Weng Wenguo

Evaluation of thermal safety in fire using human thermal model and CFD simulation

The fires bring huge loss every year, a large number of firefighters and victims are seriously injured in fires and many of them even lost their lives. The aim of this work is to study on the thermal safety and discomfort of human body in fire environment using modeling and CFD methods. A transient multi-node human thermal model is developed for improving the simulation of thermoregulation in serious condition. Coupled with the human thermal model, a real shaped model of male body with 176 curved surfaces and more than 200 thousand cells, and real physical parameters was built. The CFD computation was taken using standard k-epsilon turbulence viscous model and discrete coordinate radiation model. A virtual room with 3.0m × 3.0m × 2.6m was built and series of fire with typical heat release rate were introduced as heat resource. The simulation was taken with 0.5 second time step. The prediction of thermal injury degree was considered with Stolls and Takatas injury model based on data from model and CFD computation. The time for heat stroke, deeply injury and degrees of thermal comfort indices were compared, the prediction of thermal safety and discomfort was made. Furthermore, a ventilated, fire-resistant enclosure including a radiator is constructed to improve the experiment.

Review of Public Safety in Viewpoint of Complex Networks

In this paper, a brief review of public safety in viewpoint of complex networks is presented. Public safety incidents are divided into four categories: natural disasters, industry accidents, public health and social security, in which the complex network approaches and theories are need. We review how the complex network methods was developed and used in the studies of the three kinds of public safety incidents. The typical public safety incidents studied by the complex network methods in this paper are introduced, including the natural disaster chains, blackouts on electric power grids and epidemic spreading. Finally, we look ahead to the application prospects of the complex network theory on public safety.

A cellular automaton evacuation model based on mobile robot’s behaviors

The research of evacuation in some emergencies, e.g. fire, is of great benefit to reducing the injuries of persons. In this paper, a cellular automaton evacuation model based on mobile robot’s behaviors is presented. Each person is treated as an intelligent mobile robot, and motor schemas, including move-to-goal, avoid-obstacle, swirl-obstacle and nervous-motion, drive persons to interact with their environment. The motor schemas are combined with cellular automaton theory, and an evacuation model is built. Evacuation simulation of persons with different move velocities shows that the presented model can predict accurately the evacuation phenomena in some emergencies.

Study on the statistical properties of China's Railway Network

Chinas Railway Network with train and passenger flows is studied. The train network displays small-world properties: a large clustering coefficient (0.671315), a short average path length (2.36714), and exponentially decaying cumulative degree distributions. No significant assortative mixing is found. As for the passenger network, the distributions of the passenger flow, including weight of edges and strength of nodes, follow power law, indicating scale-free characteristics. The weighted clustering coefficient is smaller (0.371953). The joint distributions of the strength and the degree of nodes follow power law, showing strong correlation between the passenger flow and the train flow.

Assessment of Human Safety and Thermal Comfort in High‐Temperature Environment: CFD and Human Thermoregulation Model

The safety and the thermal comfort of victims and firefighters are important in the building fires, which are a little dependent on the occupant fatalities. In order to investigate the effects of the dangerous environment on human body in fires, numerical calculation of the heat transfer and human thermoregulation are presented in this paper. The numerical manikins coupled with human thermal models were proved as powerful tools for visualizing thermal comfort. The two‐node model by Gagge and multi‐code thermoregulation models were investigated, and the Gagge’s model was coupled with the CFD for high‐temperature environment simulation, with which a numerical manikin was built. During the simulation, temperatures of skin and core compartment of Computer Simulated Person (CPS) were recorded respectively, and the Predicted Mean Vote index values were counted. The thermal load on skin is much higher than neutral cases and the skin can be burnt in minutes if no protection and heat abstraction methods were intro...