Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

•The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel.•Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model.•The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment.•The result shows water-cooling channel is good for the joule heat transfer and taken away.