Full Scale Dynamic Propulsion Shaft Alignment Investigation

2012 ◽  
Author(s):  
Arie D. Leeuwenburg ◽  
B. Hooghart
Keyword(s):  
Full Scale ◽  
Bending Stress ◽  
Monitoring Tool ◽  
Operational Conditions ◽  
Sea Trial ◽  
Shaft Line ◽  
Bearing Load ◽  
Shaft Alignment ◽  
Recorded Data ◽  
Shaft Torque

SKF Marine ISC was requested by STX Finland Oy, location Rauma to perform full scale dynamic propulsion shaft measurements on board of the RoPax vessel “Pride of France” in order to solve high shaft support bearing operational temperatures. After modeling the propulsion line with a state-of-the-art CAE software for shaft alignment and vibration calculations and recording of the actual static bearing load and actual static bending stress of the accessible shaft line, during a sea trial, several dynamic measurements like dynamic bending stress, shaft torque and speed, shaft orbit, bearing temperature, vibration and longitudinal shaft movement were measured and recorded. After analysis of the measured and recorded data, following conclusions could be made; Large longitudinal shafts movements were present in operational condition. Measured shaft support bearing temperatures have a linear relationship with measured and calculated bearing load in operational condition, so temperature readings can be used as a condition monitoring tool to calculate bearing load in different operational conditions.

Smart Bearing Sensor

2020 ◽  
Vol 36 (01) ◽  
pp. 67-77
Author(s):  
Chris Leontopoulos ◽  
Charalampos Mouzakis ◽  
Michail Petrolekas
Keyword(s):  
Future Application ◽  
Misalignment Angle ◽  
Widespread Application ◽  
Operational Conditions ◽  
Verification Method ◽  
Bearing Load ◽  
Undesirable Consequence ◽  
Shaft Alignment ◽  
Energy Efficiency Design Index ◽  
Jack Up

The recent increase in vessel shaftline bearing incidents indicates that a static shaft alignment design may not be suitable for all operational shaftline loading conditions. Hull deflections caused by vessel loading or propeller loads initiated by interaction with the wakefield have become important considerations in modern vessel design. Jack-up tests, typically used as a bearing load verification method, can only be accomplished under static shaft conditions and cannot verify the shaft dynamic behavior under running operational conditions. A newly developed sensor using strain gauge technology measures the bearing load and the shaft misalignment angle through the bearing housing's deformation-induced strain. It effectively converts the bearing housing into a weighing machine by mapping the bearing housing strain onto the bearing load. Unlike jack-up tests, this method allows for the continuous measurement of the bearing load and misalignment angle under all shaftline operational conditions. It is envisaged that this technologically simple system will allow for the earliest possible diagnosis of shaft alignment-related problems, such as bearing unloading, bearing overloading, or excessive shaft-bearing misalignment. This provides a much earlier warning indicator when compared with the bearing temperature alarm. The subject technology has been tested on intermediate bearings and is considered for future application into stern tube bearings. 1. Introduction In post-IMO's (International Maritime Organization) Energy Efficiency Design Index vessel designs, the propulsion shafting arrangements become increasingly sensitive to shaft alignment with lower tolerances and margins, increasing the risk of stern tube bearing failures (Leontopoulos 2016a). This change is due to the wider use of more efficient, larger diameter propellers with increased cantilevered load on the shafting system and shorter shaftlines as a result of maximizing cargo space and minimizing engine room length. Widespread application of the single stern tube bearing design (an arrangement without a forward stern tube bearing) has also highlighted a decreased tolerance to eccentric propeller thrust and propeller forces in general. Reduced tolerance to shaft alignment sighting errors, bearing offset inaccuracies and other shaft installation errors, also affects the integrity of the shafting system and can result in complete bearing wiping with the consequence of vessel propulsion immobilization. This undesirable consequence has increased, particularly during the years 2013–2017.

Shaft alignment of large LNG carrier with twin screw propulsion

2015 ◽  
Author(s):  
Liu Tao
Keyword(s):  
Fluid Dynamic ◽  
Propulsion System ◽  
Vertical Position ◽  
Fe Model ◽  
Loading Conditions ◽  
Operational Conditions ◽  
Shaft Line ◽  
Hull Structure ◽  
Twin Screw ◽  
Shaft Alignment

Optimized shaft alignment and high-quality construction are important guarantee of safe operation for propulsion system on board. Twin-propulsion system arrangement with certain degree skeg is more and more adopted by large LNG carrier. The global FE model with local refined mesh was used to capture the deflection of the hull structure around the propeller shaft system under different draft and loading conditions. Propeller forces were analyzed by computational fluid dynamic under severe operational conditions. Ship hull deformation and propeller forces were considered during the shaft line alignment calculations. In shaft line alignment calculation, there were five static loading conditions and six dynamic loading conditions. Following an iterative procedure in DNV shaft alignment software, the vertical position of all bearings relative to reference line was obtained in all calculated loading conditions. A stern tube bearing monitoring system was installed to monitor alignment performance in real time.

A Comparison of Inverse Models for the Estimation of Ice-Induced Propeller Moments on a Polar Vessel

2021 ◽  
Author(s):  
Brendon M. Nickerson ◽  
Anriëtte Bekker
Keyword(s):  
Rotational Speed ◽  
Continuous Model ◽  
Full Scale ◽  
Lumped Mass ◽  
Mass Model ◽  
Inverse Models ◽  
Lumped Mass Model ◽  
Ill Posed ◽  
Shaft Torque ◽  
Measurement Location

Abstract Full-scale measurements were conducted on the port side propulsion shaft the S.A. Agulhas II during the 2019 SCALE Spring Cruise. The measurements included the shaft torque captured at two separate measurement locations, and the shaft rotational speed at one measurement location. The ice-induced propeller moments are estimated from the full-scale shaft responses using two inverse models. The first is a published discrete lumped mass model that relies on regularization due to the inverse problem being ill-posed. This model is only able to make use of the propulsion shaft torque as inputs. The second model is new and employs modal superposition to represent the propulsion shaft as a combination of continuous modes, resulting in a well-posed problem. This new model requires the additional measurement of the shaft rotational speed for the inverse solution. The continuous model is shown to be more consistent and efficient, which allows its use in real-time monitoring of propeller moments.

Improvements in Data Acquisition for Propulsion Shaft Alignment

2015 ◽  
Author(s):  
W. David Joiner ◽  
Charles J. Cook
Keyword(s):  
Data Acquisition ◽  
Strain Gage ◽  
Strain Gages ◽  
Construction Process ◽  
Crucial Step ◽  
Ship Construction ◽  
Shaft Line ◽  
Load Cells ◽  
Shaft Alignment

Propulsion shaft alignment is a necessary and crucial step in the ship construction process, with manning and schedule constraints requiring accurate results as efficiently as possible. There are two methods for measuring the bearing loading along the shaft line: strain gages and load cells. The legacy method for using strain gages required a lot of man power and the legacy method for using load cells was dependent on the quality of machinist made available. Strain gages are the transducers of choice for measurement; however the data acquisition, especially for ships with long shafting systems, can require many strain gage positions and personnel to conduct tests. Load cells are used to validate the accuracy of the strain gage method and to calculate the shaft runout at each bearing location.

scholarly journals Niche Differentiation among Three Closely RelatedCompetibacteraceaeClades at a Full-Scale Activated Sludge Wastewater Treatment Plant and Putative Linkages to Process Performance

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Veronica R. Brand ◽  
Laurel D. Crosby ◽  
Craig S. Criddle
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Niche Differentiation ◽  
Full Scale ◽  
Pure Oxygen ◽  
Operational Parameters ◽  
Metabolic Potential ◽  
Operational Conditions

ABSTRACTMultiple clades within a microbial taxon often coexist within natural and engineered environments. Because closely related clades have similar metabolic potential, it is unclear how diversity is sustained and what factors drive niche differentiation. In this study, we retrieved three near-complete Competibacter lineage genomes from activated sludge metagenomes at a full-scale pure oxygen activated sludge wastewater treatment plant. The three genomes represent unique taxa within theCompetibacteraceae. A comparison of the genomes revealed differences in capacity for exopolysaccharide (EPS) biosynthesis, glucose fermentation to lactate, and motility. Using quantitative PCR (qPCR), we monitored these clades over a 2-year period. The clade possessing genes for motility and lacking genes for EPS biosynthesis (CPB_P15) was dominant during periods of suspended solids in the effluent. Further analysis of operational parameters indicate that the dominance of the CPB_P15 clade is associated with low-return activated sludge recycle rates and low wasting rates, conditions that maintain relatively high levels of biomass within the system.IMPORTANCEMembers of the Competibacter lineage are relevant in biotechnology as glycogen-accumulating organisms (GAOs). Here, we document the presence of threeCompetibacteraceaeclades in a full-scale activated sludge wastewater treatment plant and their linkage to specific operational conditions. We find evidence for niche differentiation among the three clades with temporal variability in clade dominance that correlates with operational changes at the treatment plant. Specifically, we observe episodic dominance of a likely motile clade during periods of elevated effluent turbidity, as well as episodic dominance of closely related nonmotile clades that likely enhance floc formation during periods of low effluent turbidity.

Numerical Investigation of Energy Saving Device Effects on Ships With Propeller-Hull Interactions

2018 ◽  
Author(s):  
Ravi Chaithanya Mysa ◽  
Le Quang Tuyen ◽  
Ma Shengwei ◽  
Vinh-Tan Nguyen
Keyword(s):  
Energy Saving ◽  
Full Scale ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Propulsion Efficiency ◽  
Operational Conditions ◽  
Ship Resistance ◽  
The Past ◽  
Eddy Simulation ◽  
Flow Features

Energy saving devices (ESD) such as propeller ducts, pre-swirl stators, pre-nozzles, etc have been explored as a more economic and reliable approach to reduce energy consumption for both in-operation and newly design ships over the past decades. Those energy saving devices work in the principle of reducing ship resistance and improving propulsion efficiency as well as hull-propeller interactions. Potential saving from various types of ESD have been reported in literature from the range of 3–9% [1] for propulsion efficiency dependent on different measures. Deployment of those devices on actual full-scale ships has been limited over the past years. One of the key obstacles in application of ESD is the lack of confidence in measuring its efficiency on full-scale ships in actual operational conditions. Advances in computational fluid dynamics (CFD) has provided an alternative approach from model scale test to better understand uncertainties in prediction of ESD efficiency in full-scale ship operations [Shin et al, 2013]. In this work a high fidelity CFD model is presented for investigation effects of pre-nozzles on propulsion efficiency and ship resistance. The model is based on the Reynolds Average Navier-Stokes (RANS) solver with different turbulent models including a hybrid detached eddy simulation (DES) approach for predictions of complex near body flow features as well as in the wake regions from hull and propeller. The model is validated with model test for both towing and self-propulsion conditions. Finally a study of pre-nozzle effects on propeller efficiency as well as hull-propeller interaction is presented and compared with available experimental data (Tokyo 2015 Workshop). The current work constitutes a fundamental approach towards designing more efficient ESD for a specific hull form and propeller.

Pressure Measurements on Yacht Sails: Development of a new system for wind tunnel and full scale testing

2016 ◽  
Author(s):  
Fabio Fossati ◽  
Ilmas Bayati ◽  
Sara Muggiasca ◽  
Ambra Vandone ◽  
Gabriele Campanardi ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Unsteady Aerodynamics ◽  
Research Field ◽  
Full Scale ◽  
Measuring System ◽  
Windward Side ◽  
Pressure System ◽  
Operational Conditions ◽  
Sailing Yacht ◽  
Full Scale Testing

The paper presents an overview of a joint project developed among Politecnico di Milano, CSEM and North Sails, aiming at developing a new sail pressure measurement system based on MEMS sensors (an excellent compromise between size, performance, costs and operational conditions) and pressure strips and pads technology. These devices were designed and produced to give differential measurement between the leeward and windward side of the sails. The project has been developed within the Lecco Innovation Hub Sailing Yacht Lab, a 10 m length sailing dynamometer which intend to be the reference contemporary full scale measurement device in the sailing yacht engineering research field, to enhance the insight of sail steady and unsteady aerodynamics [1]. The pressure system is described in details as well as the data acquisition process and system metrological validation is provided; furthermore, some results obtained during a wind tunnel campaign carried out at Politecnico di Milano Wind Tunnel, as a benchmark of the whole measuring system for future full scale application, are reported and discussed in details. Moreover, the system configuration for full scale testing, which is still under development, is also described.

A Discussion on recent research in air pollution - Plume rise estimates for electric generating stations

1969 ◽  
Vol 265 (1161) ◽  
pp. 221-243 ◽  
Keyword(s):  
Air Pollution ◽  
Pollution Control ◽  
Full Scale ◽  
Plume Rise ◽  
Air Pollution Control ◽  
Operational Conditions ◽  
The Public ◽  
Wide Range ◽  
Tennessee Valley ◽  
Comprehensive Study

The Tennessee Valley Authority, under sponsorship of the Public Health Service, National Air Pollution Control Administration, initiated a comprehensive study titled ‘ Full scale study of plume rise at large electric generating stations’ in 1963. The variability of plant sizes, stack heights, and stack configurations accommodated full scale assessment of plume rise over a wide range of meteorological and operational conditions.

THD Analysis in Tilting-Pad Journal Bearings Using Multiple Orifice Hybrid Lubrication

1999 ◽  
Vol 121 (4) ◽  
pp. 892-900 ◽  
Author(s):  
I. F. Santos ◽  
R. Nicoletti
Keyword(s):  
Load Capacity ◽  
Flow Behavior ◽  
Journal Bearings ◽  
Operational Conditions ◽  
Tilting Pad ◽  
Bearing Load ◽  
Cooling Effects ◽  
Experimental Values ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

Tilting pad journal bearings (TPJB) using multiple orifice hybrid lubrication are analyzed applying a thermohydrodynamic (THD) theory. Adiabatic boundary conditions are adopted, and a two-dimensional model is used to represent the fluid flow behavior in the bearing gap. The influence of operational conditions on the temperature distribution and on the bearing load capacity is discussed and compared to theoretical and experimental values for a conventional hydrodynamic case (without radial oil injection). To improve the cooling effects, as well as rotor attitudes, the best location for orifices is the area near the pad edges.

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