Influence of High-Frequency Pulsations of Liquid on Heat and Mass Transfer in Wide Minichannel during Liquid Flow Boiling

In this work, the influence of high-frequency pulsations of the liquid flow rate on the heat and mass transfer enhancement during flow boiling in a rectangular minichannel is investigated experimentally. The authors obtained a flow regime with controlled high-frequency pulsations of the liquid flow rate in which high values of the critical heat flux can be achieved due to a short-term increase in the liquid flow rate. This makes it possible to “wash off” large dry spots, prevent occurrence of flow and drying zones, and inhibit vapor film formation, which would reduce the heat transfer in the system. A flow regime with high-frequency pulsations will enable thermal stabilization of element surfaces exposed to unstable thermal loads. Visualization with an IR camera showed that a temporary increase in the liquid superficial velocity “washes off” dry spots, delaying the onset of heat transfer crisis in the system. High-frequency pulsations (0.1–1 Hz) enable increase in the critical heat flux in the system by 25% at the same average liquid flow rates.