scholarly journals INVESTIGASI ALIRAN PADA THRUSTER ROV (REMOTELY OPERATED VEHICLE) MENGGUNAKAN METODE CFD

2021 ◽  
Vol 5 (2) ◽  
pp. 371
Author(s):  
Kevin Raynaldo ◽  
Steven Darmawan ◽  
Agus Halim
Keyword(s):  
Unstructured Mesh ◽  
Open Water ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Underwater Robot ◽  
Remotely Operated Vehicle ◽  
Water Characteristics ◽  
Computational Mesh ◽  
Ansys Cfx ◽  
Blade Area

Remotely Operated Vehicle (ROV) is an underwater robot that designed by UNTAR Robotics Team and has been competed in Singapore Robotics Games (SRG) 2020. Evaluation that conducted from the competition is the need of optimization in thrust and maneuverability so it can move more flexible and stable. Based on the problem, investigation of thruster’s configuration by adding kort nozzle to existing propeller is implemented to increase thrust and performance. Consideration in using open water characteristics for analysis is elaborated in this investigation. The existing propeller has 3-blade with 35 mm diameter; 1,4 pitch diameter ratio; and 0,511 expanded blade area ratio which is used as thruster of ROV 2020. It utilizes CFD approach in ANSYS CFX 2020 R1 software with moving reference frame (MRF) method. Meanwhile, general mesh or unstructured mesh arrangements is used as computational mesh with 165.201 nodes. The MRF implements frozen rotor concept as frame change/mixing to observe fluid flow. The CFD with shear stress transport (SST) k-omega model is conducted. The simulation is done at 300 rpm and J = 0,473 for ROV’s operating condition. The result shows that thruster equipped by kort nozzle is able to increase the thrust for 2,253% and reduce the propeller required torque for 6,633%. Furthermore, the configuration can also reduce wake phenomenon as result of rotating propeller which represents better maneuver chance. Keywords: ROV, kort nozzle, open water characteristics, CFD, performanceAbstrakRemotely Operated Vehicle (ROV) merupakan sebuah underwater robot yang didesain oleh Tim Robotik UNTAR dan telah berkompetisi dalam Singapore Robotics Games (SRG) 2020. Evaluasi yang dilakukan terhadap hasil kompetisi tersebut adalah terdapat kebutuhan untuk melakukan optimasi dalam thrust dan kemampuan bermanuver sehingga ROV dapat bergerak lebih fleksibel dan stabil. Berdasarkan permasalahan tersebut, investigasi pada konfigurasi thruster dengan penambahan kort nozzle terhadap existing propeller diimplementasikan untuk meningkatkan thrust dan unjuk kerja. Pertimbangan dalam penggunaan open water characteristics sebagai dasar analisis diuraikan dalam investigasi ini. Existing propeller memiliki 3 buah blade dengan diameter 35 mm; pitch diameter ratio sebesar 1,4; dan expanded blade area ratio sebesar 0,511 yang mana digunakan sebagai thruster ROV 2020. Investigasi tersebut menggunakan pendekatan CFD dalam software ANSYS CFX 2020 R1 dengan metode moving reference frame (MRF). Sementara itu, computational mesh menggunakan jenis general mesh atau unstructured mesh arrangements dengan total 165.201 nodes. MRF mengimplementasikan konsep frozen rotor sebagai frame change/mixing untuk mengamati aliran fluida. CFD dilakukan dengan menggunakan model shear stress transport (SST) k-omega. Simulasi tersebut dilakukan pada 300 rpm dan J = 0,473 sebagai operating condition ROV. Hasil simulasi menunjukkan bahwa thruster yang dilengkapi kort nozzle mampu meningkatkan thrust sebesar 2,253% dan mengurangi torsi yang dibutuhkan propeller sebesar 6,633%. Lebih lanjut, konfigurasi ini juga dapat mengurangi fenomena wake sebagai akibat dari putaran propeller yang mana merepresentasikan peluang manuver yang lebih baik.

scholarly journals OPTIMIZATION OF B-SERIES PROPELLER DESIGN AS KCR 60 PROPULSOR TO ACHIEVE OPTIMAL PERFORMANCE USING MATHEMATICAL MODEL

JOURNAL ASRO ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 83
Author(s):  
Akhmat Nuryadin ◽  
Abdul Rahman ◽  
Cahyanto Cahyanto
Keyword(s):  
Objective Function ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Decision Variable ◽  
Propeller Design ◽  
A Value ◽  
Decision Variables ◽  
Blade Area ◽  
Calculation Results ◽  
Constraint Variable

The process of designing a propeller as a ship propulsor is an important step to produce a propeller that has the ability to achieve the desired target speed of the ship. Propeller optimization is an effort to produce a propeller design with optimal capabilities. This propeller design uses a B-series propeller where this propeller is commonly used as ship propulsor. Optimization steps to find the optimal propeller, namely: determining the objective function, determining the decision variable, and determining the constraint variable. The objective function of this optimization is to determine the Advanced-optimal (J-opt) coefficient value for the propeller. The J-opt coefficient must have a value greater than the J-Design coefficient (J-d) value and the smallest possible value (minimization function). For decision variables include picth diameter ratio (P / D) and Blade area ratio (Ae / Ao) and number of leaves (Z). While the constraint variables are: the pitch diameter ratio value of the B-series propeller (0.5≤P/D≤1.4), the blade area ratio B-series (0.3≤Ae/Ao≤1, 05) as well as the number of blade (2≤Z≤7). From the calculation results of the optimization of the B-series propeller design for the KCR 60, the optimum value is different for each blade. the propeller with the number of blade 2 (Z = 2) obtained the optimum propeller with the value of J-opt =0.77098733, Ae/Ao=0.3, P/D=1.13162337, KT = 0.165632781, 10KQ=0, 27546033 and efficiency=0.73198988. Popeller with number of blades 3 (Z=3) obtained optimum propeller with J-opt value=0.77755594, Ae/Ao=0.3, P/D=1.06370107, KT=0.168069763, 10KQ=0.28984068 and efficiency=0.70590799. Propeller with number of blades 4 (Z=4) obtained optimum propeller with J-opt value=0.78478688, Ae/Ao=0.45954773, P/D=1.03798312, Kt=0.172147709, 10Kq= 0.3091063 and efficiency=0.67797119. Propeller with blades number 5(Z=5) obtained optimum propeller with J-opt value=0.78575616, Ae/Ao=0.65607164, P/D=1.02716571, KT=0.174099168, 10KQ=0.31376705 and efficiency=0.67547177. Propeller with blades number 6 (z=6) obtained optimum propeller with J-opt value=0.78867357, Ae/Ao=0.71124343, P/D=1.0185055, KT=0.176525247, 10KQ=0.32215257 and efficiency =0.66705719. Propeller with number of blades 7 (Z=7) obtained optimum propeller with J-opt value=0.7949898, Ae/Ao=0.69772623, P/D=1.01780081, KT=0.181054792, KQ=0.34011349 , and efficiency =0.64804328.Keywords : KCR, Optimization,Wageningen B-series.

Propellers in Nozzles

1957 ◽  
Vol 1 (03) ◽  
pp. 13-46
Author(s):  
J. D. van Manen
Keyword(s):  
Area Ratio ◽  
Diameter Ratio ◽  
Nozzle Design ◽  
Nozzle Wall ◽  
Vortex System ◽  
Optimum Diameter ◽  
Blade Area ◽  
Blade Tip

The paper deals with the vortex system of the "screw + nozzle" propeller. The results obtained from systematic experiments with propellers in nozzles in which the length-diameter ratio of the nozzle, the number of blades, and the blade-area ratio of the propeller have been varied are discussed. In addition the results of experiments carried out for determining the optimum diameter of the nozzle system behind the ship are described. Explanatory comments on nozzle design are given, including diagrams for determining the radial inequality of the axial velocities in the nozzle and for making computations with regard to cavitation and strength. The influence of the clearance between blade tip and nozzle wall is discussed.

On the Optimum Wageningen B-Series Propeller Problem with Cavitation-Limiting Restraint

1979 ◽  
Vol 23 (02) ◽  
pp. 108-114
Author(s):  
P. A. Markussen
Keyword(s):  
Iterative Procedure ◽  
Open Water ◽  
Area Ratio ◽  
Simultaneous Equations ◽  
Polynomial Coefficients ◽  
Propeller Design ◽  
Blade Area ◽  
Absorbed Power ◽  
Pitch Ratio ◽  
Thrust And Torque

For the most widely encountered preliminary propeller design problem, in which absorbed power and speed of revolutions are given and the speed of advance estimated, three simultaneous equations are derived from which, using the Wageningen B-Series polynomial coefficients for propeller thrust and torque coefficients with Reynolds number corrections, the optimum blade area ratio, pitch ratio, and advance coefficient can be solved mathematically by means of an iterative procedure on a digital computer. With these variables known, the propeller particulars, thrust and torque coefficients, optimum efficiency, and open-water and cavitation characteristics can easily be calculated.

Performance Modeling of Ducted Vertical Axis Turbine Using Computational Fluid Dynamics

2013 ◽  
Vol 47 (4) ◽  
pp. 36-44 ◽  
Author(s):  
Prasun Chatterjee ◽  
Raymond N. Laoulache
Keyword(s):  
Performance Modeling ◽  
Flow Direction ◽  
Computational Cost ◽  
Vertical Axis ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Turbulent Model ◽  
Ansys Fluent ◽  
Second Order In Time ◽  
Vertical Axis Turbine

AbstractVertical axis turbines (VATs) excel over horizontal axis turbines in their independent flow direction. VATs that operate in an enclosure, e.g., a diffuser shroud, are reported to generate more power than unducted VATs. A diffuser-shrouded, high solidity of 36.67%, three-blade VAT with NACA 633-018 airfoil section is modeled in 2-D using the commercial software ANSYS-FLUENT®. Incompressible, unsteady, segregated, implicit, and second order in time and space solver is implemented in association with the Spalart-Allmaras turbulent model with a reasonable computational cost. The computational results are assessed against experimental data for unducted VAT at low tip speed ratios between 1 and 2 for further numerical analysis on diffuser models. Different diffuser designs are investigated using suitable nozzle size, area ratio, length-to-diameter ratio and angles between the diffuser inner surfaces. The numerical model shows that, for a specific diffuser design, the ducted VAT performance coefficient can be augmented by almost 90% over its unducted counterpart.

Pump Up the Volume - Massive Water Injection Increase through Open Water Stimulations

2021 ◽  
Author(s):  
Alistair Roy ◽  
Anastasia Bird ◽  
Samuel Bremner ◽  
Lara Winstone ◽  
Rustam Hashimov ◽  
...  
Keyword(s):  
Continuous Improvement ◽  
Water Injection ◽  
Open Water ◽  
High Volume ◽  
Injection Rate ◽  
Time Data ◽  
Remotely Operated Vehicle ◽  
Well Control ◽  
Pumping System ◽  
Cost Efficient

Abstract This paper describes the evolution of subsea stimulation treatments within one field including a novel dual vessel approach that was developed and successfully implemented on multiple wells. The methodology that enabled stimulations of high volume, complexity and precision is described, including observed results and opportunities for continuous improvement. In a harsh low oil price environment such cost-efficient stimulations can unlock additional potential for many subsea developments. Three West of Shetlands (WoS) injectors stimulation campaigns successfully delivered 11 subsea well treatments with a novel dual vessel batch approach in 2020 delivering operations of outstanding efficiency and reservoir results while driving costs down. A construction vessel provided remotely operated vehicle (ROV) support including deploying the well control package, whereas the stimulation vessel ran its own downline to facilitate optimized use of its dedicated pumping system and large chemical handling capacity. To enable deep water stimulation, the quick connect downline was engineered and project specific equipment installed onto the stimulation vessel allowing deployment to 450m water depth. Notable cost reductions in excess of 34% were achieved utilizing the efficiency offered by manifold entry for batch treatments to minimise the number of subsea re-connection operations while the stimulation vessel allowed much larger bulk loadouts and optimised the number of vessel loadings for continuous operations. This novel dual vessel approach for batch subsea stimulations allowed multiple well access through ‘daisy chains’ within isolated pipeline segments, while keeping injection operations live to other wells from the Glen Lyon Floating Production Storage and Offloading Vessel (FPSO) in the Schiehallion field. Improved HSE performance was achieved through reduced chemical handling and transportation. Real time data solutions for onshore monitoring were developed which aided the management of COVID-19 risks. The post-stimulation injection rate from the stimulation has signifcantly improved in all wells, resulting in large additional injection capacity for the field. Maintaining increased injection capacity has proved to be a challenge. The acquired understanding regarding water quality and longevity of treatments will allow identification of further continuous improvement opportunities to enable sustainable stimulation results.

scholarly journals Open Water Test Series of Modified AU-type Five-Bladed Propeller Models of Area Ratio 0.80

1967 ◽  
Vol 1967 (122) ◽  
pp. 77-80 ◽  
Author(s):  
Atsuo YAZAKI ◽  
Michio TAKAHASHI ◽  
Junzo MINAKATA
Keyword(s):  
Open Water ◽  
Area Ratio ◽  
Test Series ◽  
Water Test

Spring distribution, size composition and behaviour of krill Euphausia superba in the western Weddell Sea

Polar Record ◽  
1990 ◽  
Vol 26 (157) ◽  
pp. 85-89 ◽  
Author(s):  
B.I. Bergström ◽  
G. Hempel ◽  
H.-P. Marschall ◽  
A. North ◽  
V. Siegel ◽  
...  
Keyword(s):  
Algal Growth ◽  
Size Composition ◽  
Water Layer ◽  
Open Water ◽  
Euphausia Superba ◽  
Weddell Sea ◽  
Ice Algae ◽  
Remotely Operated Vehicle ◽  
Direct Observations ◽  
Pack Ice

AbstractDistribution, size composition and behaviour of Euphausia superba were investigated in the northwestern Weddell Sea (59–63°S, 45–52°W) in October-November 1988 using RMT trawling, SCUBA diving and visual examination of the ice undersurface using a remotely-operated vehicle (ROV). Amounts of krill washed onto the ice during ice-breaking along transects were noted. Juvenile and sub-adult krill were found, often in high numbers, in association with seasonal pack-ice, from the outer marginal ice zone to at least 200 nautical miles [3 50 km] into the closed pack-ice zone. Krill caught with the RMT or observed within or close to the ice usually had full guts. They were frequently seen feeding on ice algae, and seemed to concentrate in pressure zones, melting ice and infiltration layers, ie where ice provided both confining crevices and rich algal growth. During twilight numbers of krill increased in open water close to the ice, though ROV observations at night revealed even greater numbers remaining in ice cavities. Direct observations from deck, by divers and by ROV, confirmed that most of the krill population in the uppermost water layer was confined to ice habitats, though in three out of 20 RMT catches krill reached densities of 0.1 nr3 ie normal summer values. ‘Miniswarms’ forming in early November may indicate seasonal transition of at least part of the krill population from winter ice habitat and grazing on ice-algae, to summer pelagic life and filter-feeding on phytoplankton.

Experimental and Numerical Investigation of DARPA Suboff Submarine Propelled with INSEAN E1619 Propeller for Self-Propulsion

2019 ◽  
Vol 63 (4) ◽  
pp. 235-250
Author(s):  
Yasemin Arıkan Özden ◽  
Münir Cansın Özden ◽  
Ersin Demir ◽  
Sertaç Kurdoğlu
Keyword(s):  
Open Water ◽  
Test Method ◽  
The Self ◽  
Propulsive Efficiency ◽  
Ship Model ◽  
Rotation Rates ◽  
Water Characteristics ◽  
Numerical Studies ◽  
Computational Fluid Dynamics Cfd ◽  
Thrust And Torque

The Defense Advanced Research Projects Agency (DARPA) Suboff Submarine propelled by the Italian Ship Model Basin (INSEAN) E1619 propeller is extensively used in submarine validation studies. Although there are several numerical studies where the DARPA Suboff submarine is used in combination with E1619 propeller there are no experimental data available in open literature for the self-propulsion condition. In this article, the self-propulsion characteristics of the DARPA Suboff submarine model with INSEAN E1619 propeller obtained with experimental and numerical methods are presented and discussed by means of Taylor wake fraction, thrust deduction, hull efficiency, relative rotative efficiency, and propulsive efficiency. To experimentally investigate the submarine form, a self-propulsion experimental setup is designed and manufactured. Resistance and self-propulsion experiments are conducted in Istanbul Technical University Ata Nutku Ship Model Testing Laboratory. Resistance tests are carried out for three different speeds, and the results show good agreement with the published experimental results. Propulsion tests are conducted by using the load-varying self-propulsion test method for constant speed and seven different propeller rotation rates. Rotational speed, thrust, and torque forces at self-propulsion point are investigated. For the numerical computations a commercial Computational Fluid Dynamics (CFD) code is used. Propeller open water characteristics and nondimensional velocities behind the propeller are calculated. Self-propulsion point of the submarine and propeller assembly is also solved numerically and the results are compared with the results obtained from the experiments, and it is seen that especially the propeller rate of revolution and thrust force are predicted with very good approximation.

The Weddell Sea Expedition 2019

2020 ◽  
Author(s):  
John Shears ◽  
Julian Dowdeswell ◽  
Freddie Ligthelm ◽  
Paul Wachter
Keyword(s):  
Sea Ice ◽  
Autonomous Underwater Vehicles ◽  
Remote Sensing Data ◽  
Open Water ◽  
Weddell Sea ◽  
Scientific Programme ◽  
Ice Shelf ◽  
Remotely Operated Vehicle ◽  
Radar Images ◽  
Ice Conditions

<p>The Weddell Sea Expedition 2019 (WSE) was conceived with dual aims: (i) to undertake a comprehensive international inter-disciplinary programme of science centred in the waters around Larsen C Ice Shelf, western Weddell Sea; and (ii) to search for, survey and image the wreck of Sir Ernest Shackleton’s Endurance, which sank in the Weddell Sea in 1915. </p><p>The 6-week long expedition, funded by the Flotilla Foundation, required the use of a substantial ice-strengthened vessel given the very difficult sea-ice conditions encountered in the Weddell Sea, and especially in its central and western parts. The South African ship SA Agulhas II was chartered for its Polar Class 5 icebreaking capability and design as a scientific research vessel. The expedition was equipped with state-of-the-art Autonomous Underwater Vehicles (AUVs) and a Remotely Operated Vehicle (ROV) which were capable of deployment to waters more than 3,000 m deep, thus making the Larsen C continental shelf and slope, and the Endurance wreck site, accessible. During the expedition, a suite of passive and active remote-sensing data, including TerraSAR-X radar images delivered in near real-time, was provided to the ice-pilot onboard the SA Agulhas II. These data were instrumental for safe vessel navigation in sea ice and the detection and tracking of icebergs and ice floes of scientific interest.</p><p>The scientific programme undertaken by the WSE was very successful and produced many new geological, geophysical, marine biological and oceanographic observations from a part of the Weddell Sea that has been little studied previously, particularly the area east of Larsen C Ice Shelf. The expedition also reached the sinking location of Shackleton’s Endurance, where the presence of open-water sea ice leads allowed the deployment of an AUV to the ocean floor to try and locate and survey the wreck. Unfortunately, SA Agulhas II later lost communication with the AUV, and deteriorating weather and sea ice conditions meant that the search had to be called off.</p>

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