Effects of wall compliance on pulsatile flow attenuation in microchannels.

The attenuation of pulsatile flow through highly compliant microchannels has been investigated. The expansion of a compliant microchannel subjected to pulsatile flow is able to store fluid temporarily and thereby reduce the peak-to-peak magnitude of flow fluctuation. In a highly compliant microchannel, the microchannel expansion reduces its hydraulic resistance and its associated pressure drop. For a similar inlet pressure condition, the pressure drop along the length of a more compliant microchannel is lower than a rigid microchannel. Therefore, greater net pressure is available to deform the microchannel wall. So the hypothesis of this study is the coupled relationship between higher pressure and greater wall compliance which will achieve more effective flow stabilization, because both contribute synergistically to greater volumetric expansion. To investigate this hypothesis, a soft elastomer, polydimethylsiloxane was used to compare plain microchannels and microchannels with a series of laterally deformable membranes, which vary in terms of wall compliance. In a 6 Hz pulsatile flow experiment, a membrane microchannel is able to achieve a better pulsatile flow attenuation ratio of 16 when compared to a plain microchannel pulsatile flow attenuation ratio of 10. The hypothesis was also investigated with a 2-D fluid-structure interaction numerical model and the prediction is in agreement with experimental results. The results indicate that higher compliance microchannels have better pulsatile flow attenuation abilities