In the dissertation work on the basis of generalized results of the theoretical and experimental studies performed, a new solution of the actual scientific and practical problem of increasing the level of environmental safety in blasting operations in quarries by suppressing a dust and gas cloud with the use of vapor-water-air reactive jets is presented.
The analysis of modern studies on environmental pollution during blasting operations in quarries and enhancement of environmental safety in the conduct of open mining operations is carried out. The estimation of existing methods of calculation of harmful emissions into the atmosphere, methods and means of combating dust and gas cloud during blasting operations in quarries is given. Despite the large amount of developed methods and means to combat the dust and gas cloud, there has been no significant increase in environmental safety in quarries. It is noted that the methods for estimating the parameters of the dust and gas cloud differ in complexity and do not allow calculating the parameters of the cloud during the period from 0 to 0,5 s.
The process of nucleation and formation of a dust and gas cloud during mass explosions in quarries with the use of high-speed filming and computer analysis of snippet is investigated. It has been established that during the period of the cloud initiation in the time interval 0,05-0,5 s it has small dimensions and can be neutralized by using active methods of dust and gas suppression, including exposure to the thermal and dust-gas center of the vapor-water-air reactive jets and refrigerants. The experimental dependences of the change in the height and rate of rise of the dust and gas cloud in the atmosphere of the quarry during the period 0,05-0,5 s are established for explosions of charges with a mass of 10-160 tons that allow one to estimate the dynamics of the change in the rate of rise of the cloud in comparison with the speed of vapor-water-air reactive jets during the simulation of their interaction.
A methodology is proposed for calculating vapor-water-air reactive jets in quarries, which are modeled as a plane and axisymmetric jet, which allows to determine the parameters of velocity, temperature, impurity concentration, transverse size and range at the initial, transitional and main station of the jets, and also evaluate the effectiveness of their use for dust and gas suppression.
Experimental studies of the aerodynamic parameters of the steam-water-gas-air jet on the example of the aircraft engine VK-1A have been carried out. The velocity, temperature, range, diameter and the angle of the jet opening have been determined, which made it possible to offer technical solutions for active dust and gas suppression in blasting operations in quarries.
A mathematical model of the process of interaction between a dust and gas cloud with a vapor-water-air reactive jets is developed. It is implemented as a package of application programs "CLOUD-2", which illustrates the principle of cloud suppression under the influence of a jet and the ability to reduce air pollution outside the quarry. It is shown that the efficiency factor of suppression of the dust and gas cloud reaches 96-97%.
A new method for suppressing the dust and gas cloud and an installation for its implementation that allow active dust and gas suppression of the thermal and dust center of the cloud during its nucleation during a period of 0,05-0,5 s are developed, which reduces the height of the dust and gas emission and prevents its spread beyond the quarry.
Key words: ecological safety, quarry, blasting, dust and gas cloud, air pollution, hydro-dusting, vapor-water-air reactive jets, mathematical model.
