Effect of the pitch angle and of the number of blades on depression created under impellers

Abstract

This work presents a set of experiments concerning the behavior of several types of impellers regarding the depression formatted and operating in a specific range of rotations. Various mixer designs including a four pitched blades impeller, a six flat blades impeller and four two flat blades impeller were compared. Experimental data confirmed the analytical results previously obtained. The results showed that there are similarities regarding the effects generated by four pitched blades impeller and one of the two flat blades impeller. Also, it is found that two shortblade impeller produces the lowest depression of all tested impeller. The maximum depression produced by all type of impellers do not exceeds 120 mmH2O at 400 rpm, which is a small value to realize the vaporization of the fluid and to reach the cavitation. The equipment is not in danger to be destroyed. The numerical results obtained by experiments can be used in various practical applications.