Investigation of water microchannel boiling flow regimes using electrical sensing elements along a single microchannel

Abstract

In this work, we present a method that allows for the detection of the local flow regime in a metallic microchannel using on-channel electrical sensing elements. The development of the flow regime is analyzed along a straight channel (length: 63.5 mm, width: 1.5 mm, height: 0.5 mm) using four transparent electrodes fabricated on a glass lid. A constant heat flux boundary condition at the channel walls is applied to deionized water flow. Measurements are validated by recorded videos at the same locations as the sensing elements. The topology of the probability densities of impedimetric measurements shows a clear connection with visually observed flow regimes, including bubbly, slug, wavy/churn and annular flow. The method and test facilities show promising potential for further investigations into how variable channel geometries and local process parameters influence microchannel boiling.