| Nuclear energy as a clean source of energy has been widely accepted by the international community. However, the disposal of nuclear waste currently generated by the operation of the reactor is a key problem to be solved. ADS system(accelerator driven sub-critical system) has a wide spectrum, high security features, is one of the most viable means of transmutation long-lived nuclear waste. ADS is a multi-disciplinary research, which include accelerators, spallation target and reactors. Many of the key technical issues need to be resolved, such as neutron physics research, thermal hydraulics, etc. Spallation target is a coupling system of accelerator and subcritical reactors, working in high-temperature and high-radiation environments. When the beam shooting, spallation target will have a very high heat deposition.So it is crucial to study the thermal hydraulics of spallation target.A detailed study for the flow field of the target was carried out by visualization experiments and numerical simulation. Water was used as the working fluid in the experiment. Particle Image Velocimetry(PIV) was applied for visualization of flow field. Computational fluid dynamics analysis was performed by using FLUENT. Five turbulent models(standard k-ε, RNG k-ε, Real k-ε, SST k-ω, RSM)were utilized to calculate the flow at different velocity. The calculated results are given and compared with the experimental data. It is shown that usingRNG k-ε model with the corresponding wall functions can accurately simulate the flow of the window spallation target.Subsequently, using liquid lead-bismuth(LBE) as the working fluid, we have been calculated heat transfer of the spallation target in consideration of the flow field. Defining the target jet aspect ratio H/D as a optimization parameter of spallation target. A preliminary optimization of liquid metal spallation target has been made by using Nu as a measure of heat transfer capability. Such that the heat transfer of the target window be further optimized. |
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