Experimental Study On Key Technology Of Spray Foam Inside The Roadheader For Dust Suppression

Dust will be generated in coal mine construction and production process. With the improvement of mechanization and production, there is a sharp rise of dust concentration in roadleader working face. But spray dust aqueous medium is poor wet and the working environment is worse while ventilation dust removal system is complex and the volume noise big. Both of them have poor dust effect. The effect of traditional technology of foam dust is good, but the jet spread made a lower utilization rate of bubble and the cost is high. Submerged spray foam dust for cutting head of the roadleader is put forward on the basis of field investigation. The key technology of spray foam inside the roadheader for dust suppression is systematically studied by comprehensive methods such as field test, theoretical analysis, numerical simulation and experimental research.The mechanism of dust generated by roadleader rock breaking is analyzed from the macro and micro. The key technology of spray foam inside the roadheader for high efficient dust suppression is put forward by the study of dust suppression by foam, which is submerged spray foam dust suppression technology. In the cutting process foam can wet and stick the dense nuclear when it is in constraint state, and other foam which eject from the side can continue to wet the cutting down coal and rock. All foam would cover in the surface of coal and rock that can reduce dust generation from the source. Based on a large number of technology research of spray water inside roadheader and analysis of traditional technology for dust suppression by foam, we can find the technology consume very little water and produce an amount of low pressure foam. The technology would fundamentally overcome the problem that spray pipe seal is not reliable and solve the clogging problem by large diameter jet nozzle. However, the spray water pipe inside roadheader is very curve and narrow and the pressure loss is big. The traditional process can not add foaming agent normally and the pressure loss of spoiler foam generator is big. In addition, the foaming ability is weak, so the characteristics of high backpressure water jet suction and coupling mechanism of porous spiral foam generator is researched.High pressure water jet in low ratio of suction device is designed from the principle of jet pump. The relationship between the nozzle diameter, throat diameter, throat mouth distance, pipe length and flow ratio, head ratio, unit efficiency is theoretical analyzed through the analysis of the existing technology and experimental research. Influence between internal flow field characteristics and backpressure recovery capability of absorbing device by key dimensions is proved through numerical simulation and experiments verify them. Gas-liquid mixed porous spiral foam generator is designed to improve the foaming capacity of inner spray foam dust control technology,which is combined two foaming method of network and spoiler together using porous helical blade. The principle and advantages of gas-liquid mixed porous spiral foam generator is described. Influence between static pressure and the turbulent kinetic energy of foaming device by key dimensions is proved through numerical simulation. Influence between foaming pressure loss and foaming properties of foaming device by different components is verified by experiments.Making EBZ260 roadheader spray delivery system as a model in the laboratory, roadheader spray foam for dust suppression simulation experiment system is constructed and combined experimental of spray foam inside the roadheader for dust suppression is realized. Under the condition of the water flow is 1.6m3/h, the water supply pressure is 2.13 MPa, the supply air flow rate is 45~60m3/h and the supply pressure is 0.45~0.56 MPa, the foaming agent addition ratio is about 1%, which can realize the foaming capacity of 46.9m3/h, the foaming ratio reached 28.74 times,the low ratio of liquid is stabilized by water jet suction device. The gas-liquid mixed porous spiral foam generator can foam efficiently and foam injection pressure is sufficient.