EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER CHARACTERISTICS OF LIQUID NITROGEN FLOW BOILING IN A MINI-CHANNEL
Flow boiling of cryogenic fluids in mini-channels is becoming an increasingly important topic for its high heat dissipation capability. In the present study, the effects of mass flux, heat flux and vapour quality on liquid nitrogen flow boiling in a mini-channel are experimentally investigated. The test section, which is positioned vertically in the vacuum flask, is a stainless steel circular tube with an inner diameter of 1.2 mm and a length of 300 mm. The experiments are performed at the mass fluxes of 1260 kg/m2s, 1800 kg/m2s and 2050 kg/m2s. The effective heat flux range is 8.934 kW/m2-94.391 kW/m2. Ten thermocouples are soldered on the outer surface of the mini-channel to monitor the local surface temperatures. Local heat transfer coefficients are calculated and the impacts of mass flux, heat flux and local vapour quality on heat transfer
characteristics are discussed.