Performance of a low-head pico-hydro Turgo turbine

Turgo turbines are reported to be reliable, robust and able to operate efficiently over a range of flow rates. They are typically used in medium- to high-head applications. In this paper, the operation of a single-jet Turgo turbine outside of this typical application domain is investigated, at low heads of 3.5 m down to 1 m, a typical head range available for remote communities. A 2D quasi-steady-state mathematical model with low computational requirements is developed, to arrive at a base-line design. Experimental results from this base-line design show the model to predict torque within 5% at the peak power point across the investigated head range. The model requires no calibration and is therefore suitable for rapid performance estimation of first designs. As the head decreases and the jet diameter increases, 3D effects become more significant, reducing the accuracy of the model. Therefore, the model is used to identify important parameters for a further experimental study: Here, these parameters are varied from the base-line design to provide the sensitivity of the efficiency to each parameter. This study improves the turbine’s performance by 5% relative the base-line design to 91% peak jet-to-mechanical power efficiency at 3.5 m head, and at 1.0 m head provides a 20% improvement in the efficiency to 87%.