Yong Ming Zhang

Experimental Study of Suppressing Vertical PS Fires Using Water Spray

Water suppression experiments of EPS and XPS are conducted in Standard Combustion Chamber in USTC in Hefei. The 20 cm * 20 cm PSs were held against a 600 mm*600 mm vertical gypsum board fixed by a steel frame structures to simulate a building facade. A series of results have been obtained. When the water spray is not applied, the EPS is easier to melt, drip and pyrolyze than XPS under the same fire load, but causes less amount of CO than the amount of XPS without any water application. When the water is applied, neither EPS nor XPS has a trend to drip. The amount of CO caused by EPS or XPS under water spray is much less than that of non-spray. Also the extinguishment time falls fast once the PS materials are applied with water. In addition, these experimental results demonstrate the feasibility of the designed rig in studying the fire suppression on vertical PS materials using water spray.

Ground-Based Study on Distribution of Fire Parameters and Installation of Fire Detectors in Space-Confined Microgravity

The manned spacecraft is a typically confined space in microgravity and it suffers severe fire risks. This paper studies on the distribution of the fire parameters in space-confined microgravity to find a more rational way to install the fire detectors. The experiments are carried out in the ground simulation experiment platform for fire based on the International Space Station. Based on the functional simulation principle, this paper maintains Gr (Grashof number) and increases Re (Reynolds number) to simulate microgravity environment in such a full-scale platform. The results show that Fire Detector 5 on the center of the side wall and Fire Detector 7 on the corner of the ceiling are the best installing locations for smoke detection. And, temperature detection is not appropriate in manned spacecraft. Namely, the way to install the fire detectors in manned spacecraft should be different from that in normal gravity.

Wireless Warning System of Positive Pressure SCBA Based on GPRS

Ordinary positive pressure breathing apparatus only supply the air to firefighters within a certain time, and cannot help to realize the real-time control of the service status of the apparatus, leading to the existence of security risks. In this study, a wireless early warning system of positive pressure breathing apparatus was proposed in response to the actual demand of the fire force based on a combination of GPRS communication technologies, intelligent prediction algorithm of the breathing apparatus, and network-based programming technologies. The system features strong applicability and small error (a working error of ±6%), and thus can satisfy the demand of enhancing the safety guarantee for firefighters on the fire-fighting and rescue scene and is of significant application value.

Early Image Fire-Detection Based on Maximum Margin Criterion

Nowadays as camera is applied widely, image fire detection becomes much popular. Many researchers are committed to analyze the RGB color model or even gray images. Actually they have some disadvantages. So this paper will present a new model based on Maximum Margin Criterion, a feature extraction criterion. As it is maximizing the difference of between-class scatter matrices and within-class scatter matrices, it does not depend on the nonsingularity of the within-class scatter matrix. First we will introduce the main idea and then give a mathematical description to apply the model to fire detection, with the algorithm we can calculate the result we need. At last we will put them into practice, use a database to do some experiments to present the performance of this method.

An Experimental Study on the Particle Concentration and Size Distribution of Smoke Generated by Flaming N-Heptane

The particles of smoke generated by flaming n-heptane was measured by Fast Particulate Spectrometer (DMS500), and the particle number concentration and size distribution were recorded and analyzed for investigating the smoke dynamic characteristics. The experimental results indicated that the particle number concentrations of buoyant plume above the flame approximately decrease with the height. At the center of ceiling, there is an approximate linear relationship between the particle number concentration and heat release rate. The count median diameter (CMD) varies with time and the change rate of CMD varies with particle concentration. In these experiments, the CMD is a constant in a few minutes after burning extinction.

Effects of Environment Temperature and Humidity on Size Distribution of Smolder Microparticles

The smoke particle size distribution of cotton rope smoldering fire were measured with DMS500 Fast Particulate Spectrometer under different temperature and humidity. Through the experiments, we prove that the temperature and humidity of environment have a great influence on cotton rope smoldering smoke particle size distribution. Cotton rope smoldering smoke particle size distribution at an elevated temperature will migrate to small size. Nevertheless, the effect of humidity is more complicated that need a more depth research. Additionally, Fire smoke aerosol is a non-steady-state.

Feasibility Analysis of a Method for Physical Source Apportionment of PM2.5 Based on Particle Morphology and Size Distribution

Inhalable particles do harm to the environment and health, especially fine particles, also as PM2.5. PM2.5 is the key pollutant of the compound air pollution, and becomes the primary indicator of the urban air pollution. Source apportionment to track the source of the particulate matter is important to the evaluation of the effect of pollution sources on environment and health. It can also provide scientific evidence for the prevention and control of air pollution. Methods of chemical source apportionment have been accurate and developed based on the assumption of linear combination of receptor model with much mathematical computing and complex operations. The physical characteristics such as morphology and size distribution of particulates from different sources are significantly different. We could establish data base of physical properties about atmospheric particulates, and develop a new physical method of source apportionment used in quantitative analysis.