Waves in Liquid Film Regimes of Adiabatic Two-Phase Flow in a Slit Microchannel

Two-phase and two-component flows in microchannels being very promising for applications in areas such as microfluidics, microelectronic cooling, and heat exchange systems, there is a need to study characteristics of these flows and new effects associated with microchannel flows. This work presents an experimental and theoretical study of waves in stratified and annular flow regimes for a flat slit microchannel 104 mu mhigh and 10mmwide, with isopropanol used as a working liquid and nitrogen used as a gas. The lengths of waves appearing on the film on the lower wall of the microchannel were measured experimentally. Quantitative dependences of the wavelengths on the liquid and gas flow rates were obtained. A numerical calculation was performed using analysis of linear stability. The experimental data on the wavelengths were compared with the results of numerical calculations for wavelengths ofmaximum growth. Dependences of the averaged distances of transitions from 2D to 3D waves on the Reynolds numbers of the liquid and gas were obtained experimentally. Dependences of the maximum spatial rate of perturbation growth on the Reynolds numbers of the liquid and gas were found numerically and experimentally.