NON-STATIONARY TRANSMISSION OF HEAT AND HYGROSCOPIC MASS BETWEEN VENTIIATION FLOW OF METRO AND SURROUNDING MINING MASSIF

Print version was published: Mining Journal 1(140), 2018

According to modern technologies of construction and operation of transport tunnels, it is assumed in the present work that drainage of water does not occur inside the membrane in the area of reinforced coating of the tunnel and here takes place a non-stationary process  of transfer  of hygroscopic  mass  (moisture) together with а similar process of heat transfer between the ventilation stream and the surrounding mining massif. Thus, we have to deal only with the sorption mass content in the pores of the massif and the water in  the  explicit form in  the  tunnels  can  only be  in exceptional cases as local sources and therefore, their influence on the ventilation flow should be considered separately. The paper provides results of mathematical modeling of heat and mass transfer processes as well as  graphs  and  nomograms,  which  can  be  used  to define non-stationary coefficients of the heat and mass transmission required for thermal physics calculation of  underground  ventilation.  The  additional  flows initiated  by  the  Soret  and  Dufour  effects  usually strengthen the main flows, but in practice one can find a case where it is not necessary to take into account the effect of additional flows. Based on the analysis of processes, the criteria that determine the numerical value  of these  show  the  case when  accounting for additional flows of Soret and Dufour is mandatory. The marked effects can be ignored when 10⁶ Lα=1.