Weldon School of Biomedical Engineering, Department of Basic Medical Sciences, 1426 Lynn Hall, Purdue University, West Lafayette, IN 47907-1246, USA.
Biomed Eng Online. 2010 Aug 31;9:42. doi: 10.1186/1475-925X-9-42.
A valveless pump generates a unidirectional net flow of fluid around a closed loop of soft viscoelastic tubing that is rhythmically compressed at one point. The tubing must have at least two sections with two different stiffnesses. When a short segment of the tube is squeezed asymmetrically at certain frequencies, net flow of fluid around the loop can occur without valves.
Partial differential equations for the pressures, volumes, and flows define a simple one-dimensional model of such a pump, based upon elementary physical principles. Numerical computations on a personal computer can predict measured net flows.
Net flow varies with the frequency and waveform of compression used to excite the pump, as well as with the site of compression and the stiffness and viscosity of the tubing. Net flows on the order of 1 ml/sec are obtained in a water-filled loop including 46 cm of stiffer plastic (Tygon) laboratory tubing and 70 cm of softer latex rubber tubing.
The heretofore mysterious phenomenon of valveless pumping can be described in terms of classical Newtonian physics, in which viscous damping in the walls of the pump is included. Studying valveless pumps in the laboratory and modeling their behavior numerically provides a low-cost, engaging, and instructive exercise for research and teaching in biomedical engineering.
无阀泵在软黏弹性管的闭环内产生单向净液流，该闭环在一点处被周期性压缩。该管必须至少有两段具有两种不同的硬度。当管的短段以特定频率非对称地被挤压时，无需阀门即可在环路周围产生净液流。
基于基本物理原理，通过压力、体积和流量的偏微分方程来定义这种泵的简单一维模型。在个人计算机上进行数值计算可以预测测量得到的净流量。
净流量随用于激励泵的压缩频率和波形、压缩部位以及管的硬度和粘度而变化。在充满水的环路中，使用 46 厘米较硬的塑料（Tygon）实验室管和 70 厘米较软的乳胶橡胶管，可获得约 1 毫升/秒的净流量。
无阀泵送的神秘现象可以用经典牛顿物理学来描述，其中包括泵壁的粘性阻尼。在实验室中研究无阀泵并对其行为进行数值建模，为生物医学工程的研究和教学提供了一种低成本、引人入胜且富有教育意义的实践。
