Mathematical modeling of the gasdynamic charcteristics of the heat-transfer medium jet in a process of the thermal reaming of the borehole - O. I. Voloshyn; Yu. Potapchuk; O. V. Zhevzhyk; V. I. Yemelianenko; V. P. Teplyi; L. T. Kholyavchenko; S. V. Shniakin (Geo-Technical Mechanics, 2017)