Characterization of Friction Loss in Pelton Turbine(1) (original) (raw)

The Pelton turbine can be used as a two-phase expander. The characterization of the Pelton turbine as two-phase expander consists in analyzing the power loss sources to evaluate the machine performance. In this study, the friction loss of a Pelton wheel is presented. A Pelton wheel has been realized with aluminum buckets and has been mounted on a test bench. The examination of experiments dealing with drag force in the Pelton turbine shows that the wheel friction losses are an important part of turbine losses when it is shrouded and operate in high density atmosphere. Experimental results show that losses by drag friction of a turbine enclosed in 0.5 MPa of R-134a atmosphere and rotating at 3000 rpm, can reach 3000 W, which is equal to the available power in the fluid jet. A CFD model of Pelton wheel has been done to analyze and reduce the friction losses in order to develop an efficient turbine. Modeling shows that with lowering the number and the size of the buckets, friction loss can be decreased by 30%.