Propeller Series

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Stephan Helma - One of the best experts on this subject based on the ideXlab platform.

  • Surprising Behaviour of the Wageningen B-Screw Series Polynomials
    Journal of Marine Science and Engineering, 2020
    Co-Authors: Stephan Helma
    Abstract:

    Undoubtedly, the Wageningen B-screw Series is the most widely used systematic Propeller Series. It is very popular to preselect Propeller dimensions during the preliminary design stage before performing a more thorough optimisation, but in the smaller end of the market it is often used to merely select the final Propeller. Over time, the originally measured data sets were faired and scaled to a uniform Reynolds number of 2 · 106 to increase the reliability of the Series. With the advent of the computer, polynomials for the thrust and torque values were calculated based on the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients K T and K Q versus the advance coefficient J . Changing the presentation from these diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple extrema when optimising for efficiency or even no optimum at all for certain conditions, where an optimum could be expected. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT’17 and smp’19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all Propellers of the Wageningen B-screw Series.

  • Surprising Behaviour of the Wageningen B-screw Series Polynomials
    2020
    Co-Authors: Stephan Helma
    Abstract:

    Undoubtedly the Wageningen B-screw Series is the most widely used systematic Propeller Series. It is very popular to preselect Propeller dimensions during the preliminary design stage before performing a more thorough optimization, but in the smaller end of the market it is often used to merely select the final Propeller. Over time the originally measured data sets were faired and scaled to a uniform Reynolds number of 2·106 to increase the reliability of the Series. With the advent of the computer, polynomials for the thrust and torque values were calculated based on the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients KT and KQ versus the advance coefficient J. Changing the presentation from these diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple optima when optimizing for efficiency or even no optimum at all for certain conditions. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT’17 and smp’19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all Propellers of the Wageningen B-screw Series.

  • Surprising Behaviour of the Wageningen B-screw Series Polynomials
    2019
    Co-Authors: Stephan Helma
    Abstract:

    Undoubtedly the Wageningen B-screw Series is the most widely used systematic Propeller Series. It is very popular to preselect Propeller dimensions during the preliminary design stage, but often it is also used to merely select the final Propeller. Over time the originally measured data sets were faired and scaled to a uniform Reynolds number (based on chord length and section advance speed) of 2·10⁶ to increase the reliability of the Series. With the advent of the computer polynomials for the thrust and torque values were calculated from the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients K_T and K_Q versus the advance coefficient J. Changing the presentation from open-water diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple optima when optimizing for efficiency or even no optimum at all for certain conditions. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT'17 and smp'19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all Propellers of the Wageningen B-screw Series.

Terry E Brockett - One of the best experts on this subject based on the ideXlab platform.

  • on the maximum efficiency of some marine propulsors in open water
    International shipbuilding progress, 2003
    Co-Authors: Terry E Brockett
    Abstract:

    Available performance data of selected open, contra-rotating and ducted propulsors operating in a uniform onset field, are assembled to display the maximum efficiency as a function of thrust-loading coefficient, C T = -T/(ρV 2 R R 2). Satisfactory correlation is presented between this observed best efficiency and estimates from a numerical method based on an inviscid lifting-line representation of the rotor, or other blade row, plus, when appropriate, an axi-symmetric panel-method analysis of the duct and hub surfaces. Viscous drag is added empirically as a local blade-section friction coefficient. For the open-Propeller Series and various sets of conventional accelerating ducted propulsors, the maximum efficiency of the dacted propulsors is greater by several percent at a C T = I and by about 5 percent (straight difference in values) at a C T approaching 10. The contra-rotating configuration displays a greater increase in the observed maximum efficiency at reduced C T values compared to the accelerating ducted propulsor but at C T > 2 the accelerating ducted units develop greater efficiency. Only at reduced, thrust levels is there an indicated beneficial interaction between the blade rows of a contra-rotating propulsor compared to a simple thrust division without interactions.

M.m. Moustafa - One of the best experts on this subject based on the ideXlab platform.

  • Optimum design of B-Series marine Propellers
    Alexandria Engineering Journal, 2011
    Co-Authors: M.m. Gaafary, H.s. El-kilani, M.m. Moustafa
    Abstract:

    Abstract The choice of an optimum marine Propeller is one of the most important problems in naval architecture. This problem can be handled using the Propeller Series diagrams or regression polynomials. This paper introduces a procedure to find out the optimum characteristics of B-Series marine Propellers. The Propeller design process is performed as a single objective function subjected to constraints imposed by cavitation, material strength and required Propeller thrust. Although optimization software of commercial type can be adopted to solve the problem, the computer program that has been specially developed for this task may be more useful for its flexibility and possibility to be incorporated, as a subroutine, with the complex ship design process.

Stuart D. Jessup - One of the best experts on this subject based on the ideXlab platform.

Gert Kuiper - One of the best experts on this subject based on the ideXlab platform.

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