Edición No. 21, Issue II, Enero 2025
1. INTRODUCCIÓN
The generation of electric energy in several Latin
American countries has been linked to the use of fossil
fuels in their energy matrix, causing a problem of
environmental pollution, which has led to the search for
other less invasive, more efficient, and environmentally
friendly energy sources. The development of the
electricity sector takes shape when focusing on
improving the energy matrix with renewable energy
such as hydroelectric power plants. By adopting an
improved energy matrix, Ecuador not only benefits the
electric distribution field but also avoids contamination
and danger to the country's fauna and flora. Pinargote et
al. [1] 39 MW, of which 5243.37 MW correspond to
renewable energy sources, representing 64.9 %. Of the
renewable sources, 5082.35 MW corresponds to the
participation of the hydraulic source, representing
96.9 %. Only 3.1 % correspond to wind, solar, and
biomass energy together [2].
Rojas et al. [3] detail that in the last seven years
hydroelectric power plants within the energy matrix will
represent 93% of the effective generation power,
however, the development and maintenance of such
infrastructure must be considered. Fonseca et al. [4]
propose a proportional distribution to the average water
flow contributed by each municipality within the
catchment area of the hydroelectric power plant and the
size of the area flooded by its reservoir through an
analysis of the balance between precipitation and
evapotranspiration for all municipalities in Brazil,
yielding only a 3 % difference concerning the observed
water flow. As a result of the proposed methodology,
the number of municipalities benefited increased from
41 to 167 drainage areas, providing financial resources
to the municipalities and allowing them to invest in
conservation techniques to ensure the maintenance of
water resources [5].
Liu et al. [6] describe an analysis focused on the
concentration of sediment and silt in the turbined water,
the Kaplan, Pelton, and Francis turbines which are the
most used in hydroelectric plants are the focus of the
study considering as parameters of analysis of the silt
density, sediment size, velocity and direction. Using
three concentrations of sand 25, 50, and 85 kg/m3 with
different sizes 0.531, 0.253, and 0.063 mm, where the
increase of quantity and size causes damage by
cavitation for which they propose to cover the surfaces
that suffer when losing their efficiency and in a direct
way the reduction of the generation time. Chavarro [7]
details a Kaplan turbine a CFD modeling under various
functional parameters that determine its wear, these
parameters are pure water, cavitation erosion, erosion
by silt, and combined erosion, like the Francis and
Pelton turbine the operation of the Kaplan turbine under
sediment erosion, generates efficiency drop of 2.47%
with the increase in the diameter of the sediment to
100 μm and the concentration of sediment
10000 ppm [8], [9].
Sangal et al. [10] state that due to the sedimentation
of the turbine water, the turbine components wear,
especially the guide vanes, when performing a fluid
dynamic analysis and simulation of the guide vane of
the Francis model turbines with different thicknesses of
17 and 21 mm, through a geometric study of both vanes
it was found that, by increasing the blade thickness, the
line of attack (chord) of the current blade
(21 millimeters thick), has a small linear deviation of
0.13 millimeters concerning the original blade
(17 millimeters thick), causing an increase in the flow
angle [11].
Rai et al. [12] studied the erosion caused by
sedimentation on different materials under the same
erosive and hydraulic conditions where they conducted
experiments simultaneously with varying ranges of
velocity, exposure duration, sediment size, and
concentration on 1:8 scale reduced Pelton cubes of a
hydroelectric plant in India, for application on Pelton
turbines made of 6 materials such as 3 types of steel,
2 types of coatings and bronze for heights up to 200 m
the scale. Sun et al. [13] mention the study of sediment
abrasion, cavitation erosion, and synergistic erosion in a
rotating disk test rig. They also compared the anti-
abrasion properties of HVOF high-speed oxy-fuel
sprayed stainless steel and HVOF sprayed martensitic
WC-CO-Cr stainless steel. They found that the latter is
more suitable for the sediment-laden flow environment.
Cruzatty et al. [14] analyzed by CFD the runner
blades of a Francis turbine where they presented a
higher erosion rate on the suction side near the trailing
edge. The presence of higher sediment erosion is the
trailing edge of the suction side, the result of the
numerical analysis reflects that the erosion damage
increases significantly for higher flow rates when the
guide vane opening exceeds 85 % opening considering
the closed position as a reference. Noon and Kim [15]
describe a CFD analysis where the leakage flow
generates a step vortex, which moves away from the
wall as it moves downstream, decreasing the intensity,
and demonstrating the minimization of the coalescing
impact of secondary flow and sediment erosion. Several
studies show that the efficiency of the Francis turbine
varies between 3 and 6 % depending on changes in
sediment concentration and secondary flow phenomena.
However, a loss of between 2 and 3.5 mm of channel
thickness is observed.