Two-phase flow boiling frictional pressure drop of liquid nitrogen in horizontal circular mini-tubes: Experimental investigation and comparison with correlations

•The influence of heat flux on pressure is not obvious.•The influence of inlet pressure is weak at low pressure.•The frictional pressure drop of two-phase flow of LN2 is compared with four empirical models.•A numerical model to predict the frictional pressure drop of liquid nitrogen is developed.•The model considers the effects of both Reynolds number and Weber number.