CALCULATION METHOD OF WATER CURTAIN SHIELDING PROPERTIES

This work represents generalization of earlier received results of simulation of water curtains used as fire protection walls. The central objective of the study is to characterize the interaction of the water spray with thermal radiation. Radiative properties for the droplets are calculated applying the geometrical optics approximation. Results of the analysis of the reference special cases formed a basis for receiving calculated formulae of common character. These formulae have been used to calculate transmittances of water curtains for thermal radiation of a near infrared range 1–10 6m. According to the received formulas, the transmittance of a water curtain depends on distribution of droplets by the sizes, specific water content, thickness of a curtain, spectral characteristics of a thermal radiation. Approximation functions which allow to avoid heavy operations of a numerical integration are applied to simplification of calculated formulae. The developed techniques allow to take into account parameters of a cumulative distribution function of droplets by the sizes and parameters of a radiation spectrum of the seat of fire. The complete set of calculated formulas received in the work allows to define an integral transmittance of a water curtain or to construct a transmission spectrum for the given initial parameters.