Electromagnetic performance analysis of the rim electromagnetic direct-driven propeller

2021 ◽  
pp. 095440622199748
Author(s):  
Jian Zhang
Keyword(s):  
Performance Optimization ◽  
Three Dimensional ◽  
Underwater Vehicle ◽  
Test Results ◽  
Three Dimensional Model ◽  
Number Pattern ◽  
And Performance ◽  
Crucial Part ◽  
Electromagnetic Performance ◽  
Computing Models

Propellers are a crucial part to drive underwater vehicles. A rim electromagnetic direct-driven propeller (REDP) had been presented to meet some specific requirements of the underwater vehicle in this paper. It had many advantages compared to classical propellers and could improve the performance of the underwater vehicle. The composition and working mode of REDP were introduced here. In addition, the paper also introduced the working characteristics of REDP and somethings needed to be improved. The energy method was utilized to calculate the distribution of magnetic fields. A three-dimensional model of REDP was built. Then the influence of the propeller’s parameters on performance was analyzed, including the number, pattern, surface radian of the permanent magnet and the stator cogging skew, by finite element computing models. The performances of REDP were tested under several parameters. Some valuable conclusions were obtained according the test results and could provide a reference for the design and performance optimization of REDP utilized on the underwater vehicle.

Digitalization system of ancient architecture decoration art based on neural network and image features

2020 ◽  
pp. 1-12
Author(s):  
Wu Xin ◽  
Qiu Daping
Keyword(s):  
Neural Network ◽  
Construction Industry ◽  
Three Dimensional ◽  
Performance Testing ◽  
Image Features ◽  
Three Dimensional Model ◽  
Performance Effect ◽  
Data Process ◽  
And Performance ◽  
Construction Mode

The inheritance and innovation of ancient architecture decoration art is an important way for the development of the construction industry. The data process of traditional ancient architecture decoration art is relatively backward, which leads to the obvious distortion of the digitalization of ancient architecture decoration art. In order to improve the digital effect of ancient architecture decoration art, based on neural network, this paper combines the image features to construct a neural network-based ancient architecture decoration art data system model, and graphically expresses the static construction mode and dynamic construction process of the architecture group. Based on this, three-dimensional model reconstruction and scene simulation experiments of architecture groups are realized. In order to verify the performance effect of the system proposed in this paper, it is verified through simulation and performance testing, and data visualization is performed through statistical methods. The result of the study shows that the digitalization effect of the ancient architecture decoration art proposed in this paper is good.

scholarly journals Precise point positioning with GPS and Galileo broadcast ephemerides

GPS Solutions ◽  
2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Luca Carlin ◽  
André Hauschild ◽  
Oliver Montenbruck
Keyword(s):  
Precise Point Positioning ◽  
Three Dimensional ◽  
Test Results ◽  
Process Noise ◽  
Functional Models ◽  
Ambiguity Estimation ◽  
Point Positioning ◽  
And Performance ◽  
Range Error ◽  
Space Range

AbstractFor more than 20 years, precise point positioning (PPP) has been a well-established technique for carrier phase-based navigation. Traditionally, it relies on precise orbit and clock products to achieve accuracies in the order of centimeters. With the modernization of legacy GNSS constellations and the introduction of new systems such as Galileo, a continued reduction in the signal-in-space range error (SISRE) can be observed. Supported by this fact, we analyze the feasibility and performance of PPP with broadcast ephemerides and observations of Galileo and GPS. Two different functional models for compensation of SISREs are assessed: process noise in the ambiguity states and the explicit estimation of a SISRE state for each channel. Tests performed with permanent reference stations show that the position can be estimated in kinematic conditions with an average three-dimensional (3D) root mean square (RMS) error of 29 cm for Galileo and 63 cm for GPS. Dual-constellation solutions can further improve the accuracy to 25 cm. Compared to standard algorithms without SISRE compensation, the proposed PPP approaches offer a 40% performance improvement for Galileo and 70% for GPS when working with broadcast ephemerides. An additional test with observations taken on a boat ride yielded 3D RMS accuracy of 39 cm for Galileo, 41 cm for GPS, and 27 cm for dual-constellation processing compared to a real-time kinematic reference solution. Compared to the use of process noise in the phase ambiguity estimation, the explicit estimation of SISRE states yields a slightly improved robustness and accuracy at the expense of increased algorithmic complexity. Overall, the test results demonstrate that the application of broadcast ephemerides in a PPP model is feasible with modern GNSS constellations and able to reach accuracies in the order of few decimeters when using proper SISRE compensation techniques.

Oxygen electrode design criteria and performance characteristics: recessed cathode

1978 ◽  
Vol 45 (1) ◽  
pp. 145-154 ◽  
Author(s):  
G. Schneiderman ◽  
T. K. Goldstick
Keyword(s):  
Measurement Error ◽  
Performance Optimization ◽  
Surrounding Medium ◽  
Three Dimensional ◽  
Concentration Field ◽  
Oxygen Electrode ◽  
Current Sensitivity ◽  
Steady State Operation ◽  
Oxygen Electrodes ◽  
And Performance

A computer simulation of the steady-state operation of recessed (Whalen-type) polarographic oxygen electrodes has been developed to give the design factors important for performance optimization. The simulation makes use of a specially formulated three-dimensional orthogonal coordinate system with the geometry identical to the actual recessed cathode and gives the oxygen concentration field induced by it in the surrounding medium. Equations are presented which allow one to calculate, for any recessed cathode, the current sensitivity, maximum stirring artifact, measurement error, and time constant. Comparisons with analytically obtained expressions for the corresponding quantities for idealized, spherosymmetric cathodes demonstrate the unique aspects of recessed-cathode performance. For commonly used electrodes, a recess length-to-cathode diameter ratio of greater than 10 is found to give a negligible stirring artifact, a negligible measurement error, and a rapid response.

A System of Selective Non Catalytic Reduction of NOx for Diesel Engine

2011 ◽  
Vol 201-203 ◽  
pp. 643-646 ◽  
Author(s):  
Bo Yan Xu ◽  
Hai Ying Tian ◽  
Jie Yang ◽  
De Zhi Sun ◽  
Shao Li Cai
Keyword(s):  
Catalytic Reduction ◽  
Three Dimensional ◽  
Exhaust Gas ◽  
Test Results ◽  
Practical Application ◽  
Three Dimensional Model ◽  
Reduction Efficiency ◽  
Different Temperatures ◽  
Reduction Of Nox ◽  
Good Agreement

SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.

A PROTOTYPE TRACK-FINDING PROCESSOR FOR THE LEVEL-1 TRIGGER OF THE CMS ENDCAP MUON SYSTEM

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1178-1180
Author(s):  
S. M. WANG ◽  
D. ACOSTA ◽  
A. MADORSKY ◽  
B. SCURLOCK ◽  
A. ATAMANCHUK ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Density ◽  
Fringe Field ◽  
Test Results ◽  
Muon System ◽  
Cathode Strip ◽  
Level 1 ◽  
Sram Memory ◽  
And Performance

We report on the development and performance of a novel track-finding processor for the Level-1 trigger of the CMS endcap muon system. The processor links track segments identified in the cathode-strip chambers of the endcap muon system into complete three-dimensional tracks. It then measures the momentum of the best track candidates from the sagitta measured between three muon chambers in the endcap fringe field. The processor is pipelined at 40 MHz, and has an overall latency of 400 ns. The logic for the prototype is implemented in high-density FPGAs and SRAM memory. It receives approximately 3 gigabytes of data every second from a custom backplane operating at 280 MHz. Test results of the prototype are consistent with expectation.

The Simulation Research on Air Drag Reduction of Tail Dome on Vans

2013 ◽  
Vol 345 ◽  
pp. 48-53
Author(s):  
Li Feng Cao ◽  
Xiao Peng Xie ◽  
Jian Hao Zeng ◽  
Heng Huang
Keyword(s):  
Drag Reduction ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Test Results ◽  
Three Dimensional Model ◽  
Simulation Test ◽  
Simulation Research ◽  
Wind Resistance ◽  
Pressure Drag ◽  
Variable Speed Motor

In this paper, three different types of tail domes were designed based on the mechanism of reducing pressure drag between the front and rear of vans, and it takes the van without a dome as a comparison to discuss the drag reduction effects of three different sizes. The three-dimensional model of the van is established in PRO/E, and the pressure and velocity distribution of the van model were analyzed in Fluent; In addition, the wind resistance test of the van model is proceed in the variable speed motor wind resistance simulation test device. The results of CFD simulation have good consistency with the experimental test results, and it verifies the conclusion that the tail dome is good for drag reduction. It provides basis and reference for the optimization of drag reduction for the vans.

scholarly journals Performance Optimization of High Specific Speed Centrifugal Pump Based on Orthogonal Experiment Design Method

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 728 ◽  
Author(s):  
Li ◽  
Ding ◽  
Shen ◽  
Jiang
Keyword(s):  
Centrifugal Pump ◽  
Performance Optimization ◽  
Design Method ◽  
Orthogonal Experiment ◽  
Three Dimensional ◽  
Experiment Design ◽  
Three Dimensional Model ◽  
Pump Design ◽  
Orthogonal Experiment Design ◽  
Specific Speed

A high specific speed centrifugal pump is used in the situation of large flow and low head. Centrifugal pump parameters need to be optimized in order to raise its head and efficiency under off-design conditions. In this study, the orthogonal experiment design method is adopted to optimize the performance of centrifugal pump basing on three parameters, namely, blade outlet width b2, blade outlet angle β2 and blade wrap angle φ. First, the three-dimensional model of the centrifugal pump is established by CFturbo and SolidWorks. Then nine different schemes are designed by using orthogonal table, and numerical simulation is carried out in CFX15.0. The final optimized combination of parameters is b2 = 24 mm, β2 = 24°, φ = 112°. Under the design condition, the head and efficiency of the optimized centrifugal pump are appropriately improved, the increments of which are 0.74 m and 0.48%, respectively. However, the efficiency considerably increases at high flow rates, with an increase of 6.9% at 1.5 Qd. The anti-cavitation performance of the optimized centrifugal pump is also better than the original pump. The results in this paper can provide references for parameter selection (b2, β2, φ) in the centrifugal pump design.

scholarly journals Design and Performance Analysis of Contra-rotating Pumpjet Propulsor under Condition of Torque Unbalance

2018 ◽  
Vol 167 ◽  
pp. 03006
Author(s):  
Xiao-er Wang ◽  
Zhen-shan Zhang ◽  
Meng Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Method ◽  
Three Dimensional ◽  
Underwater Vehicle ◽  
Inverse Design ◽  
Parameter Design ◽  
Power Difference ◽  
Inverse Design Method ◽  
And Performance

In order to balance the torque of front rotor and rear rotor of underwater vehicle, the analysis of the speed triangles at the inlet and outlet of the front and rear rotor has been done. Then, the thought of using contra-rotating pumpjet to achieve the objective was raised. The stator is installed behind the rear rotor so as to ensure the overall torque of the propulsor balance, at the same time, the stator can also support the shroud of the propulsor. the parameter design of the rotor and the stator has been carried out by using the three dimensional inverse design method. At last, the performance of the designed pumpjet propulsor is obtained when it is installed on the underwater vehicle By using computational fluid dynamics. The results show that the total torque of the propulsor is reduced to 1.8 N * m on the design point although the power difference ratio of the front rotor and the rear rotor is 20%. The torque ratio is also reduced from 4.6% to 0.4%, which is good to meet the propulsor balance requirement and verifies the 3-D design method of pumpjet is effective.

Role Ambiguity in Voluntary Sport Organizations

2009 ◽  
Vol 23 (5) ◽  
pp. 615-643 ◽  
Author(s):  
Jesse Sakires ◽  
Alison Doherty ◽  
Katie Misener
Keyword(s):  
Organizational Commitment ◽  
Role Ambiguity ◽  
Three Dimensional ◽  
Performance Outcomes ◽  
Role Clarity ◽  
Sport Organizations ◽  
Organizational Setting ◽  
Three Dimensional Model ◽  
Online Questionnaire ◽  
And Performance

This study examined perceptions and correlates of role ambiguity among sport administrators in voluntary sport organizations. Building on the seminal work of Kahn, Wolfe, Quinn, Snoek, and Rosenthal (1964), a multidimensional measure of role ambiguity in the organizational setting was developed for this purpose. The sample consisted of 79 paid staff and 143 volunteer board members from provincial voluntary sport organizations. Respondents completed an online questionnaire that included items pertaining to role ambiguity, job satisfaction, organizational commitment, effort, and demographic variables including age, gender, position, organization tenure, and position tenure. Preliminary support was found for a three-dimensional model of role ambiguity consisting of scope of responsibilities ambiguity, mean-sends knowledge ambiguity, and performance outcomes ambiguity. Role ambiguity was negatively associated with age, job tenure, and organization tenure, with more years of experience reflecting greater role clarity. Greater role ambiguity was also associated with lower levels of satisfaction, organizational commitment, and effort. In addition, ambiguity pertaining to scope of responsibilities was the primary predictor of both satisfaction and organizational commitment, while performance outcomes ambiguity and means-ends knowledge ambiguity significantly predicted effort. Implications for the management of role ambiguity in voluntary sport organizations, and the merits of a multidimensional approach to understanding this phenomenon, are discussed.

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