Abstract: As only few reports on flow boiling heat transfer in non-circular minichannels are published, flow boiling heat transfer characteristics of R113 in square- and triangular-section minichannels are experimentally investigated. The experiments are performed with the inlet vapor quality ranging from super-cooling to 1.0, mass velocity from 400 to 3 300 kg/(m2?s), and heat flux from 20 to 150 kW/m2. And the experimental data are compared and analyzed with those in circular minichannel hav-ing close hydrodynamics diameter. The results show that the local wall temperature depends heavily on the mass velocity in non-circular channel flow boiling, which is affected by the heat flux and the mechanism of flow boiling heat transfer. Both mass velocity and heat flux could effect on the mean heat transfer coefficient of saturated flow boiling in non-circular minichan-nels. According to the experimental data in both non-circular and circular minichannel with nearly equal hydrodynamic di-ameter, the non-circular minichannels appear to have remark-able heat transfer enhancement effect.

Key words: Flow boiling, Heat transfer enhancement, inichannel, Non-circular channels