Exploring the Effect of Blade Interlacing Angle on Waterwheel Performance Based on VOF Model

To investigate the factors affecting the performance of the 3-blade undershot waterwheel, this paper uses VOF model to simulate the unpressurized flow in the open channel, and the waterwheel with different interlacing angles（0°, 20°, 40°, 60°） of adjacent blades is simulated non-constantly based on the SST k-ω turbulence model, PISO algorithm and slip-grid rotation model. The results show that when the interlacing angle of adjacent blades is 0°, the corresponding waterwheel has the widest and highest efficiency, and the pressure in the front and rear areas of the impeller is basically symmetrical distribution. As the interlacing angle increases, the difference between the front and rear pressure distribution gradually becomes larger. Under the same working condition, the average value of waterwheel torque for one cycle of rotation is 60°, 40°, 20° and 0° in the order of small to large, but the instability also increases in order. In addition, the efficiency of the waterwheel shows a increasing and then decreasing trend with the increase in the blade tip speed ratio; the fluctuation of torque decreases with the decrease in the blade tip speed ratio.