APPLICATION OF SUPERSONIC GAS JETS FOR ROCK DESTRUCTION

Abstract

This paper investigates in detail the aspects of supersonic gas jets application in the process of thermal destruction of rocks. The main attention is paid to various aspects of heat transfer, which is key in the use of such methods. The main thermodynamic parameters of a high intensity gas heat carrier in interaction with rocks are considered. Important characteristics are the heat transfer coefficient from the gas jet to the rock, the effective gas temperature at the rock surface and the specific heat flux. In order to achieve a more accurate mathematical description of the process of thermal destruction of rocks, the authors present a model of the interaction between the gas jet and the rock. They draw attention to the importance of the correct choice of geometric and thermal modeling parameters. Particular attention is paid to the stress-strain state of the rock under the influence of the gas jet heat flow, which is a key aspect in analyzing the efficiency of the fracture process. Various methods and parameters affecting the efficiency of heat exchange between the gas jet and the rock are also analyzed. An elastic half-space, which is a rock interacting with an external high-temperature medium, is considered. Heat exchange occurs according to the law of convection, and the maximum parameters of heat exchange from the jet to the rock are in 
the vicinity of the central point of its spreading at braking on the rock surface. The stress-strain state of the rock under the influence of the gas jet heat flow is investigated.