An Improved Flow Chamber System Which Can Reproduce Physiologic Arterial Flow Conditions And Numerical Analysis Of It

Many devices have been used to study the response of mammalian cells to mechanical loads, such as modified cone-plate viscometers, bioreactors, and flow chambers, among which the parallel plate flow chamber (PPFC) is the most commonly used. The fundamental principle is as follows. First, cells are adhered to the bottom of flow chamber, the shear stress which is caused by the near wall flow of suspension in the flow chamber acts on cells, second, the properties of cells are studied under different shear stress. Most studies using PPFC are carried under steady flow conditions, only a limited number of in vitro studies have taken account for the influence of pulsatile flow. However, current methods to induce pulsatile flow in a flow chamber system are limited by the creation of non-physiologic flow and pressure waveforms. It is believed that the arterial flow and pressure waveforms are important factors in arterial vessel remodeling. Therefore, much more useful information may be achieved if a flow, which is similar to the in vivo arterial pulsatile flow, is applied to cultured cells in a PPFC.In this paper, a novel PPFC system was developed by our laboratory, which can supply pulsatile flow field for cultured vascular cells. The PPFC system is composed of three units with three elements, and driven by a computer-controlled linear pump,based on a numerical simulation by using a lumped-parameter model. The PPFC system can generate well characterized arterial pressure and flow waveforms similar to mammalian physiology and fully developed laminar flow properties. From the unanimous of the experiment and simulation results, we can draw a conclusion that apply the flow chamber to lumped model is reliable.Select the key points of a period, under the given inlet and outlet pressure data in the experiments. We can simulate the velocity, pressure and shear stress in the flow chamber by using the dynamics software Fluent. From the calculation result, we find that the shear stress is equal in center field. By analyzing the experiment and simulation results, we find there is almost no difference between them. The calculated numerical results demonstrate that, when the pulsatile flow with small Womersley number, the quasi-steady formula is highly precise for various commonly used flow parameters and geometrical dimensions of the PPFC, which provides theoretical basis for the calculation of the shear stress in the PPFC under pulsatile flow condition.We obtain the pressure and flow similar to mammalian physiology by using the lumped model, and simulate the flow in flow chamber by using Fluent, especially the shear stress in the center field. Combining with the numerical analysis of the flow filed in the PPFC, this parallel plate physiological pulsatile flow chamber system can be used to study vascular cellular mechanical behaviors.