A propulsion unit for ships based on water-treading of flapping foils

2021 ◽  
Vol 235 ◽  
pp. 109330
Author(s):  
Yiping Zhang ◽  
Li Xu
Keyword(s):  
Propulsion Unit ◽  
Flapping Foils

scholarly journals Analytical Modeling and Design of Novel Conical Halbach Permanent Magnet Couplings for Underwater Propulsion

2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao
Keyword(s):  
Permanent Magnet ◽  
Analytical Calculation ◽  
Underwater Propulsion ◽  
Conical Structure ◽  
Torque Analysis ◽  
Dynamic Seal ◽  
And Performance ◽  
The Stability ◽  
Propulsion Unit ◽  
Force Calculation

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

Propulsion Unit Control Method for Visualization of Grasping State of Earthworm-type Lunar Excavation Robot

2021 ◽  
Author(s):  
R. Tokoi ◽  
W. Toyama ◽  
T. Watanabe ◽  
K. Tsumura ◽  
M. Okui ◽  
...  
Keyword(s):  
Control Method ◽  
Propulsion Unit

scholarly journals Material Origins of Accelerated Operational Wear of RD-33 Engine Blades

2020 ◽  
Author(s):  
Adam Kozakiewicz ◽  
Stanislaw Jóźwiak ◽  
Przemysław Jóźwiak ◽  
Stanisław Kachel
Keyword(s):  
Chemical Composition ◽  
Construction Material ◽  
Operating Conditions ◽  
Design Stage ◽  
Strength Analysis ◽  
Jet Engine ◽  
Emergency Situations ◽  
Low Pressure Turbine ◽  
Propulsion Unit ◽  
Selection Of

The structural and strength analysis of the material used to construct such an important engine element as the turbine is of great significance, both at the design stage as well as during tests and expertises related to emergency situations. Bearing in mind the conditions above mentioned, the paper presents the results of research on the chemical composition, morphology and phased structure of the metallic construction material used to produce the blades of the high and low pressure turbine of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. The data obtained as a result of the material tests of the blades allowed, on the basis of the analysis of chemical composition and phased structure, to determine the grade of the alloy used to construct the tested elements of the jet engine turbine. The structural stability of the material was found to be lower in comparison with engine operating conditions, which manifested itself as a clear decrease in the resistance properties of the blade material. The results obtained can be used as a basis for analyzing the life span of an object or a selection of material replacements, which enable to produce the analyzed engine element.

scholarly journals Comparative analysis of combustion engine and hybrid propulsion unit in aviation application in terms of emission of harmful compounds in the exhausts emitted to the atmosphere

2019 ◽  
Vol 178 (3) ◽  
pp. 213-217
Author(s):  
Marek ORKISZ ◽  
Piotr WYGONIK ◽  
Michał KUŹNIAR ◽  
Maciej KALWARA
Keyword(s):  
Comparative Analysis ◽  
Combustion Engine ◽  
Total Power ◽  
Exhaust Emission ◽  
Flight Trajectory ◽  
Hybrid Propulsion ◽  
Electric Generator ◽  
In Series ◽  
Propulsion Control ◽  
Propulsion Unit

Comparative analysis of combustion and hybrid propulsion unit in aviation application in terms of emission of harmful compounds in the exhausts emitted to the atmosphere. For the propulsion of the AOS 71 motor glider, two types of propulsion were planned as de-velopment versions. The first analysed propulsion is based on a combustion engine, but of the Wankel type (LCR 814 engine with the power of 55 kW). The second designed propulsion is an hybrid based on a LCR 407 combustion engine with a power of 28 kW, which is connected in series with an electric generator propelling the engine (Emrax 228 engine), total power of the propulsion is 55 kW. The comparison of emissions of harmful compounds emitted to the atmosphere generated by the combustion and hybrid power unit intended for assembly in the AOS 71 motor glider, assuming various loads and methods of hybrid propulsion control, was made. The tests were conducted in laboratory conditions. Several different programs were designed to simulate different energy management methods in a hybrid system, depending on the predicted mission and load of the motor glider. On the basis of laboratory tests, exhaust emission was determined from both propulsions as a function of rotational speed and load. Then, based on the assumed flight trajectory and collected test data, the emission for both propulsions variants was determined. The values of emission parameters were compared and the results were presented in diagrams and discussed in the conclusions

Reduced-Gravity Simulators for Studies of Man's Mobility in Space and on the Moon

1969 ◽  
Vol 11 (5) ◽  
pp. 419-431 ◽  
Author(s):  
Donald E. Hewes
Keyword(s):  
Lunar Surface ◽  
Space Station ◽  
Space Missions ◽  
Space Suit ◽  
Reduced Gravity ◽  
Research Facility ◽  
Lunar Landing ◽  
Propulsion Unit ◽  
Langley Research Center ◽  
Space Activities

A brief review of some reduced-gravity simulators recently developed at NASA's Langley Research Center to study specific problems relating to man's mobility in various space missions is presented in this paper along with a discussion of the manner in which these devices can be applied to other mobility problems. The devices covered in this review are the lunar walking simulator, the rotating space station simulator, and the lunar landing research facility being utilized by the Spacecraft Research Branch of LRC. These facilities are applicable to a rather broad field of space activities including such aspects as man walking on the lunar surface in a pressurized space suit, flying over the lunar surface with a backpack propulsion unit or a small rocket-propelled vehicle, driving a surface roving vehicle, and orbital assembly of spacecraft components. These facilities can also be applied to studies of space missions on other planets, moons, and asteroids.

Features of slopes overcoming by walking devices

2021 ◽  
Vol 9 (3) ◽  
pp. 234-240
Author(s):  
Vadim Chernyshev ◽  
Vladimir Arykantsev ◽  
Anton Goncharov ◽  
Nikolay Sharonov
Keyword(s):  
Mobile Robots ◽  
Experimental Studies ◽  
Field Tests ◽  
Soil Conditions ◽  
Adhesion Properties ◽  
Walking Machines ◽  
Volgograd Region ◽  
Propulsion Unit ◽  
Force Characteristics ◽  
Robot Body

For mobile robots designed to work in extreme conditions, an important characteristic is the value of the overcoming slope. For wheeled and tracked vehicles, the angle of the overcoming slope is limited by the adhesion properties of the soil. The walking device can provide overcoming of higher slopes, since the analogue of the adhesion coefficient for walking machines, with a large footprint track depth, can be significantly greater than 1. The paper discusses the results of experimental studies of the features of overcoming slopes by a walking device in weak soil conditions. When mobile robots overcoming inclines, they may overturn or slide downhill. It is shown that on soft soils the sliding of walking machines downhill is unlikely because of significant deformations of the soil under the support elements. On the other hand, the deformation of the soil worsens the resistance of the walking vehicle to overturning. A method of increasing resistance to overturning by controlling the position of the robot body by separately regulating the conditional clearance of walking mechanisms is considered. The possibility of adjusting the clearance in the propulsion unit on the basis of Umnov-Chebyshev cyclic walking mechanisms is shown. Climbing slopes requires a certain amount of traction. The values of the additional power and the force characteristics of the walking device’s drive necessary for successful overcoming of slopes have been determined. The results of the work can be demand in the development of walking machines and mobile robots. Key words Mobile robots, walking machines, interaction with the ground, traction and coupling properties, overcoming slopes, tipping resistance, mathematical modeling, field tests. Acknowledgements Research was partially supported by RFBR and the Administration of the Volgograd region, research projects no. 19-08-01180 a, 19-48-340007 p_a.

Sign in / Sign up

Export Citation Format

Share Document