Dissertation > Excellent graduate degree dissertation topics show

Method for measuring the void fraction of gas-liquid two-phase flow

Author: GongYiMing
Tutor: KongDeRen; ShangFei
School: Nanjing University of Technology and Engineering
Course: Precision instruments and machinery
Keywords: ERT ramjet porosity measurements FPGA current source
CLC: TP274
Type: Master's thesis
Year: 2014
Downloads: 17
Quote: 0
Read: Download Dissertation

Abstract


The ramjet of gas-liquid two-phase flow underwater generates a lot of bubbles, the mixture of gas and liquid will generate the gas-liquid two-phase flow. The porosity reflects the area of the gas-liquid two-phase flow in the tube of one section at a certain time, the value of the porosity reflects the working performance of the ramjet. The accurate measurement of the porosity has important significance on development and performance of the ramjet.Porosity has various measurement methods, the new measurement technology based on the the ERT measurement principle has non-ablative, high security, simple structure, fast response speed and real-time visualization. This paper developed a set of real-time measurement system with12electrodes, aiming at continuous phase conducting medium, based on the analysis of the existing ERT measurement method.Traditional ERT measurement system only has1.4kΩ load capacity, which cannot satisfy the working environment requirement of the gas-liquid two-phase ramjet. Based on the improved constant current source design method, this paper used bipolar pulse current as excitation signal, realized the system load capacity reaching10kΩ, expanded the measuring range of ERT system.As the core controller of the system, the FPGA realized the system’s logic control, excitation signal generation, data acquisition, data reading and PC communications. In hardware circuit, through the control of the excitation signal generating circuit of bipolar current, electrode array gating circuit, programmable amplifier circuit, data acquisition circuit1, it realized conductivity measurement of the water ramjet multiphase flow.Based on quartus Ⅱ software development platform, we use VHDL language programming, achieving module design such as key debounce, direct exchange switch, electrode switching, programmable amplifier, AD acquisition and so on. Through programmable amplifier module, gain can be adjusted from0.08to10000by itself. Meanwhile, we adopt multiple sampling at separated time, eliminating DC component of signal and improving real-time performance of system.Through system calibration experiments, channel conformance test experiments, verification experiment simulated environment,we analyze and verify the performance of Digital ERT system. Experimental results show that every index of the system can content two-phase flow measurement which underwater ramjet produced.

Related Dissertations

  1. Research on Electromagnetic Acoustic Transducer Detection System Based on FPGA,TH878.2
  2. Study on Drive and Control System of Five-Phase PMSM Based on FPGA,TM341
  3. Development of LXI Arbitrary Waveform Generator,TM935
  4. Design of Digital Predistorter for RF Power Amplifier Based on FPGA,TN722.75
  5. Synchronization and Channel Estimation Algorithm in Bursted OFDM System and Its Implementation on FPGA,TN919.3
  6. Performance Analysis of Anti-Multipath Capability in DSSS System and Study on the Compensation Methods,TN914.42
  7. Optimizing and Realising Research on Vedio Compression in TV Guidance System,TN919.81
  8. Research and Hardware Simulation of Multiuser Spread Spectrum Code Acquisition Based on FPGA,TN914.42
  9. Research on Basic Algorithms of Digital Image Processing and Implementation with FPGA,TP391.41
  10. Research of High Speed Image Pre-processing System Based on FPGA,TP391.41
  11. Design of High-Speed Digital Image Acquisition and Interface Based on FPGA,TP274.2
  12. Development of Inductance Sensor Data Acquisition System Based on FPGA,TP274.2
  13. Development of Serial Bus Analyzer Based on Nios,TP274
  14. Development of PMC High-speed Data Transmission Board Design Based on FPGA-RocketIO_X,TP274.2
  15. Development of Pxibus High Performance Digital I/O Module,TP274
  16. Development of LXI Counter,TP274
  17. A High-Speed and Real-Time Data Acquisition System Based on FPGA,TP274.2
  18. Design of GPS Information Receiving System Based on Nios Ⅱ,TN967.1
  19. Temperature and pressure explosives temperature field memory test technology,TQ560.7
  20. Erbium-doped fiber amplifier pump laser drive source research applications,TN248
  21. Remote FPGA system design and implementation of security upgrades,TP309

CLC: > Industrial Technology > Automation technology,computer technology > Automation technology and equipment > Automation systems > Data processing, data processing system
© 2012 www.DissertationTopic.Net  Mobile