Numerical calculations of propeller shaft loads on azimuth propulsors in oblique inflow

Amini, Hamid; Sileo, Lucia; Steen, Sverre

doi:10.1007/s00773-012-0176-z

Cited by 22 publications

(13 citation statements)

References 4 publications

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“…It has to be stressed that the BEMT model is inherently quasi steady, because the Prandtl-Betz condition implicitly assumes the balance of the load developed by the blade strip and the vorticity (constant) carried by trailing vortex. However, as long as the inflow is time-varying, this equilibrium condition is not suddenly met and its lag depends on the time rate of circulation detached at the trailing edge of the airfoil, because it is responsible of an additional perturbation to the blade section [36].…”

Section: Models and Methodologiesmentioning

confidence: 99%

Experimental and Numerical Investigation of Propeller Loads in Off-Design Conditions

Ortolani

Dubbioso

Muscari

et al. 2018

JMSE

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The understanding of the performance of a propeller in realistic operative conditions is nowadays a key issue for improving design techniques, guaranteeing safety and continuity of operation at sea, and reducing maintenance costs. In this paper, a summary of the recent research carried out at CNR-INSEAN devoted to the analysis of propeller loads in realistic operative scenarios, with particular emphasis on the in-plane loads, is presented. In particular, the experimental results carried out on a free running maneuvering model equipped with a novel force transducer are discussed and supported by CFD (Computational Fluid Dynamics) analysis and the use of a simplified propeller model, based on Blade Element Momentum Theory, with the aim of achieving a deeper understanding of the mechanisms that govern the functioning of the propeller in off-design. Moreover, the analysis includes the scaling factors that can be used to obtain a prediction from model measurements, the propeller radial force being the primary cause of failures of the shaft bearings. In particular, the analysis highlighted that cavitation at full scale can cause the increment of in-plane loads by about 20% with respect to a non-cavitating case, that that in-plane loads could be more sensitive to cavitation than thrust and torque, and that Reynolds number effect is negligible. For the analysis of cavitation, an alternative version of the BEMT solver, improved with cavitation linear theory, was developed.

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Section: Models and Methodologiesmentioning

confidence: 99%

Experimental and Numerical Investigation of Propeller Loads in Off-Design Conditions

Ortolani

Dubbioso

Muscari

et al. 2018

JMSE

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“…Thrust Model. First, we estimate C T using the axial momentum theory [13,14]. The major assumptions are as follows: (i) no rotational motion is imparted to the flow by the propeller disk; (ii) the Mach number is small, so the fluid can be assumed to be incompressible; and (iii) the flow is steady as the propeller is assumed to be a thin disk (of cross-section area A), through which air passes, and the induced velocity is assumed to be constant at all points which lie on the same radius.…”

Section: Propeller Static Thrust-rpm Modelingmentioning

confidence: 99%

“…General momentum theory is a magnificently huge theory which deals with the flow characteristics across the propeller disk at a much broader level than Blade Element Theory as discussed in [26] with all its development and assumptions around it. We first estimate C T using momentum theory [13,14]. A simplified model of a propeller stream tube is shown in Figure 1.…”

Section: A Blade Element and Momentum Theorymentioning

confidence: 99%

Propeller Force-Constant Modeling for Multirotor UAVs from Experimental Estimation of Inflow Velocity

Gupta

Abdallah

2018

International Journal of Aerospace Engineering

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Design and simulation of an unmanned aerial vehicle (UAV) highly depends on the thrust produced by a motor-propeller combination. The aim of this paper is to model a generalized mathematical relationship between the motor RPM and the corresponding thrust generated for the preliminary design process of low Reynold’s number applications. A method is developed to determine a generalized mathematical model which relates inflow velocity to coefficient of thrust using experimental data from 291 motor-propeller data points, comprising of input RPM and corresponding output thrust. Using this relationship, the Force Constant is calculated, which defines each Thrust-RPM mathematical model. In the first part, expression of the inflow ratio obtained from Blade Element and Momentum Theory (BEMT) is approximated to a simplified form. In the later part, the proposed mathematical model is validated against two new sets of pairs of motor-propeller combinations. A special note in the Appendix talks about the application of this mathematical model. The computed results are found to be in good agreement with the experimental data.

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“…Junglewitz and El Moctar [18] investigated the interaction between the podded propulsors' components in azimuthing condition. Recently, Guo et al [21], Amini et al [19], Arikan et al [22] and Shamsi and Ghassemi, [23] used unsteady RANS solver for simulating the flow around pulling and pushing podded propellers with yaw angles. None of the previous research has studied the propulsive performance of the puller and pushers podded propulsors in or near bollard pull conditions.…”

Section: Introductionmentioning

confidence: 99%

Numerical Research on Usage of Podded Propulsors in Ice Management

Islam¹,

Jahra²,

Molyneux³

et al. 2015

All Days

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Although podded propulsor technology has existed for nearly two decades, there has been little research into the use of these propulsors for ice management. Full-scale ice management trials with azimuthing thrusters revealed that it was possible to break and clear ice with the propulsors' wake and that precise ice management could be achieved with the wake of this propulsion system. This means dynamic placement ofpropeller wake wash can facilitate ice breaking and ice management operations. This paper presents preliminary outcome of a research program to evaluate the potentials ofpodded propulsors as an ice management device.The kinematics i.e. the turbulence and velocity distribution in the propeller wake wash determines the capacity of the propulsor to break, push and clear the ice. In this research, efforts are made to model the propeller wash and data were predicted to quantify the capacity of a podded propulsor to clear ice under a range of operating conditions. A Reynolds-Averaged Navier-Stokes solver is used to predict the propulsive performance of a generic podded propulsor system in various operating conditions and configurations. The effects ofpropeller shaft speed and pod configuration are evaluated. The predicted propeller thrust and torque as well as the loads on the pod are compared with corresponding data acquired in a complimentary experimental program. The simulations and measurements are carried out for both puller and pusher configurations at or near bollard pull condition and in uniform inflow condition. Analysis demonstrates that the RANS solver can accurately predict the performance coefficients of the podded propulsor in straight-ahead condition in both puller and pusher configurations. The kinematics of the propeller wash at multiple downstream locations are studied only to reveal that the pusher propulsor may be more effective in clearing ice than the puller one because of less interaction between the propeller and the strut. The current work aims to provide insight into the effect of propeller shaft speed and pod configurations on the quality of the propeller wake that can be used for ice management.

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Numerical calculations of propeller shaft loads on azimuth propulsors in oblique inflow

Cited by 22 publications

References 4 publications

Experimental and Numerical Investigation of Propeller Loads in Off-Design Conditions

Experimental and Numerical Investigation of Propeller Loads in Off-Design Conditions

Propeller Force-Constant Modeling for Multirotor UAVs from Experimental Estimation of Inflow Velocity

Numerical Research on Usage of Podded Propulsors in Ice Management

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