Dual-operating-point blade optimization for high-speed propellers
نویسندگان
چکیده
Propeller blade design for fast ships is often driven by cavitation constraints. A tradeoff exists, where larger chord lengths and section thicknesses typically improve cavitation performance but result in lower efficiency. Typically, chord lengths are optimized for the design condition (ship endurance speed), with some specified margin to prevent cavitation off-design (at maximum ship speed). Cavitation performance at the maximum speed is considered post-facto, and blade shape often needs to be modified for cavitation considerations in high-speed operation. This paper presents an improved method for blade shape optimization. The present method simultaneously considers the cavitation performance at the endurance speed design point and a maximum speed off-design point, and blade chord lengths and thicknesses are set to prevent cavitation at both operational conditions. During the present design optimization routine, the on-design load distribution is optimized, and the off-design performance is determined, such that the chord lengths can be set to a minimum that still prevents cavitation at both the onand off-design conditions. A case study is presented, considering the notional design of a propeller for the U.S. Navy DDG51 destroyer-class ship. Propellers designed using standard chord/thickness optimization procedures are compared to those designed using the present procedures. Cavitation performance is compared for the two design methods.
منابع مشابه
Psychoacoustic evaluation of noises produced by propellers with asymmetrical blade spacing
Instrumental evaluations (e.g. Dobrzynski, InterNoise 90) showed that propeller noise can be reduced by asymmetrical blade spacing. Compared to conventional propellers with 6 blades and symmetrical spacing of 60°, propellers with asymmetric spacing of 15° produce about 3 dB(A) less level, in particular for high helical blade tip Mach numbers HBTMN. Since the aerodynamic propeller performance is...
متن کاملNumerical and Experimental Investigations for Design of a High Performance Micro-hydro-kinetic Turbine
Design and manufacturing of a high performance micro-hydro-kinetic turbine is discussed in the present paper. The main goal is manufacturing an equipped experimental model of hydro-kinetic turbine with highest energy absorption from water current. A multi-shape ducted turbine comprised of a multi-part diffuser was manufactured that can be converted to many experimental models for studying vario...
متن کاملApproach Considerations in Aircraft with High-Lift Propeller Systems
NASA’s research into distributed electric propulsion (DEP) includes the design and development of the X-57 Maxwell aircraft. This aircraft has two distinct types of DEP: wingtip propellers and high-lift propellers. This paper focuses on the unique opportunities and challenges that the high-lift propellers—i.e., the small diameter propellers distributed upstream of the wing leading edge to augme...
متن کاملPropeller blade stress estimates using lifting line theory
OPENPROP, an open-source computational tool for the design and analysis of propellers and horizontal-axis turbines, is extended to provide estimates of normal stresses in the blades for both onand off-design operating conditions. The numerical model is based on propeller lifting theory, and the present implementation of the code includes an analysis capability to estimate the off-design perform...
متن کاملOptimal Trajectory of Flexible Manipulator with Maximum Load Carrying Capacity
In this paper, a new formulation along with numerical solution for the problem of finding a point-to-point trajectory with maximum load carrying capacities for flexible manipulators is proposed. For rigid manipulators, the major limiting factor in determining the Dynamic Load Carrying Capacity (DLCC) is the joint actuator capacity. The flexibility exhibited by light weight robots or by robots o...
متن کامل