A review on the Surface-Piercing Propeller: Challenges and opportunities

The application of surface-piercing propeller (SPP) has been widely used in high-speed crafts due to possessing many favorable features. Due to the information gaps in the design of SPP, researchers have made great efforts to conduct hydrodynamic analysis of these propulsion systems. Despite the previous studies, there is still a considerable shortage in literature. In this article, a comprehensive review has been carried out on the experimental, theoretical, and experimental–theoretical studies in the field of SPP to introduce the strengths, limitations, and gaps in the previous research. The results of previous studies have also been presented in the form of benchmarking tables and statistical figures. Investigations have proved the inability of the numerical methods to simulate SPP. In recent years, the most precise methods of analyzing complex flows around SPP have been the computational fluid dynamics methods. The most suitable computational fluid dynamics method is the Reynolds-averaged Navier–Stokes method. Moreover, despite the heavy costs of experiments, the experimental approach is still the most reliable way of understanding the flow phenomena, studying the time-dependent dynamic behavior of propellers, and determining the hydrodynamic coefficients of thrust and torque. It can also serve to develop the numerical methods for comparing the results and reducing the errors of semi-experimental equations. Therefore, one of the primary objectives of future studies will be the comprehensive experimental analysis of various propeller blade profiles considering the effect of the variations of the trailing edge angle and the effects of the parameters influencing SPP, especially the shaft inclination angle.

Numerical Analysis on the Effect of Artificial Ventilated Pipe Diameter on Hydrodynamic Performance of a Surface-Piercing Propeller

Under the condition of large water immersion, surface-piercing propellers are inclined to be heavy loaded. In order to improve the hydrodynamic performance of the surface-piercing propeller, the installation of a vent pipe in front of a propeller disc is more widely used in the propulsion device of high speed planning crafts. Based on computational fluid dynamics (CFD) method, this paper studied the influence of diverse vent pipe diameters on hydrodynamic performance of the surface-piercing propeller under full water immersion conditions. The numerical results show that, with the increase of vent pipe diameters, the thrust and torque of the surface-piercing propeller decrease after ventilation, and the efficiency of the propeller increases rapidly; the low pressure area near the back root of the blade becomes smaller and smaller gradually; and the peak of periodic vibration of thrust and torque can be effectively reduced. The numerical results demonstrate that the installation of artificial vent pipe effectively improves the hydrodynamic performance of surface piercing propeller in the field of high speed crafts, and the increase of artificial vent pipe diameter plays an active role in the propulsion efficiency of the surface-piercing propeller.

Experimental study of immersion ratio and shaft inclination angle in the performance of a surface-piercing propeller

Surface-piercing propellers have been widely used in light and high-speed vessels because of their superior performance. Experimental study of these propellers is one of the most reliable and accurate ways which can provide details about the performance and effect of different design parameters on the performance of the surface-piercing propellers. In this research, a five-blade surface-piercing propeller was tested in the free surface water tunnel of Babol Noshirvani University of Technology in order to expand the available experimental data and database for future engineering designs. The effects of immersion ratio and shaft inclination angle on the propeller's efficiency and hydrodynamic coefficients were examined. A free surface water tunnel and a calibrated dynamometer with the measurability of the thrust forces and the torque of a propeller were used for this purpose. Comparing the obtained results with the existing semi-experimental equations shows that the equations presented in various geometric conditions are not accurate enough, and developing the existing database is necessary. The details of the obtained results showed that the hydrodynamic coefficients of the thrust and torque increased by increasing the immersion ratio, but the coefficient of hydrodynamic thrust and efficiency reduced. The results also indicated that the coefficient of torque increased by increasing the shaft inclination angle. The highest efficiency of the propeller was achieved in the range of 40 %–50 % immersion ratios at all angles of shaft inclination. For all immersion ratios, the maximum and minimum efficiencies were obtained at 0 and 15 shaft inclination angles, respectively. The best efficiency of the propeller was at 50 % immersion ratio and zero shaft inclination angle.

Modeling and Simulation of Planing-Hull Watercraft Outfitted with an Electric Motor Drive and a Surface-Piercing Propeller

A simulation model for a prismatic hard-chine planing hull watercraft (V-shaped keel with constant deadrise) with propulsion based on a 3-phase induction motor connected directly to surface-piercing propeller (SPP) and outfitted with a motor rotational speed controller was investigated, tested, and tuned. The modularity of the model developed enables straightforward substitution of diverse and more refined modules, or even attachment of additional ones to obtain greater level of detail or simulate more complicated processes. Industry trends do suggest an increasing interest in all-electric ship development as well as the use of surface-piercing propellers for small or medium-size craft. All-electric drive plants offer distinct advantages due to their flexibility in arrangements, ability to eliminate reduction gears in many cases, low maintenance requirements and wide range of available sizes as well superb load acceptance and dynamic matching to changing operational conditions. Employing electric drives onboard small craft with planing-hulls that achieve significantly higher velocities where arrangements and maneuverability are of critical design issues is a theme that has received increased attention by designers in recent years. Refined speed regulation and tracking compounded by the feature to produce fairly constant torque across a broad speed (rpm) range enables using of unconventional thrusters such as surface-piercing propellers to small craft. By investigating towing tank test data series for a surface-piercing propeller, development of a numerical simulation tool for unconventional thrusters was demonstrated. The surface-piercing propeller simulation model, as an artificial neural network (ANN), was coupled with a 3-phase induction motor as prime mover as well as dynamic propulsion shaft model and proportional-integral-differential (PID) controller. The various sub-models were finally integrated with a sub-model implementing Savitsky’s propulsion resistance method and calculation of equilibrium trim for planing hull modeling. Simulations were conducted using full-scale real-world conditions for a high-speed small craft developed for leisure and sporting activities, rapid close-range transit, reconnaissance and surveying etc. The planing-hull watercraft considered is amenable to minor hull modifications in order to house a 50 kW electric motor and a four bladed surface-piercing propeller. Simulations performed allowed a full assessment of model functionality as well as level of detail.