A modified wall boiling model considering sliding bubbles based on the RPI wall boiling model

•Sliding bubbles are considered in the modified model.•The applicability of the modified model in a narrow rectangular channel is tested.•Bubble sliding distant is studied.•The void fraction distribution of cross section is studied. The bubble sliding is an important phenomenon in subcooled boiling flow, which has a significant influence to heat transfer, while the RPI wall boiling model does not consider the influence of sliding bubbles directly. This paper proposes a modified wall boiling model considering the sliding bubbles, and the simulation results of the modified model are compared with the experimental data to verify the accuracy of the model. According to the results, the modified model is applicable for the mass flux from 648.4 to 1630 kg/(m2•s), with the heat flux range of 227 to 306 kW/m2, the inlet subcooled temperature range of 30 to 50 K and the pressure range of 0.2 to 0.4 MPa. In addition, bubble departure diameter, bubble lift-off diameter, bubble sliding distance and the distribution of heat flux are discussed in this paper.