An axisymmetric model of the controlled fluid flow damper

In recent years there has been a significant scientific interest in the development of structures based on microfluidics, because this direction has great potential for miniaturization of technical devices. An example is a capillary microgripper capable of holding plane microobjects due to surface tension forces. Microgripper operation requires uniform heat dissipation from the hot surface of the Peltier element, which creates a temperature below the dew point on the working surface of the microgrip. Early studies have shown that at low-frequency fluid flow pulsation, heat removal is uneven, which can disrupt stability in the manipulation of a microgripper that holds an object. For this reason, the study of the performance of a microgrip cooling system with intent to find the optimal mode in which the micropump will provide a constant coolant flow without low-frequency oscillations seems to be relevant. The paper proposes a mathematical model of the damper for smoothing the liquid flow pulsations generated by a micropump in the cooling system of a capillary microgripper. The ultra-small volumes of pumped fluid, the specifics of its behavior in microchannels, and the features of micropump operation require a special approach to model building. An axisymmetric model of a controlled fluid flow damper that adequately reflects both the smoothing of fluid flow pulsations and the regulation of the average flow rate is proposed. Three modes of damper operation are considered: as a stationary hydraulic resistance, in the modes of oscillating fluid flow and smoothing the oscillating flow. Based on the results of the computational experiments, an approximation of the fluid flow rate versus the amplitude of radial compression of the microtube is carried out. This made it possible to derive analytical formulas calculating the dependence of the fluid flow rate under stationary hydraulic resistance for the generation of an oscillated fluid flow. An analytical iterative algorithm for describing the damping of a fluid flow to smooth an oscillating flow is proposed. The algorithm does not require significant computing resources and can be used in a real-time fluid flow damper control system.