Flow direction control in branched microchannels by combining electrical and magnetic fields

Substantial research in recent times has been focused on the improvement of flow performance in microchannels. However, due to the space restriction and size concern, a fixed geometrical microchannel is not always possible to use for varying conditions. Thus, an external method is required to control the flow in a microchannel for enhancing the flow performance of it. This study aims to analyze the applicability of combined effects of electrical and magnetic fields to generate a Lorentz force on a conducting fluid passing through a branched microchannel to effectively divert or bias the flow toward a particular direction. This allows the branched or networked channel to control the requirements of coolant in different required zones. This phenomenon is explored in this study by examining the effects of Lorentz force in single and double T-shaped microchannels. The effects of electrical (0–30 kV) and magnetic (0–1000 T) field strengths as well as polarity along with the varying channel geometry are analyzed individually. The combined application of orthogonal electric and magnetic fields induces a Lorentz force, resulting in the deflection of fluid flow from the inlet to either of the two outlets within a single T-shaped microchannel. Nearly 100% flow diversion can be achieved by this method. In the case of a double T setup, flow biasing to four individual outlets is found to be possible. The electric and magnetic fields exhibit a coupled influence on the flow behavior, wherein variation of either field independently yields analogous effects on the system response, consistent with the vector nature of the Lorentz force. Modulation of either the electric or magnetic field enables precise control over the flow distribution across the individual outlets, facilitating application-specific flow rate adjustments. This shows the immense possibilities of using electrical and magnetic fields to control flow in a fluid network without the use of complex hydromechanical systems. These can include precise coolant supply for hotspot mitigation in electronics, microchannel heat exchangers, reagent control, actuation of MEMS devices, etc.