Wind Tunnel Performance Tests of the Propellers with Different Pitch for the Electric Propulsion System

The geometry of a propeller is closely related to its aerodynamic performance. One of the geometric parameters of a propeller is pitch. This parameter determines the distance by which the propeller moves forward during one revolution. The challenge is to select a propeller geometry for electric propulsion in order to achieve the best possible performance. This paper presents the experimental results of the aerodynamic performance of the set of propellers with different pitch values. The tests were performed in a closed-circuit subsonic wind tunnel using a six-component force balance. The analyzed propellers were 12-inch diameter twin-blade propellers that were driven by a BLDC (brushless direct current) electric motor. The tests were performed under forced airflow conditions. The thrust and torque produced by the propeller were measured using a strain gauge. The analysis was performed for different values of the advance ratio which is the ratio of freestream fluid speed to propeller tip speed. Additionally, a set of electrical parameters was recorded using the created measurement system. The propeller performance was evaluated by a dimensional analysis. This method enables calculation of dimensionless coefficients which are useful for comparing performance data for propellers.

Design of Propeller Series Optimizing Fuel Consumption and Propeller Efficiency

This paper presents a comparison between different types of propellers operated in calm water to evaluate their performance behind hulls and in open-water conditions. A bulk carrier is chosen as a case study to perform the simulation and to evaluate the performance of several propeller series, namely the Wagengein B-series, Kaplan 19A, and MAU. Firstly, optimization procedures are performed by coupling a propeller design tool and a nonlinear optimizer to find the optimum design parameters of a fixed-pitch propeller. This optimization model aims to design the propeller behind the hull at the engine operating point with minimum fuel consumption and maximum propeller efficiency. The two main objectives of this study and the constraints are defined in a single fitness function to find the optimum values of the propeller geometry and the gearbox ratio. By considering the benefits of the single-objective over the multi-objective optimization problem, this model helps to find the optimum propeller for both defined objectives instead of only considering one of them, as in previous studies. Then, based on the optimized parameters, the propeller performance is calculated in open-water conditions. From the computed results, one can observe the importance of considering the hull–propulsor interaction in propeller selection.

Wake optimization of ducted propeller

Object and purpose of research. This paper discusses marine ducted propeller and the ways to ensure its target performance parameters. The purpose of this study was to mitigate unsteady forces on the propeller behind the duct struts. Materials and methods. Analytical estimates of propeller parameters and in-house KSRC methods for numerical simulation of ducted propeller behaviour. Main results. Calculations of effective wake behind duct struts taking into account the flow around hull and its append-ages. Calculations of unsteady forces for a standard propeller operating in this wake. Design of a propeller with increased blade skew. Calculations of unsteady forces for the new propeller in the initial wake. Wake field parameters contributing to mitigation of unsteady forces. Calculations for the new strut shape for wake optimization. Calculations of unsteady force amplitudes for standard propeller in the new wake. Conclusion. Ducted propeller discussed in this study was meant to illustrate how propeller wake properties, like unsteady forces, can be optimized without changing propeller geometry, only by means of curved duct struts.

Numerical investigation of mutual interaction between a pusher propeller and a fuselage

This article presents the numerical analysis of the aerodynamic impact of the fuselage on propeller performance in the pusher configuration and the propeller impact on the flow around the fuselage. The main aim of the presented investigation was to find the magnitude of the interaction between the propeller and the fuselage. This effect was evaluated based on the analysis of the change of the fuselage drag and the propeller thrust according to the change of the propeller's geometry. All obtained results allowed to prepare the methodology for choosing the best propeller geometry for the aircraft in the pusher configuration. During the investigation, the impact of the propeller geometry on the results was analysed. First of all, the change of the blade pitch ratio and the propeller radius was tested. Computation was made for numerous flight conditions and propeller rotation rate. As a main result, the relation between the propeller performance and the fuselage in the pusher configuration was found. Especially, the significant influence on the propeller thrust caused by the fuselage and the influence on the fuselage drag caused by the propeller were observed. Finally, all the obtained outcomes were used to create a knowledge base, which was next used to select the best propeller geometry to satisfy the required power condition for a level flight for the newly designed aircraft PW-Chimera.

NUMERICAL STUDY OF ACOUSTIC CHARACTERISTICS OF A DTMB 4119 PROPELLER DUE TO TIP RAKE

The impact of increased Underwater Radiated Noise (URN) over the past two decades on marine mammals has resulted in the pressing requirement to reduce it. Shipping contributes immensely to the URN. Propeller noise is a major source of URN. The reduction in Propeller noise can hence significantly help in the reduction of URN. With the sole objective of improving the hydrodynamic performance of propellers ways to prevent cavitation are being developed. However, the reduction of non cavitating noise produced by the propeller would still remain a challenge. The change in the propeller geometry can modify the acoustic characteristics. In this present study, effect of modifying the tip of DTMB4119 propeller on the acoustic and hydrodynamic characteristics is presented. The change in the flow pattern at the tip due to introduction of tip rake is also discussed. The SPL has been calculated by using the two-step Ffowcs William and Hawkings (FW-H) equations from the pressure distribution at various points around the propeller. SPL at various points in the downstream and propeller disk plane are numerically predicted and discussed.