Experimental investigation of forced flow boiling of nitrogen in a horizontal corrugated stainless steel tube

• Forced flow boiling of LN2 was investigated in a corrugated stainless steel tube.
• The influence of the heat flux, mass flow flux and vapor quality on the two-phase heat transfer characteristics was analyzed.
• Circumferential averages of the HTCs were compared with four general flow boiling heat transfer correlations.
• The two-phase heat transfer is enhanced due to the area augmentation in the present corrugated tube.

Experimental investigation is performed on the heat transfer characteristics of forced flow boiling of saturated liquid nitrogen (LN2) in a horizontal corrugated stainless steel tube with a 17.6 mm maximum inner diameter. The local heat transfer coefficients (HTCs) are measured at two mass flow rates with a wide range of wall heat fluxes. The effects of the heat flux, mass flow flux and vapor quality on the two-phase heat transfer characteristics are discussed. The results reveal that the local HTCs increase with the heat flux and mass flow flux. The measured local HTCs present a strong dependence on the heat flux. The circumferential averages of the HTCs for the present corrugated tube are compared with the empirical correlations proposed for the smooth tubes, and the results show that the heat transfer is enhanced due to the area augmentation.