Measurement And Analysis Of The Stress On The Surface Of Impeller Blade

The surface stress of the impeller blade is effected by many factors. The most important effect factors on the surface stress of the impeller blade, such as impeller rotation speed, location of impeller from the bottom, height of liquid and impeller tip angle, had been studied. A newly built agitating tank with 1.6m diameter, flat bottom was made available for the measurements. Measurements were carried out by using a strain gauge system which was glued the 45 rosettes up and down the CBY impeller blade surface. An electrical resistance strain gauge technique and a computer data collector rotating with impeller shaft were used in this system.The following conclusions may be made from the work:The surface stress of the impeller blade is fluctuant. The stress amplitude is ?0% of the mean stress. The maximum stress range locates at the 0.3R from the shaft.With the variety of the impeller tip angle from 17.6 to 23 , the surface stress of the agitator blade is increased.A critical value of the liquid height to tank diameter ( Z/T ) ratio exist. When Z/T ratio is greater than the critical value, the surface stress increase with the Z/T. When it is less than that, the surface stress decrease with the Z/T.This work could be an important reference for the determination the thickness of the blade and the design of the industrial impeller.