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.