3 Conclusions
(1) The distribution of the oil flow pulsation intensity along the
normal direction changes slowly in the central region, while the change
in the near-wall region is steep, and this trend becomes more obvious
with increasing particle concentration. In addition, the flow direction
pulsation intensity of oil decreases with increasing particle
concentration, and the difference gradually decreases.
(2) The distribution of the normal
pulsation strength of oil in the normal direction for different particle
sizes is roughly in the shape of a ”W”. The amplitude of the normal
pulsation intensity fluctuates greatly in the central region and
near-wall region. In addition, the influence of particle concentration
on the distribution of the normal pulsation intensity is
nonunidirectional.
(3) With increasing particle concentration, the mean value of the
fluctuation amplitude of the instantaneous flow velocity gradually
decreases, and the varying amplitude decreases simultaneously. However,
the fluctuation amplitude of the instantaneous normal velocity is not
obvious. With increasing particle concentration, the main frequencies of
the flow direction and normal direction velocities show a decreasing
trend.
(4) The distribution periodicity of the average flow velocity of oil is
more obvious. As the particle concentration increases, the average flow
velocity gradually increases. When the particle concentration is below
3.00 ppm, the average normal velocity decreases with increasing particle
concentration, while when the particle concentration exceeds 3.00 ppm,
the average normal velocity of the oil shows an increasing trend.