Research On (137)~Cs γ-ray CT Technology In Measurement Of Gas Holdup In Rushton Gas-liquid Stirring Tank

On the measurement of gas holdup distribution in two-phase flow liquid of Rushton gas-liquid stirring tank, there are already many research reports. Rushton gas-liquid stirring tank are widely used in various industries, the gas-holdup distribution determine the heating transmission, mass trassmission, energy transsmission and chemical reacting. All the measurements on gas-holdup distribution include are the invasive probe measurements, such as electrical conductivity probe, ultrasonic probe method, now the non-invasive, non-contact measurement, such as CT imaging measurement, Laser Doppler Anemometer measurement and Differential pressure measurement method. Gamma-ray Computer Tomography has non-invasive, penetrating power, fast measyrement, and suitable for measuring all kinds of steel vessel with high pressure and temperature, and also has high resolution and accuracy. Originally we used ~137Cs gamma-ray CT to measure in the gas-liquid Rushton Stirring Tank.1. Detailed descriptthe basic circuit of ~137Cs gamma-ray CT for application in gas-liquid stirring tank, design gamma-ray CT scanning method, select the single-source and muti-use detection fan-shaped scanning device, design the gamma ray in the selection, finally ~137Cs energy 662keV, half-life 31 years, radioactivity 100mCi, radiation sffciency of 85.6% for gamma CT.2. The other is the detector, respectively, choose the high detection efficiency, fast response time of NaI scintillator detector for it. To achieve the synchronization of seven detectors, using experimental to fine-tuning threshold of the seven detectors, when the photon energy threshold of 500keV, the synchronization is well, then establish the response function model of homogenization, compare with the experimental data that prove that tne model is feasible.3. Consider the gas cavity structure in Rushton Stirring Tank is fluenced by paddle wheel number, impeller size and speed, gas velocity and so on, include vortex cavities VC, small 3'-3'cavities S33, large 3'-3'cavities L33, ragged cavities RC. Depending the appearance of cavition, take the mathematical model of cavities structure, then calculate the gas-holdup distribution of different cavitations.4. Use ~137Cs gamma-ray CT to measure the gas-holdup distribution under the same conditions with gas cavities structures. In concluding, compared the curve of gas-holdup and non-dimensional radius, the results of the gamma ray CT scan and gas cavities structure calculation are basiclly conformed.