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.

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.

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.

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.

scholarly journals Blade Tip-Vortices of a Four-Bladed Rotor with Axial Inflow

2020 ◽  
Vol 65 (4) ◽  
pp. 1-13
Author(s):  
Andreas Goerttler ◽  
Johannes N. Braukmann ◽  
C. Christian Wolf ◽  
Anthony D. Gardner ◽  
Markus Raffel
Keyword(s):  
Particle Image ◽  
Test Facility ◽  
Vortex System ◽  
Tip Vortices ◽  
Image Velocimetry ◽  
Swirl Velocity ◽  
Blade Tip ◽  
Velocity Circulation ◽  
Bladed Rotor ◽  
German Aerospace

The vortex system of four rotating and pitching DSA-9A blades was examined numerically and experimentally. Numerical computations were performed using German Aerospace Center (DLR)'s finite-volume solver TAU and were validated against experimental data gathered using particle image velocimetry carried out at the rotor test facility (RTG) in Göttingen. Algorithms deriving the vortex position, swirl velocity, circulation, and core radius were implemented. Hover-like conditions with a fixed blade pitch were analyzed giving further physical insights of the static vortex system. These results are used to understand the vortex development for the unsteady pitching conditions, which can be described as a superpositioning of static vortex states. The use of a zonal detached-eddy simulations approach improved physical modeling of the vortex development by resolving finer scales than URANS. Trimmed cases agree well with differences less than 0.5% in the circulation and swirl velocity.

scholarly journals Allometry and morphophysiology of papaya seedlings in a substrate with polymer under irrigation with saline water

2020 ◽  
Vol 11 ◽  
pp. e3339
Author(s):  
EXPEDITO CAVALCANTE NASCIMENTO NETO ◽  
Francisco Thiago Coelho Bezerra ◽  
Marlene Alexandrina Ferreira Bezerra ◽  
Walter Esfrain Pereira ◽  
Lourival Ferreira Cavalcante ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Leaf Area ◽  
Irrigation Water ◽  
Saline Water ◽  
Block Design ◽  
Dry Mass ◽  
Area Ratio ◽  
Irrigation Frequency ◽  
Randomized Block Design ◽  
Blade Area

The availability and quality of the irrigation water are among the limitations for the development of agriculture in the semiarid. Aiming at gathering information on these limitations, this work aimed to evaluate the association between a water-absorbing polymer and water salinity in irrigation frequencies, as well as container volumes on the allometric and morphophysiological indices of seedlings of the papaya (Carica papaya) cultivar ‘Sunrise Solo’. The treatments were obtained from the combination between the water-absorbing polymer (0.0; 0.2; 0.6; 1.0, and; 1.2 g dm-3), the electrical conductivity of the irrigation water (0.3; 1.1; 2.7; 4.3, and; 5.0 dS m-1), and irrigation frequencies (daily and alternate), plus two additional treatments (0.75 and 1.30 dm3) to study the effects of the container volume, distributed in a randomized block design. At 55 days after sowing, the following characteristics were evaluated: ratio between stem height and diameter; ratio between shoot and root dry matter; root density; leaf blade area; ratio between total leaf area and root dry mass; specific leaf area; leaf area ratio; leaf mass ratio; and Dickson quality index. The allometric and morphophysiological indices were damaged by the increase of water electrical conductivity and favored by the application of the polymer and a higher irrigation frequency. In the production of papaya seedlings, a daily irrigation frequency must be prioritized, using containers of 0.75 or 1.30 dm-3, water with electrical conductivity up to 2.6 and 1.9 dS m-1 when irrigated daily or in alternate days, respectively, and 0.6 g dm-3 of polymer.

Performance Prediction of Newton-Rader Propellers

2008 ◽  
Vol 52 (02) ◽  
pp. 124-145
Author(s):  
Yin L. Young ◽  
Zhanke Liu
Keyword(s):  
Numerical Method ◽  
Performance Prediction ◽  
High Speed ◽  
High Efficiency ◽  
Area Ratio ◽  
Structural Performance ◽  
Experimental Measurements ◽  
Cavitation Tunnel ◽  
Blade Area ◽  
Hydroelastic Analysis

In this work, a numerical method is presented for the hydrodynamic and hydroelastic analysis of Newton-Rader (NR) propellers (Newton & Rader 1961). The NR propellers are a well-known series of three-bladed propellers specifically designed, extensively tested, and well documented for high-speed crafts. The tests were conducted at the Vosper Cavitation Tunnel, and the propellers exhibit both face and back cavitation patterns (Newton & Rader 1961). The predicted fully wetted and cavitating performance agreed well with experimental measurements. The results indicate that the NR propellers can achieve high efficiency in both the fully wetted and cavitating regimes if the blades exhibit only back cavitation. However, significant reduction in efficiency was observed in all cases when face cavitation develops. The effects of varying blade area ratio on the hydrodynamic and structural performance are discussed. The importance of hydroelastic effects for both model-scale and full-scale NR propellers in uniform and wake inflow are presented.

Blade Tip Vortex System of a Rotor with Cyclic Pitch

AIAA Journal ◽  
2020 ◽  
Vol 58 (7) ◽  
pp. 2869-2880
Author(s):  
Johannes N. Braukmann ◽  
C. Christian Wolf ◽  
Andreas Goerttler ◽  
Markus Raffel
Keyword(s):  
Tip Vortex ◽  
Vortex System ◽  
Blade Tip

Cavitation Inception and Head Loss Due to Liquid Flow Through Perforated Plates of Varying Thickness

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
D. Maynes ◽  
G. J. Holt ◽  
J. Blotter
Keyword(s):  
Plate Thickness ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Hole Diameter ◽  
Loss Coefficient ◽  
Perforated Plates ◽  
Cavitation Inception ◽  
Perforation Hole ◽  
Critical Cavitation ◽  
Free Area

This paper reports results of an experimental investigation of the loss coefficient and onset of cavitation caused by water flow through perforated plates of varying thickness and flow area to pipe area ratio at high speeds. The overall plate loss coefficient, point of cavitation inception, and point where critical cavitation occurs are functions of perforation hole size, number of holes, and plate thickness. Sixteen total plates were considered in the study with the total perforation hole area to pipe area ratio ranging from 0.11 and 0.6, the plate thickness to perforation hole diameter ranging from 0.25 to 3.3, and the number of perforation holes ranging from 4 to 1800. The plates were mounted in the test section of a closed water flow loop. The results reveal a complex dependency between the plate loss coefficient with total free-area ratio and the plate thickness to perforation hole diameter ratio. In general, the loss coefficient decreases with increasing free-area ratio and increasing thickness-to-hole diameter ratio. A model based on the data is presented that predicts the loss coefficient for multiholed perforated plates with nonrounded holes. Furthermore, the data show that the cavitation number at the points of cavitation inception and critical cavitation increases with increasing free-area ratio. However, with regard to the thickness-to-hole diameter ratio, the cavitation number at inception exhibits a local maximum at a ratio between 0.5 and 1.0. Empirical models to allow prediction of the point of cavitation inception and the point where critical cavitation begins are presented and compared to single hole orifice plate behavior.

scholarly journals PENGARUH ADANYA MATERIAL BERPORI TERHADAP KARAKTERISTIK KONSOLIDASI TANAH LEMPUNG LUNAK LAHAN BASAH

2018 ◽  
Vol 1 (2) ◽  
pp. 127
Author(s):  
Rusdiansyah Rusdiansyah
Keyword(s):  
Porous Material ◽  
Rice Husk ◽  
Clay Soil ◽  
Soft Clay ◽  
Diameter Ratio ◽  
Vertical Drain ◽  
Optimum Diameter ◽  
Consolidation Coefficient ◽  
Degree Of Consolidation ◽  
Sand Rice

Salah satu cara untuk mempercepat aliran air maupun laju konsolidasi tanah lempung lunak lahan basah yaitu dengan menambahkan material porous didalam tanah maupun menggunakan drainasi vertical. Selama ini telah berkembang teknologi percepatan konsolidasi dengan vertical drain berbahan geosintetis. Selain berbahan geosintetis, bahan lainnya untuk material vertical drain masih terus dikembangkan untuk mencari keandalan yang ekonomis.Adapun yang menjadi permasalahan dalam penelitian ini adalah bagaimana derajat konsolidasi yang dihasilkan dari hasil pengujian konsolidasi tanah lempung lunak lahan basah yang ditambahkan adanya material berpori (berbahan pasir, sekam padi, dan arang kayu). Selain itu juga bagaimana pengaruh drainase (material berpori) radial, n (perbandingan diameter benda uji dan diameter drainase (material berpori)dari masing-masing material berpori.Dalam penelitian ini dilakukan uji konsolidasi dengan benda uji menggunakan tanah lempung lunak lahan basah. Pada bagian tengah benda uji diberi lubang berdiameter 0,75cm, 1cm, dan 1,5cm, kemudian  ditambahkan material berpori berbahan pengisi berupa pasir, sekam padi, dan arang. Dari ketiga material berpori tersebut, selanjutnya akan dibandingkan sesamanya terkait kinerja material berpori sebagai sistem drainase (material berpori) didalam tanah. Hasil penelitian menunjukkan bahwa material sekam padi, pasir, dan arang dapat digunakan sebagai bahan drainase (material berpori) untuk tanah yang berkonsolidasi karena mampu meningkatkan nilai derajat konsolidasi (U%).Apabila ditinjau pada satu satuan waktu maka untuk jenis material drainase (material berpori)) berbahan sekam dapat menghasilkan derajat konsolidasi yang lebih besar dibandingkan material drainase (material berpori) berbahan pasir maupun arang.Material drainase (material berpori) berbahan sekam dapat menghasilkan nilai koefisien konsolidasi (Cv), nilai koefisien permeabilitas (k), dan nilai koefisien perubahan volume (mv) yang lebih besar dibandingkan dengan material drainase (material berpori) berbahan pasir dan arang.Nilai koefisien konsolidasi (Cv) semakin meningkat seiring dengan peningkatan nilai rasio diameter (n) hingga mencapai rasio diameter yang optimum (nopt), selanjutnya sesudah nilai rasio diameter optimum tercapai maka koefisien konsolidasi akan  mengalami penurunan. Rasio diameter optimum pada tanah lempung lunak yang berkonsolidasi didapat pada nilai 6(enam).Kata kunci : Konsolidasi tanah, drainase (material berpori) vertical,derajat konsolidasi,koefisien permeabilitas, koefisien konsolidasi dan tanah lempung lunak lahan basah.One way to accelerate water flow and the rate of consolidation of wetland soft clay soil is by adding porous material in the soil and using vertical drainage. So far there has been a development of consolidation acceleration technology with a vertical drain made from geosynthetics. Apart from geosynthetics, other materials for vertical drain material are still being developed to find economical reliability. The problem in this research is how the degree of consolidation resulting from the consolidation test of wetland soft clay soil is added by the presence of porous material (made from sand, rice husk, and wood charcoal). In addition, also the effect of radial drainage (porous material), n (comparison of the diameter of the specimen and drainage diameter (porous material) of each porous material. In this study a consolidation test was carried out with specimens using soft soil wetlands. the center of the specimen was given a hole with a diameter of 0.75cm, 1cm, and 1.5cm, then added porous material made from fillers in the form of sand, rice husk, and charcoal. porous material) in the soil The results showed that rice husk, sand and charcoal material can be used as drainage material (porous material) for the soil that consolidates because it can increase the value of the consolidation degree (U%). for the type of drainage material (porous material) made from chaff can produce console degrees idasi which is bigger than drainage material (porous material) made from sand or charcoal. Drainage material (porous material) made from chaff can produce consolidated coefficient values (Cv), permeability coefficient value (k), and volume change coefficient value (mv) which is greater than the drainage material (porous material) made from sand and charcoal. The value of the consolidation coefficient (Cv) increases along with the increase in the diameter ratio (n) until it reaches the optimum diameter ratio (nopt), then after the optimum diameter ratio value is reached, the coefficient of consolidation will decrease. The optimum diameter ratio in soft clay that consolidates is obtained at a value of 6 (six). Keywords: Soil consolidation, vertical drainage (porous material), degree of consolidation, permeability coefficient, consolidation coefficient, and wetland soft clay soil. 

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