Efficiency of fire suppression systems using dry powder sprays to extinguish fires amid non-steady heat exchange processes and heterogeneous inhibition of active flame centres by powder particles

. Presently, there are several problems in the eld of dry powder re suppression that require the indepth study of the physics and technology of re suppression processes using these substances. One of the ways to nd the solution to these problems is the efciency analysis (theoretical and experimental) of frequently implemented re extinguishing patterns involving re suppression systems spraying dry powder, when the term of interaction between the dry re extinguishing powder and the burning material is close to the duration of principal re extinguishing patterns, or thermal and heterogeneous inhibition of active ame centres. Purpose and objectives . The purpose of the work was to assess the efciency of principal re extinguishing patterns (thermal and heterogeneous inhibition of active ame centres) amid non-stable heat exchange processes and heterogeneous inhibition of active combustion product particles by powder particles. Methods . The pre-set objective was achieved through theoretical modeling of patterns of thermal re extinguishing and heterogeneous inhibition of active ame centres by dry chemical powder particles. Results . It was established that re suppression with the help of general purpose dry chemical powder under non-steady conditions is the more effective, the smaller the effective size of powder particles, the longer the time of their stay in the combustion area and the shorter the characteristic period of heat transfer to powder particles and heterogeneous inhibition of active ame centres. Conclusions . The results optimize conditions and patterns of dry re extinguishing powder application to a combustion area to achieve the highest extinguishing effect and to conduct a targeted search for new dry chemical powders having pre-set thermal and physical specications.