DETECTION OF THE DEPENDENCE OF WIND INFLUENCE ON THE CRITICAL SURFACE DENSITY OF HEAT FLOW

Abstract

The environment and its parameters depend on heat transfer processes and objects and have an unconditional impact on human activities.  The study of these factors and the ability to reduce their negative impact is an important issue today.  In the specified article the substantiation of dependence of wind influence on the minimum value of surface density of a heat stream at which there is a steady flame combustion by means of full factor experiment is carried out.  The authors determined the largest and smallest indicators of significant factors influencing the value of the critical surface heat flux density, namely wind speed (v, m / s) and the set surface heat flux density (q, kW / m²).

In the course of the research, a mathematical model was built which describes the dependence of wind influence on the critical surface heat flux density.  This dependence is presented as linear.  The corresponding constants for the numerical regression equation, which has the form of a linear one, are determined.  To determine the constants of the numerical regression equation, 4 numerical experiments were performed according to the matrix for planning a complete factorial experiment.  Due to the constructed regression dependence, a corresponding dependence surface was developed between the wind speed, the critical surface heat flux density and the time during which the material ignites.  Based on the results of the calculations, an appropriate table was developed for the values ​​of the critical surface heat flux density for substances and materials depending on wind exposure.  These tables can be used in the future to develop an improved simplified method for predicting the thermal impact of fire on adjacent construction sites, taking into account the impact of wind.