Numerical Prediction of Model Podded Propeller-Ice Interaction Loads

2006 ◽  
Author(s):  
Jungyong Wang ◽  
Ayhan Akinturk ◽  
Neil Bose
Keyword(s):  
Prediction Model ◽  
National Research Council ◽  
Model Tests ◽  
Numerical Prediction ◽  
Panel Method ◽  
Operating Conditions ◽  
Propeller Blade ◽  
Hydrodynamic Loads ◽  
Hydrodynamic Calculations ◽  
Ice Loads

As the interest in arctic shipping and arctic exploration of oil and gas is increasing in recent years, the number of ice class vessels is increasing rapidly. Also the choices for propulsion devices are getting wider and these include podded propulsion systems. This study is a framework for the numerical prediction of the ice interaction loads acting on a podded propeller blade. The results of this study will help us to understand the propeller-ice interaction problem more comprehensively. Several studies for propeller-ice interaction have been carried out in the past few decades. Propeller-ice interaction, however, is a complicated process with a high level of uncertainties due to ice properties, ship operating conditions, and environmental conditions. Full-scale measurements involve high costs. In order to overcome these difficulties, model tests were carried out with model ice in an ice tank. The model tests provide well-controlled ice properties and interaction conditions to reduce the uncertainties. The tests were carried out in the ice tank with scaled down model ice at the National Research Council of Canada’s Institute for Ocean Technology. The ice loads acting on the propeller blade were measured with a six-component force and moment load cell fitted to the shaft and one of the propeller blades. Based on the experimental results, a numerical prediction model was developed to estimate the ice loads on the propeller blade. The numerical prediction is composed of three parts: the hydrodynamic calculations including separable and inseparable hydrodynamic loads, and the ice milling loads calculation. The separable and inseparable hydrodynamic loads can be obtained from clear water and blocked flow respectively. The hydrodynamic calculations were done by a low order panel method. The subroutines for calculating the ice milling loads are implemented into the panel method. The numerical prediction model for ice milling loads is described and the results are compared with those of experiments.

Numerical Prediction of Propeller Performance During Propeller-Ice Interaction

2009 ◽  
Vol 46 (03) ◽  
pp. 123-139
Author(s):  
Jungyong Wang ◽  
Ayhan Akinturk ◽  
Neil Bose
Keyword(s):  
Prediction Model ◽  
Empirical Model ◽  
Empirical Formula ◽  
Numerical Prediction ◽  
Experimental Results ◽  
Hydrodynamic Load ◽  
Propeller Blade ◽  
Hydrodynamic Loads ◽  
Ice Loads ◽  
Propeller Performance

The aim of the present study was to predict propeller performance during propeller-ice interaction. Total loads acting on a propeller blade during propeller-ice interaction were assumed to consist of three major components: separable hydrodynamic loads, inseparable hydrodynamic loads, and ice milling loads. A panel method and an empirical formula were used for the hydrodynamic load calculations and the ice contact load calculations, respectively. This empirical model was implemented into a numerical panel code. The numerical prediction model for the ice loads including the detailed implementation is described, and the results are compared with experimental results.

Ice Loads on a Model Podded Propeller Blade in Milling Conditions

2005 ◽  
Author(s):  
Jungyong Wang ◽  
Ayhan Akinturk ◽  
Stephen J. Jones ◽  
Neil Bose
Keyword(s):  
Research Council ◽  
National Research Council ◽  
Propeller Blade ◽  
Hydrodynamic Loads ◽  
Ice Loads ◽  
Advance Ratio

Propeller-ice interaction experiments were conducted in the ice tank at the National Research Council of Canada’s Institute for Ocean Technology. A podded propeller was used in “Puller” mode and loads on an instrumented blade were measured. During the propeller-ice interaction, hydrodynamic loads and ice milling loads were acting on the propeller blade. This paper focuses on the ice milling loads both in water and in air. The ice milling loads, however, cannot be separated from the hydrodynamic loads perfectly. Even if the blade is milling the ice within an ice block, it is still experiencing hydrodynamic loads designated as inseparable hydrodynamic loads. The non-dimensional ice milling loads including inseparable hydrodynamic loads on the blade are presented against advance ratio with varied depths of cut. The results help to reduce the gap of knowledge for interaction between ice and propeller and give information about significant variables acting on the propeller blade during interaction.

Prediction model of flow field in an isolator over various operating conditions

2021 ◽  
Vol 111 ◽  
pp. 106576
Author(s):  
Chen Kong ◽  
Juntao Chang ◽  
Ziao Wang ◽  
Yunfei Li
Keyword(s):  
Flow Field ◽  
Prediction Model ◽  
Operating Conditions

Advanced Weathervaning in Ice

2011 ◽  
Author(s):  
William Hidding ◽  
Guillaume Bonnaffoux ◽  
Mamoun Naciri
Keyword(s):  
Rapid Change ◽  
Ice Sheet ◽  
Model Tests ◽  
The Arctic ◽  
Mooring System ◽  
Sudden Increase ◽  
Time Step ◽  
Ice Loads ◽  
Level Ice ◽  
Drift Direction

The reported presence of one third of remaining fossil reserves in the Arctic has sparked a lot of interest from energy companies. This has raised the necessity of developing specific engineering tools to design safely and accurately arctic-compliant offshore structures. The mooring system design of a turret-moored vessel in ice-infested waters is a clear example of such a key engineering tool. In the arctic region, a turret-moored vessel shall be designed to face many ice features: level ice, ice ridges or even icebergs. Regarding specifically level ice, a turret-moored vessel will tend to align her heading (to weather vane) with the ice sheet drift direction in order to decrease the mooring loads applied by this ice sheet. For a vessel already embedded in an ice sheet, a rapid change in the ice drift direction will suddenly increase the ice loads before the weathervaning occurs. This sudden increase in mooring loads may be a governing event for the turret-mooring system and should therefore be understood and simulated properly to ensure a safe design. The paper presents ADWICE (Advanced Weathervaning in ICE), an engineering tool dedicated to the calculation of the weathervaning of ship-shaped vessels in level ice. In ADWICE, the ice load formulation relies on the Croasdale model. Ice loads are calculated and applied to the vessel quasi-statically at each time step. The software also updates the hull waterline contour at each time step in order to calculate precisely the locations of contact between the hull and the ice sheet. Model tests of a turret-moored vessel have been performed in an ice basin. Validation of the simulated response is performed by comparison with model tests results in terms of weathervaning time, maximum mooring loads, and vessel motions.

Experimental and Analytical Characterization of Alternative Aviation Fuel Sprays Under Realistic Operating Conditions

2018 ◽  
Author(s):  
Andrew Corber ◽  
Nader Rizk ◽  
Wajid Ali Chishty
Keyword(s):  
Experimental Data ◽  
Alternative Fuels ◽  
Laser Sheet ◽  
National Research Council ◽  
Diagnostic System ◽  
Operating Conditions ◽  
Aviation Fuel ◽  
Injection System ◽  
Test Time

The National Jet Fuel Combustion Program (NJFCP) is an initiative, currently being led by the Office of Environment & Energy at the FAA, to streamline the ASTM jet fuels certification process for alternative aviation fuels. In order to accomplish this objective, the program has identified specific applied research tasks in several areas. The National Research Council of Canada (NRC) is contributing to the NJFCP in the areas of sprays and atomization and high altitude engine performance. This paper describes work pertaining to atomization tests using a reference injection system. The work involves characterization of the injection nozzle, comparison of sprays and atomization quality of various conventional and alternative fuels, as well as use of the experimental data to validate spray correlations. The paper also briefly explores the application viability of a new spray diagnostic system that has potential to reduce test time in characterizing sprays. Measurements were made from ambient up to 10 bar pressures in NRC’s High Pressure Spray Facility using optical diagnostics including laser diffraction, phase Doppler anemometry (PDA), LIF/Mie Imaging and laser sheet imaging to assess differences in the atomization characteristics of the test fuels. A total of nine test fluids including six NJFCP fuels and three calibration fluids were used. The experimental data was then used to validate semi-empirical models, developed through years of experience by engine OEMs and modified under NJFCP, for predicting droplet size and distribution. The work offers effective tools for developing advanced fuel injectors, and generating data that can be used to significantly enhance multi-dimensional combustor simulation capabilities.

A Nitrogen Oxides Emission Prediction Model for Gas Turbines Based on Interpretable Multilayer Perceptron Neural Networks

2020 ◽  
Author(s):  
Dawen Huang ◽  
Shanhua Tang ◽  
Dengji Zhou
Keyword(s):  
Neural Networks ◽  
Nitrogen Oxides ◽  
Prediction Model ◽  
Working Conditions ◽  
Gas Turbines ◽  
Middle Layer ◽  
Operating Conditions ◽  
Nox Emission ◽  
Outlet Temperature ◽  
Output Layer

Abstract Gas turbines, an important energy conversion equipment, produce Nitrogen Oxides (NOx) emissions, endangering human health and forming air pollution. With the increasingly stringent NOx emission standards, it is more significant to ascertain NOx emission characteristics to reduce pollutant emissions. Establishing an emission prediction model is an effective way for real-time and accurate monitoring of the NOx discharge amount. Based on the multi-layer perceptron neural networks, an interpretable emission prediction model with a monitorable middle layer is designed to monitor NOx emission by taking the ambient parameters and boundary parameters as the network inputs. The outlet temperature of the compressor is selected as the monitorable measuring parameters of the middle layer. The emission prediction model is trained by historical operation data under different working conditions. According to the errors between the predicted values and measured values of the middle layer and output layer, the weights of the emission prediction model are optimized by the back-propagation algorithm, and the optimal NOx emission prediction model is established for gas turbines under the various working conditions. Furthermore, the mechanism of predicting NOx emission value is explained based on known parameter influence laws between the input layer, middle layer and output layer, which helps to reveal the main measurement parameters affecting NOx emission value, adjust the model parameters and obtain more accurate prediction results. Compared with the traditional emission monitoring methods, the emission prediction model has higher accuracy and faster calculation efficiency and can obtain believable NOx emission prediction results for various operating conditions of gas turbines.

The Ocean Cleanup System 001 Performance During Towing and Seakeeping Tests

2019 ◽  
Author(s):  
Joost Sterenborg ◽  
Nicola Grasso ◽  
Rogier Schouten ◽  
Arjen Tjallema
Keyword(s):  
Fluid Structure Interaction ◽  
Model Tests ◽  
Operating Conditions ◽  
Image Correlation ◽  
Plastic Pollution ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Floating System ◽  
Floating Systems

Abstract One of the aims of The Ocean Cleanup is to develop technologies to extract plastic pollution from the world’s oceans. Several concepts of passive floating systems were considered that are supposed to confine plastics to ease their collection. Such concepts consist of a floating member and a submerged flexible skirt and have in common that their span is generally more than 500 meters. Consequently, fluid-structure interaction plays an important role in the response of such a floating system. To support numerical simulations, MARIN carried out extensive model tests on a 120 meter system section of the final concept, with focus on the fluid-structure interaction (FSI) of the submerged skirt in operating conditions and in towing configuration. The ability to capture plastics was not investigated in these model tests. Novel for wave-basin tests were non-intrusive measurements using underwater Digital Image Correlation (DIC) to obtain the displacements and deformations of the flexible skirt. DIC proved to be a capable measurement technique for this type of structure in combination with a wave basin. Detailed quantitative data on skirt motions and deformations were delivered and the last concept of the cleanup system was tested in the towing configuration and operational configuration.

scholarly journals Improvement of the Efficiency of the Axial-Flow Pump at Part Loads due to Installing Outlet Guide Vanes Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Fan Yang ◽  
Hao-ru Zhao ◽  
Chao Liu
Keyword(s):  
Prediction Model ◽  
Flow Rate ◽  
High Efficiency ◽  
Guide Vane ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Ann Model ◽  
Axial Flow Pump ◽  
Flow Pump

In order to investigate the influence of adjustable outlet guide vane on the hydraulic performance of axial-flow pump at part loads, the axial-flow pump with 7 different outlet guide vane adjustable angles was simulated based on the RNG k-ε turbulent model and Reynolds time-averaged equations. The Vector graphs of airfoil flow were analyzed in the different operating conditions for different adjustable angles of guide vane. BP-ANN prediction model was established about the effect of adjustable outlet guide vane on the hydraulic performance of axial-flow pump based on the numerical results. The effectiveness of prediction model was verified by theoretical analysis and numerical simulation. The results show that, with the adjustable angle of guide vane increasing along clockwise, the high efficiency area moves to the large flow rate direction; otherwise, that moves to the small flow rate direction. The internal flow field of guide vane is improved by adjusting angle, and the flow separation of tail and guide vane inlet ledge are decreased or eliminated, so that the hydraulic efficiency of pumping system will be improved. The prediction accuracy of BP-ANN model is 1%, which can meet the requirement of practical engineering.

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