| 摘要: |
| 用以测量辐射信号的球形实验装置置于直径为43 m、高为44 m的圆柱形实验厅内，球体外侧安装信号接收光电倍增管球壳层（PMTs），其运行会产生200 kW的高热。为维持球体表面水体温度稳定在（21±1）℃高精度恒温环境下，本文采用计算流体力学（CFD）技术，将球体浸没在循环水中并配合上下两段式布水方式进行精准控温。结果表明：上下两段布水方式可实现大型水体空间局部精确控温。考虑到不规则腔体流道限制，设计调整水循环布水角度，上布水口低温面积最大增幅达20%；提出增大上下布水器水量比以控制水体垂直温差，上下布水器水量之比为2.5:1时控温能力最强，且降温最有效的区域是多孔介质PMT层与外水层；为得到不同热量下温度分布的统一规律，增大热源发热量，内水层上下布水口低温面积变化幅度有差异，上布水口低温面积缩小41%，下布水口缩小62%，但下布水口低温面积始终大于上布水口。 |
| 关键词: 发热球体 布水参数 控温技术 数值模拟 |
| DOI： |
| 投稿时间：2020-04-07 修订日期：2020-11-16
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| 基金项目:中央高校基本科研业务费专项资金（22120180567）资助。 |
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| Simulations on a Water Circulating System for a Large-scale Irregular Chamber with Internal Heat Sources for High-precision Temperature Control |
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Xue Yu1, Ye Wei1,2, Zhao Wenxuan1, Wu Chao1, Zhang Xu1
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| (1.School of Mechanical Engineering, Tongji University;2.Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education, Tongji University) |
| Abstract: |
| A spherical experimental device placed in a cylindrical hall of diameter 43 m and height 44 m was used to measure the radiation signal. Photomultiplier tubes (PMTs), which is used to receive the signal, were installed on the exterior surface of the sphere. The PMTs generated heat at 200 kW during operation. To maintain the surface temperature of the sphere at (21±1) ℃, a method for high-precision temperature control by immersing the sphere in circulated water and distributing water up and down simultaneously was proposed. A simulation method using computational fluid dynamics was applied to analyze the temperature field of the water. The results showed that the method of distributing water up and down simultaneously can achieve a precise local temperature control in large spaces. Owing to the limited flow channels in the irregular cavity, the angle of inclination for both upward and downward water distributors of the circulating system was adjusted to improve the performance of temperature control locally. The increase in the area with a low temperature using the upper water distributors can be up to 20%. To reduce the vertical temperature difference of the water, the water flow ratio of the upper and lower water distributors was increased. The temperature requirement can be met when the water flow ratio is 2.5:1.The water volumes that are effectively cooled are the porous media layer and outer water layer. To obtain temperature profiles with an accuracy of (21±1) ℃ under various heating intensities, the heat flux of the heating sources was determined. The variation ranges of the low-temperature volumes around the upper water distributors differed from that around lower water distributors of the inner water layer. The low-temperature volumes around the water distributors at the top decreased by 41%, while the volumes around the distributors at the bottom decreased by 62%. However, the low-temperature volumes around the lower water distributors were larger than those at the upper water distributor, regardless of the amount of heat flux from the heating sources. |
| Key words: sphere heating source water distribution temperature control numerical simulation |
