The design and optimization of foam nozzle for dust control underground coal mine

In order to obtain the optimal key structure parameters of foam nozzle applied to dust control underground coal mine, the design principle of foam nozzle was elaborated. Meanwhile the compressibility of foam was defined and the calculation formula about volume change of foam caused by pressure variation was deduced. From the formula, the volume expansion would occur when the foam flows out the pipeline, if the two gaps were set at the pipeline end symmetrically, the fan-shaped diffusion would appear along the gaps because of the volume expansion. Based on these principles, the internal structure of the nozzle was designed and the key structure parameters were theoretically calculated. By using the experimental system constructed in the lab, a series of optimized experiments were carried out, and the optimum sizes of the key structure parameters were obtained. The foam nozzle with optimum structure parameters was produced, and the simulation spraying experiments and the practical application were carried out using the produced foam nozzle. The results of experiments and application show that the foam nozzle has the advantages, such as large flow quantity, far jetting distance, uniform dispersion and wide diffusion range. Furthermore, the foam spraying from the foam nozzle can effectively cover the dust sources, which will have a remarkable effect on dust control at working face underground coal mines.