A numerical model for simulating residence time distribution of turbulent flows in helical static mixers is proposed and developed to improve the understanding of static mixers. The predicted RTD is presented in terms of different volumetric flow rate to illustrate the complicated flow patterns that drive the mixing process in helical static mixers. The computed results are also used to predict the amount of mixing that occurs within a mixing device. Such theoretical estimates need, however, always to be thoroughly checked against observations in Static mixer. The experimental unit is an annulus in which helical elements are brazed on the outer surface of inner tube. The helical elements are arranged alternatively in right and left-handed format. RTD studies were performed by injecting a pulse and the response at the outlet was measured. To check the reliability and the quality of the theoretically estimated RTD from the simulation by the application of the model equation, a comparison of the same with those obtained from observed data using statistical characteristics is done. Comparison between RTD curves shows that motionless mixture can improve the performance of reactor.