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Research Of Extinction Tomography Technique And It's Application In Gas-particles Flow Measurement

Posted on:2005-11-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:1118360122992499Subject:Control theory and control engineering
Abstract/Summary:PDF Full Text Request
Extinction Tomography technique is a new Process tomography(PT) technique which is presented and developed recently. It amalgamates the optical measurement technology and the theory of image reconstruction from projection, reconstructs the some parameters distribution of measured field through the modulated effect of measured matter to the light. This paper explored the theory and technology of the extinction tomography, and it's applications in the measurement of gas-particle two-phase flow. On the base of the related research achievement, the structure and characteristics of annular fan beam sensor, principle of light scanning,image reconstruction,image explanation and system frequency domain analysis are thoroughly researched. There will be a helpful exploration for developing and utilizing the novel optical measurement technique.The project explored in this paper will provide a good application foreground in the field as control, measurement,forecast and saving energy of production process.The related work and harvest in this paper as follows:1. The modified effect of light in particles flow is described according to the theory of extinction light (Law of Lambert-bear), moreover, the Radon Transform formula is educed according to light scanning principle, so the inverse problem of extinction tomography is elicited.2. The design thought of annular fan beam sensor structure is presented, and array laser sensor of 15x5 fan beams structure was developed. The sensor's measurement sensitivity distribution and spatial resolution are analyzed and calculated.3. The image reconstruction algorithms is thoroughly researched. The Filter Back Projection(FBP), Algebra Reconstruction Technology(ART) and fan beam data rearrangement algorithm used in medical computer tomography are improved. The NOSER algorithm, linear neural networks method and Hopfield neural networks method are presented and gain the better result of image reconstruction.4. The image explanation is performed by way of advanced information processing technology. The automatic identification techniques of two phase flowregime in the pipe are researched based on image explanation, as well as the calculation model of average concentration and mass flowrate of flowing particles.5. The extinction tomography system are synthesizilly analyzed in frequency domain. The influence of uncompleted projection data and image construction algorithm to the image quality is researched too.6. The simulation experimental equipment of gas-particles flow in upright pipe are established, moreover, the dynamic observation of flow regime, the measurement of concentration and mass flowrate of quartz grain flow ware performed in the experiment, the results show the feasibility of this new optical measurement technology.
Keywords/Search Tags:Optical tomography, Extinction theory, Inverse problem, Image reconstruction, Gas-particle two phase flow, Mass flowrate, Concentration distribution, Flow regime
PDF Full Text Request
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