Effects of non-sinusoidal pitching motion on energy input performance of micro-linear turbine cascade

Abstract

In this paper, a numerical simulation of a micro-linear turbine cascade is presented. The upstream stay vane and downstream guide vane were surrounded by incompressible flow, and the guide vane was modeled with forced pitching motions. The implicit immersed boundary method was used as the moving boundary flow solver. To seek a better understanding of the influence of the motion parameters on hydrodynamic characteristics and input power of the oscillating guide vane, the forced motion of a non-sinusoidal oscillating guide vane was first investigated for different reduced frequencies and profile parameters. Second, the instantaneous hydrodynamic behavior was simulated for different motion combinations and Reynolds numbers. The results showed that the reduced frequencies and profile parameters of the pitch movement had a large influence on the input power, and the peak of the input power at f∗ = 0.22 was nearly 9.41 times that at f∗ = 0.074, but the input power was not sensitive to the motion combination and Reynolds number. However, the Reynolds number had a large influence on the drag, and the maximum drag coefficient for Re = 6.65 × 105 was 4.566; however, it was only 0.5912 for Re = 6.65 × 104.