Optimal Design and Experimental Validation of a Turgo Model Hydro Turbine

Abstract

This work presents the development and application of a new optimal design methodology for Turgo impulse hydro turbines. The numerical modelling of the complex, unsteady, free surface flow evolved during the jet-runner interaction is carried out by a new Lagrangian particle method, which tracks a number of representative flow elements and accounts for the various hydraulic losses and pressure effects through special adjustable terms introduced in the particle motion equations. In this way, the simulation of a full periodic interval of the flow field in the runner is completed in negligible computer time compared to the corresponding needs of modern CFD software. Consequently, the numerical design optimization of runner geometry becomes feasible even in a personal computer and affordable by small and local manufacturers. The bucket shape of a 70 kW Turgo model is properly parameterized and numerically optimized using a stochastic optimization software to maximize the hydraulic efficiency of the runner. The optimal runner and the rest turbine parts are then manufactured and installed in the Lab for testing. Detailed performance measurements are conducted and the results show satisfactory agreement with the numerical predictions, thus validating the reliability and effectiveness of the new methodology.

Flow Modeling in Pelton Turbines by an Accurate Eulerian and a Fast Lagrangian Evaluation Method

“…Simulation (FLS) [8,9] is a single-phase flow simulation method, and it is based on the tracking of a representative number of fluid particles in order to model and calculate the flow pattern and the energy exchange in the rotating runner of impulse hydro turbines. The exact water-air interface pattern is not required for such computations, though the flow width on the bucket surface could be estimated from the properties of the tracked particles.…”

“…Commercial software has been developed and used based on Eulerian meshtype codes like Ansys-CFX [2,3] and Ansys-Fluent [4,5] that are designed to simulate the flow in various physical problems. Also, a number of noncommercial software tools have been developed like the Open FOAM [6], as also various Lagrangian approaches, like the Smoothed Particle Hydrodynamics method [7] or other in-house codes like the Fast Lagrangian Simulation (FLS) [8,9] that were developed to solve specific flow problems.…”

“…In order to reduce the computational cost, a particulate method based on the Lagrangian approach has been developed by the Laboratory of Hydraulic Turbomachines, NTUA [8,9]. This Fast Lagrangian Simulation (FLS) method introduces appropriate adjustable terms in the flow particle equations to approximate the various viscous and pressure effects of their trajectories.…”

Numerical Investigation of the Spear Valve Configuration on the Performance of Pelton and Turgo Turbine Injectors and Runners

“…12) was taken from a previous numerical optimization study [8], and its main characteristics are given in Table 1. Using a nozzle diameter of 100mm and the design head of 48m, the 110-70 and 90-50 injectors produced flow rates of 96.9 kg/s ±0.6% for both the 2D axisymmetric and the 3D simulations with the branch pipe.…”

“…Due to the high complexity and unsteadiness of the flow during jet-runner interaction, the development of impulse turbines is difficult and requires sophisticated equipment for flow observation [4][5][6][7] or high cost computational resources for accurate numerical analysis [8][9][10][11][12][13][14][15][16]. There are some studies available where a selection of injector designs are modelled and compared using CFD [17][18][19] or using a visual analysis [20][21][22].…”