长微直管内气体低速流动的亚堵塞现象  

Sub-choking phenomenon of low-speed gas flow in a long-constant-area microchannel

作　　者：丁英涛[1] 何枫[1] 姚朝晖[1] 沈孟育[1] 王学芳[1] 

机构地区：[1]清华大学工程力学系,北京100084

出　　处：《物理学报》2004年第8期2429-2433,共5页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 2 72 0 66)资助的课题~~

摘　　要：长微直管道内多流态并存的流动特性研究不仅有理论意义 ,而且在太空飞行器的控制系统中有着重要的应用价值 .采用实验研究和理论模型近似分析相结合的方法研究了长微直管道内的气体流动特性 .实验中 ,以空气为工作介质 ,进口压力分别设定为 1 30 ,2 5 0 ,32 0kPa ,出口压力变化范围为 9— 1 0 0kPa .沿程分布有五个测压点 ,进出口设有温度传感器 ,测量出口流量的同时可以得到沿程压力分布 .近似理论模型采用二维平板近似模型 .研究发现 ,在保持进口压力不变、不断降低出口压力的条件下 ,当进出口压比低于 5 .3左右时 ,质量流量随压比增加而增加 ;当进出口压比高于 5 .3左右后 ,微管道内流动的质量流量随压比的增加变化很小 ,基本上趋近于某个常数 ,并且出口处的压力扰动波很难向上游传播 .将此现象定义为亚堵塞现象 ,并将发生该现象时对应的进出口压比定义为亚堵塞临界压比 .同时进一步研究了亚堵塞现象与S V(表面积与体积比 )The study on gas flow characteristics in a long_constant_area microchannel in mixed Kn _regime flows has not only theoretical meaning, but also important application in controlling the system of outer space aerocrafts. Flow characteristics were studied based on experiments and approximate theoretical analysis. The inlet pressure was 130, 250 and 320?kPa, and the outlet pressure ranged from 9 to 100?kPa. Five pressure measuring points were distributed along the microchannel and the temperature sensors were located at the inlet and outlet. The pressure distribution and the volume flow rate of air were measured experimentally. An approximate theoretical model based on Poiseuille flow was adopted. Experimental investigations with the long_constant_area microchannel indicate that the mass flow rate through the microchannel changes little as the inlet_to_outlet pressure ratio reaches a certain critical value. The phenomenon is defined as sub_choking and the corresponding pressure ratio is defined as the sub_choking_critical_pressure_ratio. The phenomenon of sub_choking is due to the surface effects. Moreover, the effects of the ratio of surface to volume on the critical pressure ratio are studied.

关 键 词：长微直管道 亚堵塞 多流态并存 临界压比 流体力学 

分 类 号：O354[理学—流体力学]