Inverse heat conduction method (IHCM) is one of the most effective approaches to obtaining the boiling heat transfer coefficient from measured results. This paper focuses on its application in cryogenic boiling heat t...Inverse heat conduction method (IHCM) is one of the most effective approaches to obtaining the boiling heat transfer coefficient from measured results. This paper focuses on its application in cryogenic boiling heat transfer. Experiments were conducted on the heat transfer of a stainless steel block in a liquid nitrogen bath, with the assumption of a 1D conduction condition to realize fast acquisition of the temperature of the test points inside the block. With the inverse-heat conduction theory and the explicit finite difference model, a solving program was developed to calculate the heat flux and the boiling heat transfer coefficient of a stainless steel block in liquid nitrogen bath based on the temperature acquisition data. Considering the oscillating data and some unsmooth transition points in the inverse-heat-conduction calculation result of the heat-transfer coefficient, a two-step data-fitting procedure was proposed to obtain the expression for the boiling heat transfer coefficients. The coefficient was then verified for accuracy by a comparison between the simulation results using this expression and the verifying experimental results of a stainless steel block. The maximum error with a revised segment fitting is around 6%, which verifies the feasibility of using IHCM to measure the boiling heat transfer coefficient in liquid nitrogen bath.展开更多
低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用一些永磁材料,如钕铁硼(Nd Fe B)或镨铁棚(Pr Fe B)的磁场性能在低温下明显高于室温的特性来提高波荡器性能和光源束流品质,工作...低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用一些永磁材料,如钕铁硼(Nd Fe B)或镨铁棚(Pr Fe B)的磁场性能在低温下明显高于室温的特性来提高波荡器性能和光源束流品质,工作温区为50-150 K,需要冷却系统的冷却。CPMU冷却系统主要包括过冷液氮冷却系统和磁体阵列冷却回路。本文介绍了上海光源(Shanghai Synchrotron Radiation Facility,SSRF)CPMU过冷液氮冷却系统的设计方案和设计参数,进行了系统主要热负载的分析;对冷却系统中关键设备之一的过冷换热器进行了设计,并计算分析了过冷氮流经CPMU冷却系统的全程阻力损失,为系统另一关键设备液氮泵的选型提供依据。对CPMU过冷液氮冷却系统进行的在线测试表明,该设计满足CPMU样机的冷却需求。展开更多
针对某厂液氮洗工艺进行改造,进行常温进料,突破原料气来自低温甲醇洗的限制。提出了3种改良方案,分别为减少板翅式换热器数量(方案Ⅰ、Ⅱ)和增设甲烷回收装置(方案Ⅲ),以达到与甲醇洗工艺解偶联、节约设备成本、提高经济效益等目的。使...针对某厂液氮洗工艺进行改造,进行常温进料,突破原料气来自低温甲醇洗的限制。提出了3种改良方案,分别为减少板翅式换热器数量(方案Ⅰ、Ⅱ)和增设甲烷回收装置(方案Ⅲ),以达到与甲醇洗工艺解偶联、节约设备成本、提高经济效益等目的。使用Aspen Plus和Aspen Process Economic Analyzer软件进行模拟优化,结果显示,常温进料液氮洗工艺及其改良方案均符合工艺要求,方案Ⅰ可节约成本达45.78%,方案Ⅲ可回收甲烷达99.16%,为常温进料液氮洗工艺在实际生产中应用指明方向,为优化工艺设计、节约设备成本、提高经济效益提供理论指导。展开更多
基金supported by the National Natural Sciences Foundation of China (No. 50776075)
文摘Inverse heat conduction method (IHCM) is one of the most effective approaches to obtaining the boiling heat transfer coefficient from measured results. This paper focuses on its application in cryogenic boiling heat transfer. Experiments were conducted on the heat transfer of a stainless steel block in a liquid nitrogen bath, with the assumption of a 1D conduction condition to realize fast acquisition of the temperature of the test points inside the block. With the inverse-heat conduction theory and the explicit finite difference model, a solving program was developed to calculate the heat flux and the boiling heat transfer coefficient of a stainless steel block in liquid nitrogen bath based on the temperature acquisition data. Considering the oscillating data and some unsmooth transition points in the inverse-heat-conduction calculation result of the heat-transfer coefficient, a two-step data-fitting procedure was proposed to obtain the expression for the boiling heat transfer coefficients. The coefficient was then verified for accuracy by a comparison between the simulation results using this expression and the verifying experimental results of a stainless steel block. The maximum error with a revised segment fitting is around 6%, which verifies the feasibility of using IHCM to measure the boiling heat transfer coefficient in liquid nitrogen bath.
文摘针对某厂液氮洗工艺进行改造,进行常温进料,突破原料气来自低温甲醇洗的限制。提出了3种改良方案,分别为减少板翅式换热器数量(方案Ⅰ、Ⅱ)和增设甲烷回收装置(方案Ⅲ),以达到与甲醇洗工艺解偶联、节约设备成本、提高经济效益等目的。使用Aspen Plus和Aspen Process Economic Analyzer软件进行模拟优化,结果显示,常温进料液氮洗工艺及其改良方案均符合工艺要求,方案Ⅰ可节约成本达45.78%,方案Ⅲ可回收甲烷达99.16%,为常温进料液氮洗工艺在实际生产中应用指明方向,为优化工艺设计、节约设备成本、提高经济效益提供理论指导。
