Experimental Study and Numerical Simulation on Hydrodynamic Performance of a Twisted Rudder

AbstractTo analyze the energy-saving effect of a twisted rudder, this work presents the simulated and experimental results of propeller-rudder systems. In this article, a surface panel method (SPM) and computational fluid dynamics (CFD) are introduced to simulate the hydrodynamic performance of propeller-rudder systems. The thrust coefficient Kt, torque coefficient Kq, open-water efficiency η of the propeller, and thrust coefficient Kr of the rudder as a function of the advance coefficient J are obtained and plotted. The energy-saving effect of the twisted rudder is analyzed by comparing the results of numerical simulation and a cavitation tunnel experiment. The experimental energy-saving effect is 2.23% at the design advance coefficient J = 0.8. The pressure distributions of the propeller blade and rudder are plotted by two methods, and the difference of the force on an ordinary rudder and a twisted rudder is discussed. This study improved the experimental twisted rudder model. The change makes the rudder take advantage of propeller wake and improves the energy-saving effect of a twisted rudder. After improvement, the energy-saving effects obtained by the two methods are 0.448% and 0.441%. To analyze the energy-saving mechanism, this study compares the pressure distributions and efficiencies of different systems.

Download Full-text

The Research of Hydrodynamic Performance for Ducted Propeller with PBCF

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.733.578 ◽

2015 ◽

Vol 733 ◽

pp. 578-582

Author(s):

Zhen Qiu Yao ◽

Xin Gu ◽

Yun Shen

Keyword(s):

Energy Saving ◽

Open Water ◽

Hydrodynamic Performance ◽

Thrust Coefficient ◽

Rotation Direction ◽

Ducted Propeller ◽

Efficiency Increase ◽

Good Energy ◽

Torque Coefficient ◽

Saving Effect

The Propeller Boss Cap Fins (PBCF) is often used to ordinary propeller, a good energy-saving effect being obtained. In order to study the energy-saving mechanism of ducted propeller with PBCF, in this paper, the FLUENT has been taken to simulate the distribution of thrust coefficient, torque coefficient, blade pressure and velocity vector of hub surface at different advance coefficients. By contrasting the results of numerical simulation of hydrodynamic performance of ducted propeller between with fins and without fins, we know that at the low advance coefficient, the ducted propeller with fins will increase the thrust coefficient and decrease the torque coefficient; rising the open water propeller efficiency, improving the efficiency under the premise of the efficiency increase by duct. The existence of fins has changed velocity distribution of water around the hub and made the water that flowed around the propeller hub with propeller rotation direction flow to propeller tail along the fins not gather in the cub, so it weakened the hub vortex.

Download Full-text

Numerical Analysis of Hydrodynamic Performance of FX-83-W Hydrofoil Current Turbine

Volume 1: Advances in Aerospace Technology ◽

10.1115/imece2017-70995 ◽

2017 ◽

Author(s):

Yuchen Shang ◽

Nikolaos I. Xiros

Keyword(s):

Numerical Simulation ◽

Three Dimensional ◽

Flow Characteristics ◽

Open Water ◽

Hydrodynamic Performance ◽

Ocean Current ◽

Thrust Coefficient ◽

Cfd Method ◽

Three Dimensional Coordinate ◽

Current Turbine

Ocean current flow characteristics are relatively stable and predictable, current turbine absorbs the energy of the ocean currents by the blades with a relative stable and lower angular velocity which indicates the capacity of current turbine greater than the onshore wind turbine. In this paper, the CFD method is utilized to calculate and analyze the working principle of FX-83-W current turbine. The three-dimensional coordinate of FX-83-W Hydrofoil blade surface have been calculated by MATLAB code, and 3D model has been established in Gambit. The basic control equations of CFD and its numerical solution are described, Reynolds Averaged N-S equations is used, and the realizable k-e turbulence model is introduced to solve the Reynolds stress in the RANS equation. The numerical algorithm is the finite volume method (FVM), and the numerical simulation of CFD is used to study the open water performance, leading to thrust coefficient KT and torque coefficient KQ of FX-83-W Hydrofoil. The hydrodynamic thrust and hydrodynamic power of the ocean current turbine under different sea conditions have been obtained by numerical simulation.

Download Full-text

Numerical Investigation of Different Tip Clearances Effect on the Hydrodynamic Performance of Pumpjet Propulsor

International Journal of Computational Methods ◽

10.1142/s0219876218500378 ◽

2018 ◽

Vol 15 (05) ◽

pp. 1850037 ◽

Cited By ~ 9

Author(s):

Denghui Qin ◽

Guang Pan ◽

Qiaogao Huang ◽

Zhengdong Zhang ◽

Jiujiu Ke

Keyword(s):

Numerical Simulation ◽

Rotor Blade ◽

Fluid Dynamic ◽

Open Water ◽

Suction Side ◽

Close Relation ◽

Tip Clearance ◽

Tip Vortex ◽

Hydrodynamic Performance ◽

Cfd Method

Previous studies show that the tip clearance loss limits the improvement of turbomachinery performance, and it is roughly in close relation with the gap size. In this study, a pumpjet propulsor (PJP) with different sizes of tip clearances ([Formula: see text], 0.5, 1, 2, 3[Formula: see text]mm) has been presented to investigate the influence of tip clearances on PJP. This analysis is based on computational fluid dynamic (CFD) method, and the SST k-[Formula: see text] turbulence model is applied. Calculations are carried out with a worldwide employed ducted propeller (the Ka4-70 propeller in 19A duct) to verify the numerical simulation. And the grid independence validation is discussed. The numerical simulation of PJP flow with different tip clearances is carried out. Results show that the open water efficiency decreases gradually with the increase of tip clearance. The efficiency decreasing is caused by the tip flow loss. The shape of tip vortex of PJP which consisted of tip-separation vortex and tip-leakage vortex is presented. Furthermore, the formation and spread process of tip vortex at different tip clearances are discussed. Then, the effect of different tip clearances on the pressure field of rotor blade is investigated. The main pressure area affected by different tip clearances is mainly concentrated in the area above 0.9 spanwise of the suction side of rotor blade. Beyond that, the effects of different tip clearances on the velocity field of PJP has been studied.

Download Full-text

Simulation Analysis of Building Energy Consumption with Different Surface-Volume-Ratio and Envelop Performance of Rural Dwellings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.953-954.1578 ◽

2014 ◽

Vol 953-954 ◽

pp. 1578-1583

Author(s):

Tian Yu Xiong ◽

Xiu Zhang Fu ◽

Jian Dong

Keyword(s):

Energy Consumption ◽

Energy Saving ◽

Simulation Analysis ◽

Volume Ratio ◽

National Standard ◽

Heating And Cooling ◽

Detached House ◽

The Difference ◽

Saving Effect ◽

The Impact

Rural dwellings have a big difference in the appearance and envelope. Living form is changing a lot from detached house to the apartment in multi-story apartments. These changes affect building’s energy consumption consisting of heating and cooling. This paper focuses on the impact of the energy consumption affected by different surface volume ratios, simulation analysis showed a general argument of the difference. And for the same house type, this paper also compares the energy-saving effect of different envelop performances, Specific contents are the heat transfer coefficient and shading ways. Simulation results identified that SVR has influence on different types of houses, the energy consumption of row houses can be saved more than 30% compared with detached houses. Envelope performance also affects energy consumption and the national standard is recommended for the energy saving and the comfort.

Download Full-text

The Application of On-Off Regulation in Public Buildings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.918.325 ◽

2014 ◽

Vol 918 ◽

pp. 325-330

Author(s):

Lan Bin Liu ◽

Ai Juan Zou ◽

Li Xia Ma ◽

Ya Meng Liu

Keyword(s):

Energy Saving ◽

Northern China ◽

High Energy ◽

Vertical Tube ◽

Control Effect ◽

Indoor Temperature ◽

Circulating Water ◽

The Difference ◽

Lower Temperature ◽

Saving Effect

Focusing on the phenomenon that many office buildings and student apartments in northern China with vertical single tube series heating systems are of high energy consumption and waste lots of thermal energy because of lacking heating regulation, this paper proposed a system of on-off regulation to optimize the regulation, where on-off values are installed in each vertical riser, indoor temperature controllers are installed in the room with lower temperature, and the on-off values control circulating water automatically according to the difference between the real temperature and the set temperature and finally the indoor temperatures are controlled. The temperature control effect and energy saving effect of this system were discussed in both simulation and measurement. The conclusion shows that: 1) the proposed system can optimize heating regulation and reduce the loss cause of heating non-uniformity.2) the on-off control on the flow of single vertical tube makes temperature of all rooms stringed in the riser meet the requirements.3) the indoor temperature differences in the same riser are controlled in 2 °C.4) in practical, users on-time is only 50% of total time through on-off regulation, the effect of energy saving is significant.

Download Full-text

Numerical Study of Hub Taper Angle on Podded Propeller Performance

Marine Technology and SNAME News ◽

10.5957/mt1.2006.43.1.1 ◽

2006 ◽

Vol 43 (01) ◽

pp. 1-10

Author(s):

Mohammed F. Islam ◽

Brian Veitch ◽

Neil Bose ◽

Pengfei Liu

Keyword(s):

Numerical Study ◽

Open Water ◽

Propulsion Systems ◽

Taper Angle ◽

Propulsive Performance ◽

Pressure Distributions ◽

Overall Performance ◽

The Difference ◽

Propeller Blades ◽

Propeller Performance

Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller-type podded propulsor. One is related to the difference in hub taper angle. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same design of blade sections, but different hub taper angles. A hyperboloidal low-order source-doublet steady/unsteady time domain panel method code, PROPELLA, was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed-pitch screw propellers used in podded propulsion systems. Major findings include good agreement between predictions using the modified code and measurements, significant effects of hub taper angle on propulsive performance of tapered hub propellers, and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades.

Download Full-text

Numerical Simulation of the Ducted Propeller and Application to a Semi-Submerged Vehicle

Polish Maritime Research ◽

10.2478/pomr-2020-0023 ◽

2020 ◽

Vol 27 (2) ◽

pp. 19-29

Author(s):

Jin Zou ◽

Guoge Tan ◽

Hanbing Sun ◽

Jie Xu ◽

Yongkang Hou

Keyword(s):

Numerical Simulation ◽

Numerical Simulations ◽

Open Water ◽

The Self ◽

Hydrodynamic Performance ◽

Navier Stokes ◽

Cfd Simulations ◽

Ducted Propeller ◽

Numerical Software ◽

Numerical Approaches

AbstractThe self-propulsion test of underwater vehicles is the key technique for predicting and evaluating the navigation performance of these submersibles. In this study, the numerical simulation of a standard propeller JD7704+Ka4-70 is first presented and the results are compared with experiments to validate the numerical approaches. The reason why the propulsion efficiency of the ducted propeller is higher than that of the conventional propeller is explored. Then, the paper proposes a series of numerical simulations conducted to test the performance of the ducted propeller designed according to the JD7704+Ka4-70 in order to match with the unmanned semi-submerged vehicle (USSV), and the propeller’s open water characteristic curves are obtained. The results show a reasonable agreement with the regression analysis. Afterwards, the numerical simulations focus on a self-propulsion test of the USSV with the designed ducted propeller and the self-propulsion point is obtained. The streamlines through the hull as well as the ducted propellers are clearly obtained, together with the velocity distributions of the propeller plane. The results vividly demonstrate the hydrodynamic performance of the USSV with the designed propellers. In this paper, all the CFD simulations are based on the numerical software, Star-CCM+, and use the Reynolds-averaged Navier‒Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model.

Download Full-text

The Numerical Simulation and Research and Application of Energy-Saving Effect of Hot Air Curtain Jet Velocity of the Dining Room

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.919-921.1744 ◽

2014 ◽

Vol 919-921 ◽

pp. 1744-1747

Author(s):

Kun Ru Ma ◽

Xin Wang

Keyword(s):

Numerical Simulation ◽

Energy Saving ◽

Physical Model ◽

Outdoor Air ◽

Air Curtain ◽

Hot Air ◽

Jet Velocity ◽

Dining Room ◽

Set Up ◽

Saving Effect

There are often people and goods in and out of the dinning room door, so the door is often open. Heating and air conditioning construction to save energy and to prevent the outdoor air form influencing on indoor environment, set up the air curtain at the entrance of the dinning room to stop outdoor air, the frequently-used air curtain is beam type of air curtain.The project in view of the dinning room of the new campus of hebei university of science and technology, sets up air curtain physical model of the ground floor dining room door at the first area, and carry on reasonable simplification, make sure the numerical simulation calculation area and the sealing condition of air curtain. Then set up physical model for wind pressure, multiply of hot pressure and the local hot pressure at the dinning room door of the air curtain air flow in CFD method. Through the numerical simulation for different jet velocity of the hot air curtain, analysis the temperature field, velocity field, heat loss,heat load parameter, etc. and demonstrate the energy saving effect, and provide reference basis for the selection of air curtain.

Download Full-text

The Numerical Simulation and Research and Application of Energy-Saving Effect of Air Curtain of the Dining Room

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.548-549.1739 ◽

2014 ◽

Vol 548-549 ◽

pp. 1739-1743

Author(s):

Kun Ru Ma ◽

Yi Jun Wang ◽

Xin Wang

Keyword(s):

Numerical Simulation ◽

Energy Saving ◽

Physical Model ◽

Wind Pressure ◽

Outdoor Air ◽

Air Curtain ◽

Dining Room ◽

Set Up ◽

Saving Effect ◽

Close Condition

The dining room door with going out and coming in of people and goods is often opened, heating and air-conditioning building in order to energy-saving and preventing the outdoor air on indoor environment influence, install a set of air curtain at the entrance of the dining room door to stopping the outdoor air, commonly used air curtain is ceiling type air curtain. This article in view of the gate of one area, a layer of the dining room of Hebei University of science and technology of a new campus area set up physical model of air curtain and reasonable simplification, determining the calculation area of the numerical simulation and air curtain close condition. Then adopting the UFD method to wind pressure, hot pressure and the air curtain air flowing of the local hot pressure stack of main entrance set up physical model, through the numerical simulation of air curtain different jet angle, demonstrate the air energy-saving effect, provide the reference for the choice of the air curtain.

Download Full-text