## 4 Analysis of Experimental Results
### Load Characteristic Analysis
The distributions of the blade axial force and hydrodynamic load thrust in the blade profile are shown in Figure 13. When the blade exits the ice-propeller contact area, the thrust of the blade shows a significant reverse peak due to the influence of water. This shows that the axial force produced by ice-propeller milling is opposite to the hydrodynamic direction of the blade. During ice-propeller milling, with the rotation of the blade, the axial force changes at approximately 0 N. In ice-water-propeller interaction, with the rotation of the blade, the thrust gradually decreases, and the farther the distance  
Figure 11: Time-domain variation curves of the propeller load in different milling environments: (**a**) \(T_{r}\)(**b**) \(Q\). from the ice blocked area, the smaller the thrust of the blade. When the blade contacts with the ice again, the load increases and enters the next cycle. In Figure 12b, the presence of water causes a significant increase in the tangential force of a single blade. This is mainly because the resistances generated by the blade and water are in the same direction as that generated by ice milling, resulting in a superposition of the tangential forces. The thrust and tangential force of the blade are less than those of the atmospheric pressure owing to the influence of sheet cavitation and tip vortex cavitation in the decompression condition. Figure 8:0 Time-domain variation curves of single-blade load in different milling environments: (**a**) \(T_{X}\); (**b**) \(T_{T}\); (**c**) \(Q_{X}\); (**d**) \(Q_{Y}\); (**e**) \(Q_{Z}\). Figure 12c-e show the time-domain variation curve of the torque in three directions of a single blade. It can be observed from the figures that the torque in the \(Y\)-direction is the largest, and the torque in the \(Z\)-direction is the smallest. This is mainly because the arms of the force in the \(Z\)-direction and the force in the \(X\)-direction are the largest; therefore, the torque in the \(Y\)-direction is the largest. From the perspective of the overall change law of the curve, the presence of water causes an overall increase in the torque of a single blade. In particular, when the blade exits the ice block, the presence of water causes a significant increase in the torque of a single blade, because the force between the blade and water is in the same direction as that between the blade and ice. From the increase in the curve in the figure, the force and torque in the three directions of the blade in the decompression condition are less than those under atmospheric pressure, which is due to the influence of the cavitation on the blade surface. In order to compare the variation law of the load on the propeller and single blade under different propeller rotational speeds, inflow velocities, and cavitation numbers, the mean value and peak value of the ice milling load and mixed load during ice-propeller milling in three different environments were extracted and compared, as shown in Figure 8:1  
Figure 14a,b compare the mean and peak values of the propeller thrust and torque with variable parameters in ice-propeller milling. It is evident from the figures that under the same propeller rotational speed and inflow velocity, the mean and peak values of the propeller thrust and torque are the largest when ice-water propeller milling occurs at atmospheric pressure, followed by that under the decompression condition, whereas the ice milling load of the propeller in air is the smallest. When ice-propeller milling occurs in air, the smaller the rotational speed of the propeller, the larger the mean and peak values of the propeller axial force and torque coefficients. This is mainly because the smaller the propeller rotational speed, the larger the angle of advance and contact area between the blade and ice, and the longer the axial contact length between the blade and ice.