scholarly journals Design of Inward-Turning External Compression Supersonic Inlet for Supersonic Transport Aircraft

INSIST ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 104
Author(s):  
Muhammad Adnan Utomo ◽  
Romie Oktavianus Bura
Keyword(s):  
Cfd Simulation ◽  
Design Method ◽  
Low Noise ◽  
Design Tool ◽  
Flow Distortion ◽  
External Compression ◽  
Cross Sectional ◽  
Minimum Requirement ◽  
Inlet Geometry ◽  
The Military

Inward-turning external compression intake is one of the hybrid intakes that employs both external and internal compression intakes principle. This intake is commonly developed for hypersonic flight due to its efficiency and utilizing fewer shockwaves that generate heat. Since this intake employ less shockwaves, this design can be applied for low supersonic (Mach 1.4 - 2.5) intakes to reduce noise generated from the shockwaves while maintaining the efficiency. Other than developing the design method, a tool is written in MATLAB language to generate the intake shape automatically based on the desired design requirement. To investigate the intake design tool code and the performance of the generated intake shape, some CFD simulation were performed. The intake design tool code can be validated by comparing the shockwave location and the air properties in every intake's stations. The performance parameters that being observed are the intake efficiency, flow distortion level at the engine face, and the noise level generated by the shockwaves. The design tool written in MATLAB is working as intended. Two dimensional axisymmetric CFD simulations validation has been done and the design meets the minimum requirement. As for the 3D inlet geometry, with a little modification on diffuser and equipping vent to release the buildup pressure, the inlet has been successfully met the military standard on inlet performance (MIL-E-5007D). This design method also has feature to fit every possible throat cross sectional shapes and has been proven to work as designed.Keywords— Inward-turning, Supersonic, Engine Intakes, Low- noise, Design Method

Study on Overall Design of a Vertical Take-Off and Landing Unmanned Aerial Vehicle Powered by Electric Ducted Fans

2021 ◽  
Author(s):  
Tawei Chou ◽  
Qiyu Ying ◽  
Yuping Qian ◽  
Weilin Zhuge ◽  
Yangjun Zhang
Keyword(s):  
Power Unit ◽  
Unmanned Aerial Vehicle ◽  
Cfd Simulation ◽  
Design Method ◽  
Load Capacity ◽  
Design Procedure ◽  
Low Noise ◽  
Overall Design ◽  
Ducted Fan ◽  
Aerial Vehicle

Abstract Facing the growing traffic fleet in the cities nowadays, it is believed that three-dimensional urban transportation could be a solution and will be introduced in the near future. Vertical take-off and landing flying platforms powered by ducted fans will attract increasingly attention because it has advantages on high propulsion efficiency, low noise, and better safety. However, unlike traditional open-blade multi-rotor drones, ducted fan drones lack a systematic design approach that comprehensively considers the overall system performance and the power unit efficiency. Current design procedure leads to insufficient load capacity and low efficiency systems. This paper proposes an overall design method for a ducted fan-type vertical take-off and landing flight platform. The ducted fan and motor of the core power unit are designed and selected aiming at improving aerodynamic efficiency and structural utilization of the system. A heavy-load vertical take-off and landing Unmanned Aerial Vehicle (UAV) powered by ducted fans with a take-off weight of 450kg is designed based on this method. CFD simulation is utilized to calculate the performance of the designed Unmanned Aerial Vehicle, and finite element analysis is carried out to examine the overall strength safety. The final design results show that the overall design method plays a great role in the development of ducted fan UAV.

Fan Blade Selection for Low Noise Part 1: Design Philosophy

1989 ◽  
Vol 203 (3) ◽  
pp. 149-154
Author(s):  
N Hay ◽  
J S B Mather ◽  
R Metcalfe
Keyword(s):  
Design Method ◽  
Separated Flow ◽  
Low Noise ◽  
Broadband Noise ◽  
Test Results ◽  
Flow Distortion ◽  
Acoustic Performance ◽  
Design Philosophy ◽  
Fan Blade ◽  
Lifting Surfaces

It has been known for many years that the broadband noise of rotating machinery is dependent on the condition of the boundary layers on the lifting surfaces. Designs with high efficiencies and clean flow have mainly produced low noise levels. These units have generally used high technology blading, with low inlet velocities and minimal separated flow. In the application of machines in industry, however, many are subject to inlet flow distortion and turbulence. These produce changes to the flow pattern around the blades which may have a relatively insignificant effect on the aerodynamics of the machine but almost completely destroy its acoustic performance. The design method described by Hay, Metcalfe and Reizes (15) allows the designer to pitch the operating point well away from stall. Thus low-response blading can be used for those installations whose flow conditions cannot be improved. This method is further developed in this paper using some correlations from McKenzie's work (17). The application of the method to the design of a low noise fan in the presence of a ±10 per cent perturbation on inlet velocity is given in way of illustration of the approach. In Part 2 of this paper (to be published later) it is hoped to demonstrate the validity of the design philosophy presented here with test results from fans designed according to this philosophy.

scholarly journals PAID – A NOVEL FRAMEWORK FOR DESIGN AND SIMULATION OF ASYNCHRONOUS CIRCUITS

2011 ◽  
Vol 14 (2) ◽  
pp. 37-45 ◽  
Author(s):  
Vu Duc Anh Dinh
Keyword(s):  
Design Method ◽  
Asynchronous Circuits ◽  
Low Noise ◽  
Design Tool ◽  
Clock Signal ◽  
Levels Of Abstraction ◽  
Synchronous Circuits ◽  
High Level ◽  
Local Synchronization ◽  
Asynchronous Circuit Design

Contrary to the synchronous circuits, the asynchronous circuits operate with a mechanism of local synchronization (without clock signal). For many years, they showed their relevance with respect to the synchronous circuits thanks to their properties of robustness, low power, low noise and modularity. However, the lack of design methods and associated tools prevents them from being widely spread. This paper deals with a new design methodology for integrated asynchronous circuits and EDA tools. The suggested design method allows on one hand to model circuits in a highlevel language, and on the other hand to generate circuits using only elementary logical gates and Muller gates. This method was prototyped by the development of an EDA design tool for asynchronous circuits. The combination of design methodologies and supporting tools creates a design framework for asynchronous circuits, namely PAiD ("Project of Asynchronous Circuit Design"). This framework allows compilation and synthesis of circuits, described by high-level language ADL ("Asynchronous Description Language"), to generate asynchronous circuits. The result of the synthesizer is a functional netlist of the circuits. This netlist can be then mapped to a specific-technology gate library for asynchronous circuits. During the design process, the circuit can be tested through the simulation process in different levels of abstraction.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

Development of a New Design Method for High Efficiency Swept Low Pressure Axial Fans With Small Hub/Tip Ratio

2014 ◽  
Author(s):  
Thore Bastian Lindemann ◽  
Jens Friedrichs ◽  
Udo Stark
Keyword(s):  
High Efficiency ◽  
Design Method ◽  
Tangential Velocity ◽  
Pressure Rise ◽  
Low Pressure ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Angle Distribution ◽  
Sweep Angle ◽  
Reduced Pressure

For a competitive low pressure axial fan design low noise emission is as important as high efficiency. In this paper a new design method for low pressure fans with a small hub to tip ratio including blade sweep is introduced and discussed based on experimental investigations. Basis is an empirical axial and tangential velocity distribution at the rotor outlet combined with a distinctive sweep angle distribution along the stacking line. Several fans were designed, built and tested in order to analyze the aerodynamic as well as the aeroacoustic behavior. For the aerodynamic performance particular attention was paid to compensate the influence of reduced pressure rise and efficiency due to increasing blade sweep. This was achieved by a method of increasing the blade chord depending on the local sweep angle which is based on single airfoil data. The tested fans without this compensation revealed a significant noise reduction effect of up to approx. 6 dB(A) for a tip sweep angle of 64° which was accompanied by an unsatisfactory effect of reduced overall aerodynamic performance. The second group of fans did not only confirm the method of the aerodynamic compensation by a nearly unchanged pressure rise and efficiency characteristic but also revealed an increased aeroacoustic benefit of in average 9.5 dB(A) compared to the unswept version. Beside the overall characteristics the individual differences between the designs are also discussed using results of wall pressure measurements which show some significant changes of the blade tip flow structure.

Study on the Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump With Staggered Blades

2018 ◽  
Author(s):  
Qian-qian Li ◽  
Da-zhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Low Noise ◽  
Living Environment ◽  
Centrifugal Impeller ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Vibration Performance

Due to the distinctive characteristic of massive flow rates, double-suction centrifugal pump has been extensively applied in lots of perspectives, such as drainage, irrigation, transportation projects and other hydraulic engineering realms. Nevertheless, the significance of the pressure fluctuation inside the double-suction centrifugal pump, which is getting more and more prominent under the soaring demands for low noise and comfortable living environment, could not be underestimated. Consequently, how to reduce the pressure fluctuation as far as possible and enhance the running stability of the pump is always the research hotspot. In this study, the double-suction centrifugal impeller with abominable vibration performance is redesigned to improve the internal flow and reduce the flow-induced noise. What’s addition, the two redesigned impellers wearing splitter blades were compared in staggered arrangement with different angles for the purpose of ulteriorly decreasing the pressure fluctuation. On the basis of Realizable k-ε model and SIMPLEC algorithm, the unsteady Reynolds-averaged Navier-Stokes equations (URANS) were resolved by means of CFD simulation and the flow performance and the vibration performance were validated with the experiments. The results illustrate that the redesigned impeller with multi-blade could raise the hydraulic performance and reduce the pressure fluctuation inside the pump. When the impeller of each side was laid with the staggered angle of 12 degrees, the pressure distribution tended to be more uniform and the pressure fluctuation was well ameliorated. Through the pressure fluctuation analysis in time domain and frequency domain, the pressure change inside the pumps could be evaluated quantitatively and accurately, hence different pumps could be contrasted in detail. The consequences of this paper could provide reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps as well as other vane pumps.

Numerical Investigation of the Effect of Diffuser and Volute Design Parameters on the Performance of a Centrifugal Compressor Stage

2016 ◽  
Author(s):  
Lei Yu ◽  
William T. Cousins ◽  
Feng Shen ◽  
Georgi Kalitzin ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Gas Flow ◽  
Pressure Rise ◽  
Design Parameters ◽  
Compressor Stage ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Centrifugal Stage ◽  
And Performance ◽  
The Impact

In this effort, 3D CFD simulations are carried out for real gas flow in a refrigeration centrifugal compressor. Both commercial and the in-house CFD codes are used for steady and unsteady simulations, respectively. The impact on the compressor performance with various volute designs and diffuser modifications are investigated with steady simulations and the analysis is focused on both the diffuser and the volute loss, in addition to the flow distortion at impeller exit. The influence of the tongue, scroll diffusion ratio, diffuser length, and cross sectional area distribution is examined to determine the impact on size and performance. The comparisons of total pressure loss, static pressure recovery, through flow velocity, and the secondary flow patterns for different volute designs show that the performance of the centrifugal compressor depends upon how well the scroll portion of the volute collects the flow from the impeller and achieves the required pressure rise with minimum flow losses in the overall diffusion process. Finally, the best design is selected based on compressor stage pressure rise and peak efficiency improvement. An unsteady simulation of the full wheel compressor stage was carried out to further examine the interaction of impeller, diffuser and the volute. The unsteady flow interactions are shown to have a major impact on the performance of the centrifugal stage.

scholarly journals Hardware Implementation of FTC of Induction Machine on FPGA

2017 ◽  
Vol 20 (2) ◽  
pp. 76
Author(s):  
S. Boukadida ◽  
S. Gdaim ◽  
A. Mtibaa
Keyword(s):  
Digital Signal Processor ◽  
Fault Tolerant ◽  
Design Method ◽  
Direct Torque Control ◽  
Induction Machine ◽  
Digital Signal ◽  
Design Tool ◽  
Torque Control ◽  
Algorithm Efficiency ◽  
Comparison Results

In this paper, a new design method of Direct Torque Control using Space Vector Modulation (DTC-SVM) of an Induction Machine (IM), which is based on Fault Tolerant Control (FTC) is proposed. Due to its complexity, the FTC implemented on a microcontroller and a Digital Signal Processor (DSP) is characterized by a calculating delay. To solve this problem, an alternative digital solution is used, based on the Field Programmable Gate Array (FPGA), which is characterized by a fast processing speed. However, as an FPGAs increase in size, there is a need for improved productivity, and this includes new design flows and tools. Xilinx System Generator (XSG) is a high-level block-based design tool that offers bit and cycle accurate simulation. This tool can automatically generate the Very High-Density Logic (VHDL) code without resorting to a tough programming, without being obliged to do approximations and more we can visualize the behavior of the machine before implementation which is very important for not damage our machine. Simulation and experimental results using Hardware In the Loop (HIL) of the FTC based DTC-SVM is compared with those of the conventional DTC. The comparison results illustrate the reduction in the torque and stator flux ripples. Our purpose is to reveal our algorithm efficiency and to show the Xilinx Virtex V FPGA performances in terms of execution time. 

scholarly journals New Media and Crime among Adolescents in Anaocha LGA of Anambra Nigeria

2021 ◽  
pp. 65-78
Author(s):  
Chelsea C. Adogu ◽  
Henry N. Chineke ◽  
Prosper O. U. Adogu ◽  
Chika F. Ubajaka ◽  
Amara F. Chizoba ◽  
...  
Keyword(s):  
New Media ◽  
Media Use ◽  
Design Method ◽  
Simple Random Sampling ◽  
Psychological Trauma ◽  
Major Effect ◽  
Cyber Bullying ◽  
Cross Sectional ◽  
Anambra State ◽  
Media And Crime

New media use has been recently understood as an important issue to be looked into among adolescents, parents and others who deal with adolescents. This study sought to examine the new media and crime among adolescents in Anaocha Local Government Area of Anambra State. The study employed the cross-sectional descriptive design method involving a quantitative approach which included a survey of 224 adolescents between the ages of 13-19 years selected by cluster and simple random sampling techniques from five communities in the LGA. The instrument for data collection was interviewer-administered questionnaire while the Statistical Packages for Social Sciences (SPSS) was used in analyzing the data.  Findings revealed that phones were the most prevalent new media in use among adolescents particularly the male ones. Also, majority expressed negative view about the influence of the new media on adolescents, with sexting and cyber-bullying as the most common crimes associated with new media. Furthermore, psychological trauma was identified as the major effect of cyber-bullying on adolescent victims. This study recommended enlightenment of adolescents and other stakeholders in order to curtail the level of crimes committed through the new media. Parents and significant others are advised to keep a close watch on their adolescent children and wards while they are browsing the internet, and this will hopefully control criminal activities associated with new media use among adolescents in Anaocha LGA in particular and Nigeria in general.

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