BUBBLE COALESCENCE AND MOVING CONTACT LINE EVAPORATION DURING FLOW BOILING IN A SINGLE MINICHANNEL

Cooling systems incorporating flow boiling in mini- and microchannels achieve very high thermal performance. In this study a comprehensive measurement technique is used for the investigation of flow boiling in a single rectangular minichannel. This technique allows the measurement of local surface heat flux and temperature with a very high spatial and temporal resolution in combination with a synchronized flow regime observation [1]. This way, an insight into the basic phenomena is possible and will contribute to the fundamental understanding of the process. The experimental results show different phenomena such as an alternating area of high heat transfer between bubble front and end for elongated bubbles and the coalescence of bubbles in the flow. These observed phenomenon are comparable to experimental and numerical results of pool boiling.