| As an effective way to solve the energy crisis,Inertial Confinement Fusion(ICF)has been widely researched around the world.In the ICF experiment,the quality of the ice layer in the LD target is very important.The fuel gas must form a highly uniform,smooth(surface roughness less than 1 μm)and centrosymmetric(sphericity greater than 99%)solid layer on the inner surface of the cryotarget.Compared with deuterium-tritium(DT)ice layer,due to the lack of β decay heat,deuterium-deuterium(DD)ice layer lacks the power of redistribution and self-smoothing.So,it is more difficult to obtain a uniform ice layer in the cryotarget.Based on this,infrared enhanced layering technology of the DD ice layer in the cryotarget is studied in this paper.Accordingly,Forming uniform DD layers in cryotarget using infrared heating has been studied in this paper.Because the DD ice layer has a specific absorption peak in the mid-infrared band,by irradiating infrared light with a wavelength of 3.16 μm,the DD ice layer absorbs energy and produces a volume heating effect.It will promotes the uniform distribution of ice layer.The research contents of this article can be divided into two parts:simulation analysis and preliminary design of experimental system.First of all,an infrared heating simulation mode is created in this paper.The basic idea is to use TracePro to trace the light,and then import the result of the light power distribution absorbed by the target into the Fluent to obtain the temperature distribution.So,the ice layering effect can be get from this result.This article mainly focuses on analyzing the ray tracing part based on TracePro.In order to improve the simulation efficiency,the light field reconstruction algorithm based on ray tracing and TracePro are combined in this paper.,which greatly reduces the simulation time of TracePro.Then,according to the above model,the temperature distribution of the cryotarget in the cylindrical cavity based on the ring light source is researched.The influence of the light source position and the light source power on the ice layering effect are studied in this paper.Then the temperature distribution of the cryotarget in the sphere based on optical fiber illumination is analyzed.And the influence of the light source position and the surface roughness of the sphere on the heating rate distribution of the cryotarget is studied.Finally,the layering effect of the cryotargets under the actual light source position is analyzed.The maximum incident light power when can reach the ice layering requirement is calculated.The temperature distribution of the cryotarget corresponding to the actual infrared light source position is simulated.The maximum power when the ice layer is uniform(the maximum temperature diference on the inner surface of the ice layer is less than 0.1mK)is obtained.In order to study the distribution of ice thickness over time during infrared heating,the backlit shadowgraph method is adopted.The basic principle of the method and the ray tracing model,is studied.Due to the limitation of research time,long cycle of cryotarget parts processing and assembly,etc.,only the preliminary design and construction of the cryotarget infrared layering system has been carried out.The experimental system mainly includes three units,low temperature cooling,infrared heating and backlight projection.An infrared light coupling experiment was carried out to determine the maximum volumetric heating rate of the ice layer that the system can provide.Finally,a preliminary design was made for the specific experiment flow,which is ready for subsequent specific experiments. |
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