The entrance/exit effects in the current traditional LFMs (Laminar Flow Meter) are unavoidable. LFMs are often designed with a large length-diameter ratio l/d and the consequence is a large pressure loss. A rectangle-gap-type LFM with a laminar flow channel made from the groove between two cubes is proposed and investigated experimentally. The pressure taps located inward the inlet/outlet of the channel replace the original pressure taps that located at the inlet/outlet of channel, so that the rectangle-gap-type LFM can measure the pressure drop from the developed laminar flow to avoid the entrance/exit effects. The results show that the linearity of the rectangle-gap-type LFM is 0.35% for the length-diameter ratio l/d_h=93.5. The deviations are −0.35%~+1.30% in the pressure range 100–500 kPa. The estimated pressure loss coefficients (ζ_ent+ζ_exit) of rectangle-gap-type LFM are only 0.15–0.2, which of traditional LFMs are used to be 1.5. The inward pressure taps allow rectangle-gap-type LFM to adopt a small l/d_h design to achieve low pressure loss measurement. The investigation is of positive significance for improving the performance of LFM.

当前传统的LFM（层流流量计）中的入口/出口效应是不可避免的。LFM经常被设计成具有大的长径比l / d，其结果是很大的压力损失。提出并研究了由两个立方体之间的沟槽构成的层流通道的矩形间隙型LFM。位于通道入口/出口内侧的压力阀取代了位于通道入口/出口处的原始压力阀，因此矩形间隙型LFM可以测量来自层流的压降，从而避免进入/退出效果。结果表明，长径比为l / d _h时，矩形间隙型LFM的线性度为0.35％= 93.5。在100–500 kPa的压力范围内，偏差为-0.35％〜+ 1.30％。所估计的压力损失系数（ζ _ENT + ζ_出口矩形间隙式LFM的）仅0.15-0.2，其中传统的LFMS用于为1.5。向内压力抽头允许矩形间隙式LFM采取小升/ d _ħ设计来实现低的压力损失的测量。该研究对提高LFM的性能具有积极意义。