In order to solve the problem of knowledge acquisition in equipment fault diagnosis,the paper introduces a method based on improved particle swarm optimization. Firstly the paper transforms the nonlinear equations which describe the system into optimization problem with constriction. Since the equation is nonlinear and multidimensional ,standard particle swarm cant solve the problem due to the weakness of premature. So one improved particle swarm optimization is proposed. During the evolution, density evaluation, clone and mutation operator is proposed under the thought of immunity. The results of simulation show that the immune particle swarm optimization can simulate effectively and acquire the system knowledge.

Based on the method FW-H acoustic model, how the parameters influence acoustic characteristics of the Hartmann acoustic generator were studied, which are resonator length, spacing between the jet and resonator tube, the diameter of resonator tube. The conclusions were induced just as below. The total sound pressure level (SPL) increases with the length of resonator tube, while the magnitude of fundamental frequency is reverse. And the total SPL oscillates with the increase of spacing between jet and resonator, and the oscillating distance period increases with diameter of resonator tube. And the Hartmann generator with larger diameter of resonator tube can produce a higher SPL. The results of the paper provide the instructing meaning for the application of the Hartmann acoustic generator.