The velocity distribution of the tube in the kenics static mixer was simulated by using the CFD software．And flow field of partial type static mixer was measured by using LDV （Laser Doppler Velocity）． The discussions were given to the
effect of length －to－diameter ratio of mixing elements on the velocity distribution and turbulent property in kenics static mixer．The results show that the trend of the velocity of different direction and turbulent kinetic energy along axis is changeless with the variety of the length －to－diameter ratio of mixing elements ．But the value of amplitude is influenced．When the length－to－diameter ratio of mixing elements is little，the value of amplitude of velocity of different direction and the slope is bigger．The effect of the radial velocity is obvious and that of axial velocity is minor．With the length－to－diameter ratio of mixing elements diminution，the turbulence degree and turbulent kinetic energy enhanced and the increasing of the velocity is greater than the variation of velocity.

The turbulent flow characteristic in a stirred mixer with propeller was predicted based on multi-reference frame by using CFD turbulent model. Some detailed information about the velocity and turbulence kinetic energy was obtained. The simulated results show that the mean velocities increase firstly then decrease as radial position increasing, while the values of mean velocities close to the impeller are larger which were found in good agreement with the experimental results reported in the literature. Though the velocity distributions at different axial position above the stirrer are also much smoother, the values of velocity increase firstly then decrease in the discharged zone. The turbulence in the discharged zone tends to be nonuniform and the magnitude of the turbulent kinetic may have 7~9 times difference at the same axial or radial position. It is priority to select propeller for the axial speed field as main field, long distance transmission compared with traditional typical three-blade impeller of 45°.

The acoustic emission signals were measured during plastic deformation and crack propagation in Q235-B and 0Cr18Ni9 stainless steel.Wavelet transform was applied to analyze inspection signal for investigating the acoustic emission characteristics of material. The results show that the acoustic emission signal of carbon steel is analyzed by six-layer db5 wavelet transform, the most energy is concentrated in d5 level.Peak frequency is located in the range of 166~176 kHz.Energy ratio in d5 level is higher during crack propagation than palstic transform.While the acoustic emission signal of stainless steel through the same wavelet transform, the most energy is concentrated in d6 level.Peak frequency is located in the range of 88～112 kHz. Energy ratio in d6 level is higher during crack propagation than palstic transform.

The characteristics of acoustic signal for pipe leakage and general wavelet primary function were analyzed. It concludes that the suitable primary functions for acoustic signal of pipe leakage are Daubechies wavelet and Symlet wavelet. The experiments of the acoustic inspection were conducted in water leakage of the carbon steel pipe and the wavelet transform of the leakage signal was done by db5 and sym5 wavelet. It shows that the most energy is a6 level signal energy and the peak frequency of the signal focus on 2.90~3.81 kHz. The maximum relative error of two different wavelet transforms is 0.77% in the energy analysis and 5.17% in frequency analysis.

The characteristic of flow resistance in the new type static mixers was investigated based on the microscope flow character by using the computational fluid dynamics(CFD) software. It can be seen from the velocity vectors of axial cross-sections that there was the spin flow, reverse to the revolving direction of the mixer element groups in the new type static mixers. The relationship among all factors influencing flow resistance in the static mixers was simplified by using the dimensional analysis and π theorem. A general relationship of friction coefficient of the flow resistance was gained by data reduction and regression. It offers the theoretical base for the industry application.