A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron ...A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron microscopy were used to analyze its morphologies and microstructures. The results show that the microstructures of the pipe blank are homogeneous and the precipitates are uniformly distributed d 25～70 nm spherical or sphere like Al 12 (Fe,V) 3Si particles, its mechanical properties at room temperature and 350 ℃ after densification by extrusion are σ b=412 MPa, δ =7.6% and σ b=187 MPa, δ =7.6%, respectively. The analyses indicate that the proper match of the motion rates of atomizer and substrate can produce deposited blanks with uniform thickness and relatively high cooling rate.展开更多
In this paper,the visualization of the thermo-hydrodynamic behavior in flat-plate pulsating heat pipe(FP-PHP)with HFE-347 is experimentally investigated.The FP-PHP is vertically placed with filling rate of 20%to 70%an...In this paper,the visualization of the thermo-hydrodynamic behavior in flat-plate pulsating heat pipe(FP-PHP)with HFE-347 is experimentally investigated.The FP-PHP is vertically placed with filling rate of 20%to 70%and heating power of 20 W to 140 W.A high-speed camera is used to record the two-phase flow in the FP-PHP.Four flow pattern types and four flow directions are observed.The flow directions of the two-phase flow inside the FP-PHP with medium filling rate(40%–60%)are the most complex,and the FP-PHP with high filling rate(70%)is most likely to form a directional circulating flow.At high heating power(100 W to 140 W),the flow patterns in FP-PHP with medium(40%–60%)and high filling rate(70%)are dominated by mixed flow.The wall temperature fluctuates greatly at moderate heating power(60 W to 80 W)owing to the uncertainty of the flow direction.The temperature distribution of the FP-PHP is highly affected by the heat transfer intensity of the working fluid under different flow states,so that the state of fluid flow and the thermal performance of FP-PHP can be evaluated through the infrared thermal image of the FP-PHP.展开更多
介绍了中国计量科学研究院新研制的两台高精度钠热管固定点炉(SHPF-1、SHPF-2),并测量了其垂直温场.当这两台钠热管固定点炉的炉温分别控制在比铝凝固点低约2℃、3℃时,铝点容器温度计阱底部150 mm范围内温场均匀性分别为15 mK和11 mK,...介绍了中国计量科学研究院新研制的两台高精度钠热管固定点炉(SHPF-1、SHPF-2),并测量了其垂直温场.当这两台钠热管固定点炉的炉温分别控制在比铝凝固点低约2℃、3℃时,铝点容器温度计阱底部150 mm范围内温场均匀性分别为15 mK和11 mK,并与国外同类的钠热管固定点炉的技术指标进行比较.此外,分析了影响固定点炉等温性能的因素.
Abstract：
Two sodium heat-pipe fixed point furnaces (SHPF-1, SHPF-2) developed at the National Institute of Metrology (NIM) are described, and their vertical temperature uniformities are measured. When the temperatures of the these two furnaces are controlled about 2 ℃ and 3 ℃ respectively, below the freezing point of the aluminum, the largest temperature differences did not exceed 15 mK and 11 mK in a distance about 150mm along the reentrant well of the aluminum point cell, respectively. These temperature uniformities are compared with those of foreign similar sodium heat pipe furnaces. Additionally, factors influencing isothermal characteristics of fixed point furnaces are analyzed.展开更多
将Zn-3Al焊料片置于6063铝合金待焊内外管材径向间隙中,采用磁脉冲预成形技术成形铝合金待焊接头,然后使用高频感应加热装置对预成形后的待焊接头进行了钎焊连接。研究了不同放电电压、管材间隙及钎料片厚度对磁脉冲预成形铝合金待焊接...将Zn-3Al焊料片置于6063铝合金待焊内外管材径向间隙中,采用磁脉冲预成形技术成形铝合金待焊接头,然后使用高频感应加热装置对预成形后的待焊接头进行了钎焊连接。研究了不同放电电压、管材间隙及钎料片厚度对磁脉冲预成形铝合金待焊接头的结合性能、均匀性系数及成形状态的影响,并对比分析了不同钎焊温度时接头的界面冶金结合状态及显微形貌。结果表明,在放电电压12 k V、管件间隙1.5 mm、钎料片150μm时得到的待焊接头具有良好的外观、管件贴合度及结合强度;在420℃钎焊5 s获得的钎焊接头,其界面结合效果好,在钎料合金与铝母材结合面形成了连续的元素扩散层,钎料层中无任何孔洞及裂纹等焊接缺陷。钎料层由α-Al先共晶相和细小均匀的Zn-Al共晶相组成。展开更多
文摘A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron microscopy were used to analyze its morphologies and microstructures. The results show that the microstructures of the pipe blank are homogeneous and the precipitates are uniformly distributed d 25～70 nm spherical or sphere like Al 12 (Fe,V) 3Si particles, its mechanical properties at room temperature and 350 ℃ after densification by extrusion are σ b=412 MPa, δ =7.6% and σ b=187 MPa, δ =7.6%, respectively. The analyses indicate that the proper match of the motion rates of atomizer and substrate can produce deposited blanks with uniform thickness and relatively high cooling rate.
基金financial support provided by National Natural Science Foundation of China(Project No.51506033)Guangxi Natural Science Foundation(Grant No.2017JJA160108)Guangxi Colleges and Universities Program of Innovative Research Team and Outstanding Talent。
文摘In this paper,the visualization of the thermo-hydrodynamic behavior in flat-plate pulsating heat pipe(FP-PHP)with HFE-347 is experimentally investigated.The FP-PHP is vertically placed with filling rate of 20%to 70%and heating power of 20 W to 140 W.A high-speed camera is used to record the two-phase flow in the FP-PHP.Four flow pattern types and four flow directions are observed.The flow directions of the two-phase flow inside the FP-PHP with medium filling rate(40%–60%)are the most complex,and the FP-PHP with high filling rate(70%)is most likely to form a directional circulating flow.At high heating power(100 W to 140 W),the flow patterns in FP-PHP with medium(40%–60%)and high filling rate(70%)are dominated by mixed flow.The wall temperature fluctuates greatly at moderate heating power(60 W to 80 W)owing to the uncertainty of the flow direction.The temperature distribution of the FP-PHP is highly affected by the heat transfer intensity of the working fluid under different flow states,so that the state of fluid flow and the thermal performance of FP-PHP can be evaluated through the infrared thermal image of the FP-PHP.
文摘介绍了中国计量科学研究院新研制的两台高精度钠热管固定点炉(SHPF-1、SHPF-2),并测量了其垂直温场.当这两台钠热管固定点炉的炉温分别控制在比铝凝固点低约2℃、3℃时,铝点容器温度计阱底部150 mm范围内温场均匀性分别为15 mK和11 mK,并与国外同类的钠热管固定点炉的技术指标进行比较.此外,分析了影响固定点炉等温性能的因素.
Abstract：
Two sodium heat-pipe fixed point furnaces (SHPF-1, SHPF-2) developed at the National Institute of Metrology (NIM) are described, and their vertical temperature uniformities are measured. When the temperatures of the these two furnaces are controlled about 2 ℃ and 3 ℃ respectively, below the freezing point of the aluminum, the largest temperature differences did not exceed 15 mK and 11 mK in a distance about 150mm along the reentrant well of the aluminum point cell, respectively. These temperature uniformities are compared with those of foreign similar sodium heat pipe furnaces. Additionally, factors influencing isothermal characteristics of fixed point furnaces are analyzed.
文摘将Zn-3Al焊料片置于6063铝合金待焊内外管材径向间隙中,采用磁脉冲预成形技术成形铝合金待焊接头,然后使用高频感应加热装置对预成形后的待焊接头进行了钎焊连接。研究了不同放电电压、管材间隙及钎料片厚度对磁脉冲预成形铝合金待焊接头的结合性能、均匀性系数及成形状态的影响,并对比分析了不同钎焊温度时接头的界面冶金结合状态及显微形貌。结果表明,在放电电压12 k V、管件间隙1.5 mm、钎料片150μm时得到的待焊接头具有良好的外观、管件贴合度及结合强度;在420℃钎焊5 s获得的钎焊接头,其界面结合效果好,在钎料合金与铝母材结合面形成了连续的元素扩散层,钎料层中无任何孔洞及裂纹等焊接缺陷。钎料层由α-Al先共晶相和细小均匀的Zn-Al共晶相组成。
