Influence of the radiative heat exchanges between the fire front and vehicle passengers in a road

Abstract

The influence of the radiative heat exchanges between the fire front and vehicle passengers’ in a road is made in this study. Numerical software, that simulates the vehicle thermal behaviour with complex topology and the human thermal response, in transient conditions, is developed and used. The numerical model that simulates the vehicle thermal behaviour and the passenger thermal response is based in energy and mass balance integral equations and works in transient conditions. These equations, solved by the Runge-Kutta-Felberg method with error control, are based in conduction, convection and radiation phenomena. All coefficients used in these equations are evaluated by a sub-model that calculates the internal and external view factors, radiative heat exchanges, glass radiative properties, occupation cycle, ventilation strategy, human thermo-physiology and heat and mass transfer coefficients by convection using empirical expressions. In the numerical simulation a bus, that runs in a road nearby a fire front, occupied with 52 passengers is used. The radiative heat exchanges numerical model between the fire front and the vehicle and between the vehicle and the passengers, based in Mean Radiant Temperature method, is used. The work is divided in three parts: the bus geometry, the passenger geometry and the fire front geometry (1), the view factor inside the and outside the bus passenger compartment (2) and the Mean Radiant Temperature that each bus bodies and human body section are subject (3).