基于Intel8051单片机的医用数字式流量计的设计

非连续滴流流量的测量测定是器官离体灌注保存、静脉注射等临床实际及生物医学实验中经常要碰到的问题 .该类液流具有非连续、小流量的特点 ,滴液之间可能间隔较长的时间且间隔不等 ,常规的各种流量测量技术费用昂贵 ,且体积大 ,还不能很好地解决问题 .本文提出了液位法的测量方法 .利用液位来激发信号 ,再借助于 Intel80 5 1微处理器来解决这一问题 .经使用证明该方法准确性好 ,重复率高 ,测量误差在 - 0 .2 5 %～ + 0 .2 5 %内 。

一种基于孔口出流原理的暴雨测试方法

暴雨是中国主要气象灾害之一,其危害主要包括洪灾和涝渍灾。暴雨是一种影响严重的灾害性天气,因为暴雨在短期内大量聚集,而城市中的排水系统不能及时的将雨水排走,使得大量雨水迅速向城市低洼处汇聚,从而导致各种惨剧。因此,为了给城市建设和工农业生产等提供有力的依据,对暴雨雨量进行较准确的测量,是十分必要的。

Experimental Investigation of Dimensionless Velocity and Shearing Stress in Boundary Layer Flow on Continuous Moving Surface in Power Law Fluids

An analysis is carried out to study the steady flow characteristics from a continuous flat surface moving in a parallel free stream of non-Newtonian power law fluid. The constitutive equations of the fluid are transformed into dimensionless ones. The velocity field is measured by Particle Image Velocimetry. Experimental results are obtained for the distribution of velocity. The influence of wall velocity ratio parameter on boundary layer flow field is observed in the experiment. Dimensionless velocity distribution and shearing stress distribution are obtained by post-processing experimental results. The effects of various physical parameters like velocity ratio parameter and similarity variable on various momentum transfer characteristics are discussed in detail and shown graphically. It is indicated that dimensionless velocity increases with velocity ratio parameter and similarity variable, and that dimensionless shearing stress decreases with velocity ratio parameter and similarity variable.