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.

Integrated Optimal Design of Ducted Propeller Based on DOE

2011 ◽  
Vol 291-294 ◽  
pp. 1698-1703 ◽  
Author(s):  
Zhuo Yi Yang ◽  
Yan Ma ◽  
Yan Xue Chen
Keyword(s):  
Design Method ◽  
Integrated Design ◽  
Panel Method ◽  
Hydrodynamic Performance ◽  
Surface Panel Method ◽  
Optimal Method ◽  
Scheme Design ◽  
Propeller Design ◽  
Design Variables ◽  
Ducted Propeller

Ducted propeller is a normal thrust used widely in ship field, and the traditional design method could be improved by advanced computer technology of integrated design. Surface panel method predicting hydrodynamic performance of propeller and CFD were both used here, to ensure the results from surface panel method were believable. Surface panel program of ducted propeller was integrated in iSIGHT optimization platform, where the pitches in different radius were optimized and studied to find the best scheme. Design of experiment was selected as optimal method. Design variables were auto-chosen in the design space and optimal process was auto-executed. Besides, the effect of parameters to objective was gained. The final result showed that this method which can improve the efficiency of ducted propeller and realize the motivation provided a new idea for propeller design.

scholarly journals Utilization of Open-Source OpenFOAM Code to Examine the Hydrodynamic Characteristics of a Linear Jet Propulsion System with or without Stator in Bollard Pull Condition

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Parviz Ghadimi ◽  
Negin Donyavizadeh ◽  
Pouria Taghikhani
Keyword(s):  
High Speed ◽  
Water Jet ◽  
Propulsion System ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Propulsion Systems ◽  
Thrust Coefficient ◽  
Jet Propulsion ◽  
Marine Industry ◽  
Total Thrust

With the development of high-speed crafts, new propulsion systems are introduced into the marine industry. One of the new propulsion systems is linear jet which is similar to pump jet and has a rotor, a stator, and a duct. The main difference between this system and pump jet is the placement of linear jet system under the hull body and inside a tunnel. Since this system, like a water jet, is inside the tunnel, the design idea of this system is a combination of a water jet and pump jet. In this paper, hydrodynamic performance of linear jet propulsion system is numerically investigated. To this end, the OpenFOAM software is utilized and RANS steady equations are solved using a k - ε turbulent model. The linear jet geometry is produced by assembling a Kaplan rotor, stator with a NACA 5505 cross section, and a decelerating duct. The results of numerical solution in the form of thrust, torque coefficient, and efficiency are compared with available experimental data for a ducted propeller, and good agreement is displayed. Subsequently, the hydrodynamic parameters are computed in two conditions: with a stator and without a stator. By comparing the results, it is observed that the total thrust coefficient of the propulsion system with a stator at all advance ratios increases by at least 40%. It is further observed that addition of a stator also improves its efficiency.

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.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

scholarly journals Monte Carlo Modeling and Design of Photon Energy Attenuation Layers for >10× Quantum Yield Enhancement in Si-Based Hard X-ray Detectors

Instruments ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 17
Author(s):  
Eldred Lee ◽  
Kaitlin M. Anagnost ◽  
Zhehui Wang ◽  
Michael R. James ◽  
Eric R. Fossum ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Quantum Yield ◽  
Photon Energy ◽  
High Efficiency ◽  
High Energy ◽  
Yield Enhancement ◽  
X Ray ◽  
Simulation Results ◽  
Conversion Efficiencies

High-energy (>20 keV) X-ray photon detection at high quantum yield, high spatial resolution, and short response time has long been an important area of study in physics. Scintillation is a prevalent method but limited in various ways. Directly detecting high-energy X-ray photons has been a challenge to this day, mainly due to low photon-to-photoelectron conversion efficiencies. Commercially available state-of-the-art Si direct detection products such as the Si charge-coupled device (CCD) are inefficient for >10 keV photons. Here, we present Monte Carlo simulation results and analyses to introduce a highly effective yet simple high-energy X-ray detection concept with significantly enhanced photon-to-electron conversion efficiencies composed of two layers: a top high-Z photon energy attenuation layer (PAL) and a bottom Si detector. We use the principle of photon energy down conversion, where high-energy X-ray photon energies are attenuated down to ≤10 keV via inelastic scattering suitable for efficient photoelectric absorption by Si. Our Monte Carlo simulation results demonstrate that a 10–30× increase in quantum yield can be achieved using PbTe PAL on Si, potentially advancing high-resolution, high-efficiency X-ray detection using PAL-enhanced Si CMOS image sensors.

Intelligent Information of TS Fuzzy PID Control System of BLDCM

2013 ◽  
Vol 846-847 ◽  
pp. 313-316 ◽  
Author(s):  
Xiao Yun Zhang
Keyword(s):  
Control System ◽  
Dynamic Model ◽  
Pid Control ◽  
Control Method ◽  
Design Method ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Control Precision ◽  
Simulation Results ◽  
Intelligent Information

This paper presented a new method based on the Fuzzy self - adaptive PID for BLDCM. This method overcomes some defects of the traditional PID control. Such as lower control precision and worse anti - jamming performance. It dynamic model of BLDCM was built, and then design method for TS fuzzy PID model is given, At last, it compared simulation results of PID control method with TS Fuzzy PID control method. The results show that the TS Fuzzy PID control method has more excellent dynamic antistatic performances, as well as anti-jamming performance. The experiment shows that TS fuzzy PID control has the stronger adaptability robustness and transplant.

The Design of 5V/100W High Frequency Switching Power Supply

2013 ◽  
Vol 834-836 ◽  
pp. 1221-1224
Author(s):  
Hong Zhuan Cai ◽  
Li Bai
Keyword(s):  
Power Supply ◽  
High Frequency ◽  
High Efficiency ◽  
Design Method ◽  
Switching Power Supply ◽  
Widespread Application ◽  
Forward Converter ◽  
Switching Power ◽  
Dc Power ◽  
Important Field

Switching power supply is an important field of application of power electronic technology, the high frequency switching DC power supply with high efficiency, small size, light weight and other advantages obtain the widespread application. The application of synchronous rectifier technology, photoelectric coupling isolation technology and the active clamp forward converter design high frequency switching power supply with 16~40V DC input and 5V/100W DC output . its operational principle is analyzed, and using LM5026 control chip describes design method of switching power supply.

A Design Method of LS-SVM Based Stable Adaptive Controller for a Class of Nonlinear Systems

2011 ◽  
Vol 48-49 ◽  
pp. 17-20
Author(s):  
Chun Li Xie ◽  
Tao Zhang ◽  
Dan Dan Zhao ◽  
Cheng Shao
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Nonlinear Function ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Control Law ◽  
Continuous Systems ◽  
Control Schemes ◽  
Closed Systems ◽  
Simulation Results

A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

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