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电磁轨道炮枢轨的动态焦尔热特性 被引量:10
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作者 耿轶青 刘辉 +1 位作者 马增帅 袁建生 《高电压技术》 EI CAS CSCD 北大核心 2019年第3期799-804,共6页
电磁轨道炮发射过程中会产生大量的热,这些热量导致的效应严重影响着轨道炮寿命及发射效率。为了研究枢轨及其接触面温度场的变化规律,给出了一种在电磁–热–温度瞬态耦合场作用下焦尔热及其温升的数值计算方法,并分析了枢轨的焦尔热... 电磁轨道炮发射过程中会产生大量的热,这些热量导致的效应严重影响着轨道炮寿命及发射效率。为了研究枢轨及其接触面温度场的变化规律,给出了一种在电磁–热–温度瞬态耦合场作用下焦尔热及其温升的数值计算方法,并分析了枢轨的焦尔热及其温升的特性。通过三维轨道炮模型下的有限元数值仿真,首先研究了电磁轨道炮在脉冲波形电流下的电磁场特性;然后计算分析了电枢轨道及枢轨接触面的温度变化。结果表明:电枢的最大电流密度及温度出现在电枢头部内侧拐点位置,其相应产生的温度可达2 000℃以上。枢轨接触面上最大电流密度及温度值始终分布在电枢和轨道的外侧边缘,同时枢轨接触面上的焦尔热对接触面的温升影响很小,且远没有达到枢轨材料熔化的熔点。因此,焦耳热主要对枢轨接触面边缘位置的温升起着重要的作用,但并不会使枢轨接触面的大部分材料发生熔化。 展开更多
关键词 电磁轨道炮 焦尔热 枢轨界面 耦合场 数值仿真
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On-chip fast mixing by a rotary peristaltic micropump with a single structural layer 被引量:3
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作者 DU Min ma zengshuai +1 位作者 YE XiongYing ZHOU ZhaoYing 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第4期1047-1054,共8页
In this work,a rotary pump based micromixer for on-chip rapid mixing and liquid transportation is demonstrated and characterized.Both pumping and mixing are realized using a microfluidic chip with a single structural ... In this work,a rotary pump based micromixer for on-chip rapid mixing and liquid transportation is demonstrated and characterized.Both pumping and mixing are realized using a microfluidic chip with a single structural polydimethylsiloxane layer and a portable electric control system.The rotary pump consists of an annular channel and is driven by a motor and magnets.The flow field caused by the peristaltic movement of the channel membrane of the rotary pump is simulated and analyzed.By statistically calculating and comparing the normalized standard deviations of the flow velocity components in a microchannel,it is revealed that up-and-down mixing is the fastest,followed by segment mixing and parallel mixing.Two mixing styles,segment mixing and parallel mixing,were experimentally demonstrated using the chip.The pump achieved 90% of the mixing index in 1 s for the segment mixing type.As for the parallel mixing type,the mixing index was up to 90% after 5 s,which is more than 100-fold improvement compared to conventional mixing by interfacial diffusion.The mixing speeds in both directions were improved prominently by increasing the rotational speed of the pump. 展开更多
关键词 microfluidic MIXING rotary pump magnetic driving
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