Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions

M. Maasch, O. Turan, M. Khorasanchi, Ivy Fang

Research output: Contribution to conferencePaper

Abstract

In recent years many studies and real-life applications dealing with trim optimisation have shown that operating a ship at small trim angles can improve the energy efficiency by up to 5% depending on ship speeds and loading conditions. This efficiency gain mainly results from the re-positioning of underwater hull features, such as the bulbous bow or the stern bulb. Different to the above described approach the present study deals with operating a LNG Carrier at an extreme bow-up trim angle of Ɵ = −1.9 deg. In order to predict the performance, URANS virtual towing tank simulations in calm water were performed for both, nominal resistance conditions and self-propulsion conditions including cavitation. The numerical results, including the ship resistance, the nominal propeller wake field and the simulation of propeller cavitation in self-propulsion conditions indicated a largely improved performance. Due to a significant reduction in nominal resistance by up to 27.5% the ship selfpropulsion point in extreme trim conditions was found at a lower propeller rotation rate compared to level trim conditions. This also reduced the cavitation volume and finally resulted in a delivered power reduction of up to 28.8%.

Conference

ConferenceInternational Conference on Shipping in Changing Climates 2017
Abbreviated titleSCC 2017
CountryUnited Kingdom
CityLondon
Period5/09/176/09/17
Internet address

Fingerprint

Propellers
Liquefied natural gas
Cavitation
Propulsion
Ships
Ship model tanks
Water
Drag
Energy efficiency

Keywords

  • extreme trim operation
  • unsteady RANSE
  • calm water resistance performance
  • automatic wake analysis
  • self-propulsion performance
  • cavitation simulation

Cite this

Maasch, M., Turan, O., Khorasanchi, M., & Fang, I. (2017). Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions. Paper presented at International Conference on Shipping in Changing Climates 2017, London, United Kingdom.
Maasch, M. ; Turan, O. ; Khorasanchi, M. ; Fang, Ivy. / Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions. Paper presented at International Conference on Shipping in Changing Climates 2017, London, United Kingdom.10 p.
@conference{dfbc22aec6174e7f80a4b7546da36dd0,
title = "Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions",
abstract = "In recent years many studies and real-life applications dealing with trim optimisation have shown that operating a ship at small trim angles can improve the energy efficiency by up to 5{\%} depending on ship speeds and loading conditions. This efficiency gain mainly results from the re-positioning of underwater hull features, such as the bulbous bow or the stern bulb. Different to the above described approach the present study deals with operating a LNG Carrier at an extreme bow-up trim angle of Ɵ = −1.9 deg. In order to predict the performance, URANS virtual towing tank simulations in calm water were performed for both, nominal resistance conditions and self-propulsion conditions including cavitation. The numerical results, including the ship resistance, the nominal propeller wake field and the simulation of propeller cavitation in self-propulsion conditions indicated a largely improved performance. Due to a significant reduction in nominal resistance by up to 27.5{\%} the ship selfpropulsion point in extreme trim conditions was found at a lower propeller rotation rate compared to level trim conditions. This also reduced the cavitation volume and finally resulted in a delivered power reduction of up to 28.8{\%}.",
keywords = "extreme trim operation, unsteady RANSE, calm water resistance performance, automatic wake analysis, self-propulsion performance, cavitation simulation",
author = "M. Maasch and O. Turan and M. Khorasanchi and Ivy Fang",
year = "2017",
month = "9",
day = "5",
language = "English",
note = "International Conference on Shipping in Changing Climates 2017, SCC 2017 ; Conference date: 05-09-2017 Through 06-09-2017",
url = "http://www.lowcarbonshipping.co.uk/index.php?option=com_content&view=article&id=70&Itemid=188",

}

Maasch, M, Turan, O, Khorasanchi, M & Fang, I 2017, 'Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions' Paper presented at International Conference on Shipping in Changing Climates 2017, London, United Kingdom, 5/09/17 - 6/09/17, .

Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions. / Maasch, M.; Turan, O.; Khorasanchi, M.; Fang, Ivy.

2017. Paper presented at International Conference on Shipping in Changing Climates 2017, London, United Kingdom.

Research output: Contribution to conferencePaper

TY - CONF

T1 - Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions

AU - Maasch, M.

AU - Turan, O.

AU - Khorasanchi, M.

AU - Fang, Ivy

PY - 2017/9/5

Y1 - 2017/9/5

N2 - In recent years many studies and real-life applications dealing with trim optimisation have shown that operating a ship at small trim angles can improve the energy efficiency by up to 5% depending on ship speeds and loading conditions. This efficiency gain mainly results from the re-positioning of underwater hull features, such as the bulbous bow or the stern bulb. Different to the above described approach the present study deals with operating a LNG Carrier at an extreme bow-up trim angle of Ɵ = −1.9 deg. In order to predict the performance, URANS virtual towing tank simulations in calm water were performed for both, nominal resistance conditions and self-propulsion conditions including cavitation. The numerical results, including the ship resistance, the nominal propeller wake field and the simulation of propeller cavitation in self-propulsion conditions indicated a largely improved performance. Due to a significant reduction in nominal resistance by up to 27.5% the ship selfpropulsion point in extreme trim conditions was found at a lower propeller rotation rate compared to level trim conditions. This also reduced the cavitation volume and finally resulted in a delivered power reduction of up to 28.8%.

AB - In recent years many studies and real-life applications dealing with trim optimisation have shown that operating a ship at small trim angles can improve the energy efficiency by up to 5% depending on ship speeds and loading conditions. This efficiency gain mainly results from the re-positioning of underwater hull features, such as the bulbous bow or the stern bulb. Different to the above described approach the present study deals with operating a LNG Carrier at an extreme bow-up trim angle of Ɵ = −1.9 deg. In order to predict the performance, URANS virtual towing tank simulations in calm water were performed for both, nominal resistance conditions and self-propulsion conditions including cavitation. The numerical results, including the ship resistance, the nominal propeller wake field and the simulation of propeller cavitation in self-propulsion conditions indicated a largely improved performance. Due to a significant reduction in nominal resistance by up to 27.5% the ship selfpropulsion point in extreme trim conditions was found at a lower propeller rotation rate compared to level trim conditions. This also reduced the cavitation volume and finally resulted in a delivered power reduction of up to 28.8%.

KW - extreme trim operation

KW - unsteady RANSE

KW - calm water resistance performance

KW - automatic wake analysis

KW - self-propulsion performance

KW - cavitation simulation

UR - http://www.lowcarbonshipping.co.uk/index.php?option=com_content&view=article&id=70&Itemid=188

M3 - Paper

ER -

Maasch M, Turan O, Khorasanchi M, Fang I. Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions. 2017. Paper presented at International Conference on Shipping in Changing Climates 2017, London, United Kingdom.