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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EXPERIMENTAL INVESTIGATION OF FLOW BOILING HEAT TRANSFER BOUNDARY OF NITROGEN IN 1.2 MM VERTICAL MINI-CHANNEL

Get access (open in a dialog) DOI: 10.1615/IHTC16.mpf.024048
pages 6861-6868

摘要

The flow boiling heat transfer boundary of nitrogen in single vertical 1.2mm mini-channel under inlet pressure of 0.4-1.5 MPa were experimentally investigated. The pressure drop and the wall temperature profiles were synchronously measured. The liquid mass flux ranged from 1000 to 2000 kg/m2s and the heat flux was in a range of 0-98 kW/m2. Due to the nitrogen specific property, it is fairly commonly seen that the subcooled flow boiling exists before the saturated flow boiling occurs. Three types of the heat transfer regimes were identified based on the boiling curve and the boundary of heat transfer regimes were given, i.e. the single-phase and subcooled flow boiling region, the saturated flow boiling region and the dry-out region. The CHF easily occurs in nitrogen flow boiling. Higher mass flux has a better capacity to avoid the dry-out region. The critical exit vapor quality is 0.15, which corresponds to the transition from the bubbly/slug flow to the annular flow. The mass flux has little effect on the critical exit vapor quality.