Deflected Water Jet Jets Of The Coal Seam Drilling

Pumping gas is one of the basic way to deal with gas. Usually, we need to drill a long hole in the coal bed for pumping gas. The routine of mechanical drilling skill is to cut coal, with the driving of circumvolving drill pipe to the aiguille. When the aiguille and the hole impinge on each other closely, the blocking, nipping and quick abrasion of drills can easily take place. If we employ the high pressure water jet skill to drill in the coal bed, we can avoid effectively the blocking, nipping and abrasion of drills, because the aiguille and the hole haven't impinged on each other in the process. Furthermore, if we employ the high pressure water jet skill, we can also extend the hole and its radius available. In China, the high pressure water jet skill is quite new. It is important to do research on jet aiguille and its character.Analyzing the foreign and domestic theories and skills of high pressure water jet, the author works out the gauche water jet aiguille for drilling in the coal bed, based on the specific analysis and illustration on the similarities, diffusibility and the speed attenuation of water jet submerged. Analyzing theoretically the rules of the movements of jet aiguille, the author works out the matching relations of all parameters, which influence the revolving speed of jet muzzle. Numerical simulation has been processedon the jet speed and the changing rules of pressure, according to standard k - ε double equation. The paper also dose research and illustration on the coal-breaking mechanism of high pressure water jet. The main results and conclusion are as follows:(1) With the theoretical analysis, the formula jet bounce-back force F = Qv_j isavailable.(2) Exercising Dynamic Law of Newton, we can figure out the numeric range of all factors which influences the rotate speed of muzzles: jet pressure (p) should be higherMp than , the value of leaning angle α must be bigger than, the value of circumvolving radius R should be bigger than...