesses were 1, 1.5, and 2 cm, and the burner powers were 5, 10, and 15 kW to simulate the early stage of fire. The results show that burn-through is caused by the continuous charring...

In the case of immersed tunnel fires, lateral smoke extraction is a method employed to control the smoke movement with vents set in tunnel sidewalls due to limited space in height. This paper has investigated the smoke extraction efficiency of multiple lateral vents system using large eddy simulations (LES) in a fire dynamics simulator (FDS). The a...

Wildland fire extent varies seasonally and interannually in response to climatic and landscape-level drivers, yet predicting wildfires remains a challenge. Existing linear models that characterize climate and wildland fire relationships fail to account for non-stationary and non-linear associations, thus limiting prediction accuracy. To account for...

In situ burning is a widely used method in oil spill cleanup. This paper aims to study the burning behavior of n-heptane in ice cavities with aspect ratios ranging from 1 to 10. The depth and opening area of ice cavities were 9 cm and about 100 cm², respectively, for all cases before ignition. Results show that the dynamic variation process of burn...

In this study, arabinose was selected as the model compound of hemicellulose. The pyrolysis experiments were conducted by combined thermogravimetry-Fourier infrared spectroscopy-gas chromatography-mass spectrometry (TG-FTIR-GC–MS) technique. The evolution of functional groups was observed. Experimental results indicated that the main gas products w...

Actual chemical industrial park accidents usually involve multi-hazard accidents. Synergistic effect of accidents could lead to serious casualties. In order to reduce the individual risk of accidents, this work proposes a method for managing the dynamic individual risk when toxic substance leakage and fire accidents occur concurrently, in which spa...

This paper presents an experimental and theoretical research on the double-sided concurrent flame spread behavior of inclined planks. Pine log planks with a size of 100 cm long, 30 cm wide and 1 cm thick were used with six angles of inclination (θ). Results showed that the flame and the pyrolysis front on the upper surface present an inverted "V" s...

This paper has analyzed the phenomenon of plug-holing under lateral mechanical exhaust in tunnel fires by conducting large eddy simulations (LES) with Fire Dynamics Simulator (FDS). The lateral mechanical smoke exhaust is a method of smoke controlling in tunnel fires with exhaust vents set in the tunnel sidewall. The results show that the phenomeno...

This paper presents an experimental study on downstream radiative heat flux and temperature rise distribution of tunnel fires under the combined effects of longitudinal wind and sidewall restriction. Two fire locations, i.e., centerline fire and sidewall fire, were considered, and the wind speed were varied between 0-3 m/s. The results show that un...

This work aims to interpret the flame interaction mechanisms of the mass burning rates of two pool fires in a cross-airflow. The flame morphology, mass burning rate, and heat feedback components are measured. The results show that the mass burning rates of the two pool fires increase rapidly, then decrease, and finally increase slowly with wind spe...

In the process of production, transportation and storage of liquid fuel, accidental leaked liquid fuel could cause the flame spread, which may eventually lead to a serious fire accident. Therefore, it is imperative to study the characteristics of flame spread. Experiments of flame spread was conducted with eight-size pools whose width ranges from 4...

Timbers of the buildings are commonly covered with coatings to increase the fire retardancy. Compared with the current flame retardant coating, the traditional coating used in Chinese heritage buildings is much thicker and mainly acts as the thermal barrier plate. However, this kind of coatings could easily crack and flak affected by the environmen...

This paper investigated the spill flame behavior and temperature distribution for the compartment with two opposing openings under the effect of sideward wind. The experiment was carried out in a reduced-scale cubic compartment with two opposing openings (window and door). The sideward wind speed ranges from 0 to 4 m/s. The experimental results sho...

In general, the allocation strategy of safety measures in the domino effect is based on technical standards or simplistic rules of thumb, often leading to a subjective and uncertain decision-making process. In this work, a cost-effective risk reduction optimization model is proposed to objectively allocate the safety investment concerning domino ef...

Data mining (DM) has been applied in many advanced science and technology fields, but it has still not been used for domino effect risk management to explore minimum risk scenarios. This work investigates the feasibility of DM in minimizing the risk of fire‐induced domino effects in chemical processing facilities. Based on DM, an evidential failure...

The current research on individual risks mainly focuses on the individual risk considering a single fire or the spatial distribution of multiple fires. It is more realistic to study spatial and temporal variations of individual risks. Based on the probit model, an improved approach is presented to assess the spatial and temporal variations of indiv...

A feature of Chinese historical buildings is the preservation of many traditional customs, such as using candles and incense burners, and decorating the rooms with some textiles. Therefore, there are both many fire sources and combustible materials indoors, which puts a huge threat to fire safety. Although some researchers have experimentally studi...

Jet fire usually appears in natural gas fuel production and transportation due to uncontrolled fuel leakage. Jet fire can impinge on equipment surface or a passive firewall to make the fire plume temperature and the radiant heat flux complex. Experiments of a horizontal jet flame impinging a wall under various fuel initial velocity and nozzle-wall...

Prediction of building fire smoke spread behaviors plays an important role in the evacuation in an emergency to mitigate fire risk. Based on data assimilation, a cost‐effective approach was proposed to predict fire smoke spread behaviors under unknown mixed disturbances by combining a zone model (CFAST) and Ensemble Kalman Filter (EnKF). CFAST is u...

In actual fire, a solid wall is commonly established using nearby noncombustible solid materials to resist flame propagation. However, there are always some narrow channels owing to uneven surface of solid materials. There are inherent differences between liquid flame spread in narrow channels and infinite width fuel, including dynamic shear and he...

A self-developed laboratory-sized spilling trench is used to study the characteristics of continuously spilling fire spread over n-butanol fuel under different slope angles (0°, 1°, 2°, 3°, 4°) and discharge rates (0 - 500 mL/min). The hydrodynamic analysis is conducted to account for the variation of flow parameters of unburned liquid based on the...

The remote ignition and accelerated flame spread in multiple fires accidents are mainly due to the thermal radiation. The merged flame height and external radiative heat flux distribution of the square fire arrays were investigated numerically. Different burner spacing, total number of burners and heat release rate (HRR) of an individual burner wer...

Processing facilities are faced with spatial-temporal dependent multiple-hazards. These hazards could cause catastrophic consequences. A novel vulnerability model called the “fire and explosion synergistic effect model” (FESEM) is proposed in the present study to model equipment vulnerability under the spatial-temporal synergistic of heat radiation...

Timber is cost-effective and environmentally-friendly, which is a potential material for sustainable buildings, but its fire safety is still a significant concern. In this work, we investigate the burning behaviors of different types of woods and their self-extinction mechanism under external radiation. A unique near-limit flame is observed when th...

This paper investigates the effects of ullage height (distance between the fuel surface and the pool upper rim) on heat feedback and combustion emission mechanisms of heptane pool fires. Results showed that ullage height significantly influences the flame structure and fuel mass loss rate. The incident radiative heat flux to the fuel surface and it...

Risk assessment (RA) plays a vital role in safety engineering. The conventional RA approaches have limited capabilities in handling time dependence and data uncertainty. Although dynamic Bayesian network (DBN) is robust in inference under uncertainty due to its flexible structure and capability of modeling the interdependencies of variables, it sti...

Fires caused by fuel leakage pose serious hazards to the city’s environment and safety. Different leakage conditions will lead to different shapes of fire sources and produce different hazards to the surrounding environment. To study the characteristics of rectangular fires, this paper conducted experimental studies on rectangular burners with diff...

Pool fires are frequently reported to trigger domino effects in oil storage farms and chemical factories. Fire plume is the vehicle of damage caused by pool fires. This study aims to study the effects of ullage height (distance between the fuel surface and the upper pool rim) on fire plume flow and combustion characteristics were conducted by exper...

Multiple fires of unequal heat release rate (HRR) is a common fire scenario in real fire accidents. Differing from most previous research assumption of identical fire sources, the unequal HRR for those fire sources is regarded as more reasonable in reality. To explore the asymmetric flow characteristics surrounding multiple fires under such circums...

This paper is to quantify the external wind effects on flame behavior evolutions inside and outside a compartment with opposing openings. Temperature profiles at the windward and leeward corners inside the compartment as well as the external flame trajectories were investigated. Experimental results show that the flame shape inside the compartment...

Fire is a typical thermal runaway process of uncontrolled energy release. The possible ignition of adjacent leaked fuel might induce multiple fires burning simultaneously. A series of numerical simulations have been conducted to study the flame merging behavior and air entrainment restriction effect from square propane fire arrays. The simulation r...

Fuzzy Bayesian network (FBN) has been widely used for risk assessment of accidents in process industries to deal with complex causality and uncertainty arising from complex interdependence among risk factors, insufficient data and complex environments. The similarity aggregation method (SAM) is a method of aggregating fuzzy opinions considering con...

Investigation of wind-blown fires is highly applicable to fire safety of scenarios associated with burning industrial fuel tanks in wind and wildland fires. This paper conducts a numerical study on the flow characteristics around two propane fire sources in the tandem arrangement under cross wind. The heat release rate, cross wind velocity and fuel...

The production and transportation processes of gas fuel may be faced with a safety challenge in the form of a jet fire from pipeline leakage. In actual accidents, sometimes some obstacles may appear in the path of the horizontal jet fire development leading to impingement. The spread mechanism of such a flame is complex due to the coupling relation...

The interaction of multiple fires may lead to a higher flame height and more intense radiation flux than a single fire, which increases the possibility of flame spread and risks to the surroundings. Experiments were conducted using three burners with identical heat release rates (HRRs) and propane as the fuel at various spacings. The results show t...

This paper is a re-examination to quantify the flame tilt angle of fires induced by stack effect from a heat and mass transfer perspective. In previous studies, the critical transition and length of the deflection flame were formulated. In the current study, with different kinds of fuels, the flame tilt angles under different strength of stack effe...

This chapter aims to present an overview of advanced methods used in risk assessment and management of domino effects in the chemical process. This overview is mainly based on the materials that are mainly concerned with domino effects in chemical processes and available publicly. The research community has contributed numerous advanced methods for...

Due to complexities and uncertainties, risk management of domino effects in chemical plants in operation is challenging. A global optimal risk management scheme can hardly be obtained, therefore, finding a targeted local optimal risk management scheme can be prudent. In the present study, a novel risk management approach is proposed to reduce fire-...

Investigating the evolution of the fire plume centerline temperature has both fundamental and practical importance to process safety, risk analysis and disaster control. In practice, ullage height (distance between the fuel surface and the container upper rim) is a common boundary condition that affects the burning intensity and the flaming charact...

This paper has analyzed the asymmetric flow effect of fire-induced thermal flow in a horizontal tunnel under the natural ventilation condition by conducting large eddy simulations (LES). The key objective is to reveal and to have a better understanding of the asymmetric flow effect caused by the upstream and downstream tunnel length difference. The...

This study experimentally investigated the flame radiation characteristic of line pool fires in open space. The n-heptane line fires burning in the pools with different aspect ratios of length to width (n) were conducted. The mass loss rate (MLR), radiation distribution (along the flame plane), and radiant fraction are investigated by using wide-vi...

The combustion characteristics of blended fuels pool fire were experimentally studied. Six square pools with length ranging from 5 cm to 20 cm were adopted, and mutually insoluble n-heptane-methanol blended fuels were used with different mixing proportions. In the experiments, burning rate and fuel temperature were measured and recorded during the...

A fire-induced domino effect can be considered as a combination of an uncertain event and deterministic events, the occurrence of primary fire accidents can be considered as an uncertain event, and the occurrence of secondary fire accidents could be considered as deterministic events since accident escalation is controlled by fire heat radiation do...

This paper investigated the flame height and air entrainment of two adjacent buoyant turbulent jet non-premixed flames with the same base dimension whilst having different heat release rates (HRRs). Propane was used as fuel. The HRR of one of the burners was fixed at 8, 16, 24, 32 and 40 kW, respectively. By increasing the HRR of the other burner,...

The cotton fire often occurs during storage, and it is valuable to reveal the combustion characteristics of cotton bales. However, most of the previous studies only focused on the combustion phenomenon of cotton bales after ignited externally. In fact, during the storage of cotton, the fire often originated from inside of a cotton bale, resulted fr...

Flame merging is deemed to enhance the burning intensity and make the fire more destructive. This paper presents an experimental study on merging behaviors of two same rectangular heptane pool fires with long sides parallel. The pan aspect ratio was set 2–4 and the spacing was changed. The burning rate and flame height were measured. As the spacing...

Using a compartment with adjustable oxygen concentration and internal pressure, the shrinkage and cracking of isotropic char layer during pyrolysis were studied by pyrolyzing the medium density fibreboard (MDF) in inert atmosphere with different ambient pressures. The experimental results have shown that the ambient pressure has insignificant effec...

The low-temperature oxidation mechanism of n‑butyl radicals (n-C4H9) has been investigated by high level quantum chemical calculations coupled with the Rice–Ramsperger–Kassel–Marcus/Master Equation (RRKM/ME) theory. The potential energy surfaces (PES) were explored at the QCISD(T)/CBS//B3LYP/6-311++G(d,p) level. The temperature- and pressure-depend...

This paper aims to study the burning behaviors and heat feedback mechanisms of pair of unequal circular pool fires. A series of experiments on heptane pool fires with four diameters of 10, 15, 20 and 30 cm comprising 6 groups of unequal two pans was carried out. The pan edge spacing (S) was varied as a multiple of half of the diameter of the small...

This paper presents an experimental investigation on the flame radiation characteristics of pool fire, including the flame emissivity, diameter and temperature. A series of experiments of heptane pool fires with diameters of 0.1–0.4 m were carried out. The flame height, mass loss rate, temperature distribution, flame emissivity and radiative heat f...

Experimental investigations were carried out to estimate the radiative heating that occurs downstream of wind-driven buoyant turbulent diffusion flames produced by twin square propane burners aligned parallel to the cross wind. During the experiments, the heat release rate, cross wind velocity, and burner edge spacing were changed. Considering the...