The Research of Hydrodynamic Performance for Ducted Propeller with PBCF

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.

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

2015 ◽  
Vol 49 (5) ◽  
pp. 58-69 ◽  
Author(s):  
Yu Sun ◽  
Yu-min Su ◽  
Hai-zhou Hu
Keyword(s):  
Numerical Simulation ◽  
Energy Saving ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Surface Panel Method ◽  
Thrust Coefficient ◽  
Propeller Wake ◽  
Pressure Distributions ◽  
The Difference ◽  
Saving Effect

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.

A New Type of Energy-Saving Magnetic Amplifier Controlling Inductive Load

2011 ◽  
Vol 347-353 ◽  
pp. 3995-3998
Author(s):  
Shuai Yang ◽  
Lan Xue ◽  
Jian Sheng Cheng
Keyword(s):  
Energy Saving ◽  
Iron Core ◽  
Inductive Load ◽  
Sodium Lamp ◽  
Core Column ◽  
Good Energy ◽  
New Type ◽  
Magnetic Amplifier ◽  
Saving Effect ◽  
High Pressure Sodium Lamp

A new type of energy-saving magnetic amplifier controlling current and voltage of inductive load has been designed. The energy-saving magnetic amplifier with two windings wrapped across one iron core column can change impedance of the main winding by means of PWM controlling AC excitation current. The energy-saving magnetic amplifier has not used a special adjustable DC voltage circuit, has overcome disadvantages of complicated manufacturing process for the traditional excitation amplifier.The application shows the energy-saving excitation amplifier can achieve stepless dimming for high pressure sodium lamp to good energy-saving effect. The use cost of excitation amplifier is lower as simple production process, so its promotional value is great.

An Investigation Into the Effect of Biofouling on Full-Scale Propeller Performance Using CFD

2019 ◽  
Author(s):  
Soonseok Song ◽  
Yigit Kemal Demirel ◽  
Mehmet Atlar
Keyword(s):  
Open Water ◽  
Full Scale ◽  
Roughness Effect ◽  
Thrust Coefficient ◽  
Propulsion Performance ◽  
Negative Effect ◽  
Precise Prediction ◽  
Torque Coefficient ◽  
Open Water Performance ◽  
Propeller Performance

Abstract The negative effect of biofouling on ship resistance has been investigated since the early days of naval architecture. However, for more precise prediction of fuel consumption of ships, understanding the effect of biofouling on ship propulsion performance is also important. In this study, CFD simulations for the full-scale performance of KP505 propeller in open water, including the presence of marine biofouling, were conducted. To predict the effect of barnacle fouling on the propeller performance, experimentally obtained roughness functions of barnacle fouling were employed in the wall-function of the CFD software. The roughness effect of barnacles of varying sizes and coverages on the propeller open water performance was predicted for advance coefficients ranging from 0.2 to 0.8. From the simulations, drastic effects of barnacle fouling on the propeller open water performance were found. The result suggests that the thrust coefficient decreases while the torque coefficient increases with increasing level of surface fouling, which leads to a reduction of the open water efficiency of the propeller. Further investigations into the roughness effect on the pressure and velocity field, surface pressure and wall shear stress, and propeller vortices were examined.

Simulation and Energy-Saving Algorithm Based on MRAC of VAV BOX

2013 ◽  
Vol 732-733 ◽  
pp. 615-619
Author(s):  
Jia Shi Chen ◽  
Zheng Song Wu ◽  
Yang Liu ◽  
Shan Chi Lin
Keyword(s):  
Energy Saving ◽  
Lyapunov Stability Theory ◽  
Air Conditioning System ◽  
Variable Air Volume ◽  
Air Volume ◽  
Good Energy ◽  
Saving Effect ◽  
Model Reference Adaptive ◽  
Saving Algorithm ◽  
Modern Building

A model reference adaptive control (MRAC) algorithm is proposed to the air-conditioning system of variable air volume (VAV) terminal units (VAV BOX). The study of temperature controlling parameters in room area (Zone) is based on Lyapunov stability theory. We built the simulation model in Matlab to validate the superior controlling performance and good energy saving effect of the algorithm. The research shows that the energy consumption release 60% ~70% in larger room. In modern building, the energy saving and comfort is very important, so the simulation has important engineering practical value.

Unsteady Hydrodynamic Performance Prediction of Ducted Propeller Based on CFD

2013 ◽  
Vol 437 ◽  
pp. 32-35
Author(s):  
Li Jian Ou ◽  
Nan Huo Wu ◽  
De Yu Li
Keyword(s):  
Performance Prediction ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Moving Mesh Method ◽  
Ducted Propeller ◽  
Mesh Method ◽  
Bearing Force ◽  
Thrust And Torque ◽  
Wake Fields ◽  
Calculated Model

Firstly, the calculated model was created in UG and GAMBIT, and then the Moving Mesh method was adopted to simulate thrust and torque of ducted propeller using FLUENT in the open water. The thrust, torque and bearing force of ducted propeller in three different wake fields were calculated. And the influence on the performance of ducted propeller by the wake fields was analyzed.

scholarly journals Thermodynamic Features and Design of Solar-Air Source Composite Heating System

2020 ◽  
Vol 38 (4) ◽  
pp. 967-975
Author(s):  
Na Ni
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Heat Supply ◽  
Water Source ◽  
Heating System ◽  
Heating And Cooling ◽  
Cooling Devices ◽  
Good Energy ◽  
Saving Effect ◽  
Independent Heat

Facing the huge energy consumption of buildings, it is highly practical to study every aspect of energy-saving technologies for heating and cooling devices. Solar thermal technology and air/water source heat pump are two popular energy-saving technologies, which could be combined into a composite heating system with good energy-saving effect and efficiency. This paper constructs a solar-air source composite heating system, analyzes its thermodynamic features, and builds up the corresponding thermodynamic model. In addition, the authors modeled the daytime and nighttime heat balances, as well as the monthly cumulative heat supply for the constructed system. Finally, a dual-tank composite heating system was designed with independent heat supply/storage. The proposed models and system were proved valid and scientific through experiments.

scholarly journals Calculations of the Hydrodynamic Characteristics of a Ducted Propeller Operating in Oblique Flow

2017 ◽  
Vol 10 (20) ◽  
pp. 31
Author(s):  
Hassan Ghassemi ◽  
Sohrab Majdfar ◽  
Hamid Forouzan
Keyword(s):  
Stokes Equations ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Numerical Code ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Navier Stokes Equations ◽  
Oblique Flow ◽  
Ducted Propeller ◽  
Acceptable Agreement

The purpose of this paper is to calculate the hydrodynamic performance of a ducted propeller (hereafter Duct_P) at oblique flows. e numerical code based on the solution of the Reynolds-averaged Navier– Stokes equations (RANSE) applies to the Kaplan propeller with 19A duct. e shear-stress transport (SST)-k-ω turbulence model is used for the present results. Open-water hydrodynamic results are compared with experimental data showing a relatively acceptable agreement. Two oblique flow angles selected to analyze in this paper are 10 and 20 degrees. Numerical results of the pressure distribution and hydrodynamic performance are presented and discussed. 

Studies About Design of Rear Stator of Ducted Propeller Using CFD

2019 ◽  
Author(s):  
Dakui Feng ◽  
Hang Zhang ◽  
Yue Sun ◽  
Qing Wang ◽  
Xiaofei Hu
Keyword(s):  
High Efficiency ◽  
Design Method ◽  
Hydrodynamic Performance ◽  
Thrust Coefficient ◽  
Wake Field ◽  
Ducted Propeller ◽  
Total Thrust ◽  
Unsteady Rans ◽  
Simulation Results ◽  
Volume Method

Abstract Ducted propeller designs are becoming more popular because of their high efficiency, resistance to cavitation and low radiated noise. In this paper, unsteady RANS simulations are carried out for the design of rear stators for ducted propeller to improve its hydrodynamic performance. The design of rear stator is carried out based on the wake field behind propellers. The two-dimensional airfoil modified from NACA4603 is studied to obtain the angle of attack that makes thrust on stators maximum. The analyses are performed at different angles of attack, using commercial computational fluid dynamics (CFD) solver STAR-CCM+ to solve URANS equations. URANS equations are discretized by finite volume method and solved by PISO algorithm. Simulations have been made using unstructured grid with mesh moving technique. The simulation results indicate that the total thrust coefficient and efficiency of modified ducted propeller have been improved by 7.32% and 5.72% respectively compared with the parent one. The simulation results show that the design method is reasonable and feasible.

Numerical Analysis of Propeller During Heave Motion Near a Free Surface

2017 ◽  
Vol 51 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Wang Lian-zhou ◽  
Guo Chun-yu ◽  
Wan Lei ◽  
Su Yu-min
Keyword(s):  
Free Surface ◽  
Coupling Effect ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Grid Technology ◽  
Thrust Coefficient ◽  
Motion State ◽  
Sinusoidal Motion ◽  
Torque Coefficient ◽  
Heave Motion

AbstractThe interaction between the free surface and the propeller during heave motion near the free surface was analyzed numerically using the Reynolds-Averaged Navier-Stokes (RANS) method. The coupling effect between the rotation and heave motions of the propeller was modeled using a motion equation developed in this study; the heave motion was simplified as a periodic motion based on the sinusoidal motion law; and the transfer of numerical values for unsteady flow fields was implemented using overset grid technology. A comparative analysis of the unsteady thrust coefficient and torque coefficient under different advance coefficient conditions was conducted, and the air ingestion phenomenon of the propeller was analyzed. The research highlighted the interaction between the coupled heave and rotation motions of the propeller and the free surface. The results showed that, when the advance coefficient was low, the hydrodynamic performance of the propeller during heave motion near a free surface was strongly influenced by the free surface and that a remarkable interaction existed between the propeller and the free surface. As the advance coefficient increased, the interaction between the propeller and the free surface weakened. The air ingestion that the propeller exerts upon the free surface during heave motion is a complex coupled superposition process. This phenomenon is correlated to the motion state and working time of the propeller, as well as the distance between the propeller and the free surface.

Experimental Study and Hydrodynamic Performance Analysis of a Bio-Tail Fin Propellant System

2009 ◽  
Vol 419-420 ◽  
pp. 77-80 ◽  
Author(s):  
Yu Min Su ◽  
Shi Qi Zhao ◽  
Liang Yang
Keyword(s):  
Experimental Data ◽  
Lateral Force ◽  
Hydrodynamic Performance ◽  
Force Coefficient ◽  
Thrust Coefficient ◽  
Propulsion Efficiency ◽  
Design Concepts ◽  
Torque Coefficient ◽  
Precise Experimental Data ◽  
Selection Of

In order to research the bionic mechanics in unsteady flow and the hydrodynamic performance of the oscillating tail fin, in this paper, an experimental device imitating bionic tail fin were built, the design concepts and the rolling systems of the mechanical tail fins were demonstrated, including the procedures and correlated works on the selection of the servo motors, online control and signal data collecting and processing. The movements of the mechanical tail fin could be optimized by the comparisons of the propulsion efficiency, thrust coefficient, lateral force coefficient and torque coefficient at different conditions. Meanwhile, error analysis is carried out to correct the movement curves and obtain more precise experimental data and results.

Sign in / Sign up

Export Citation Format

Share Document