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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

EFFECT OF THE NON-CONDENSABLE GAS CONTENTS ON HEAT TRANSFER CHARACTERISTICS OF TWO-PHASE CLOSED THERMOSYPHON

Get access (open in a dialog) DOI: 10.1615/IHTC16.her.023199
pages 4559-4566

Abstract

The thermosyphon is made of copper and the inner diameter is 25 mm. It consists of three sections; evaporator, adiabatic and condenser, which are 300, 300, and 325 mm long, respectively. Deionized water is used as a working fluid. Eight cartridge heaters are inserted into the evaporator section to supply the uniform heating and the condenser section is surrounded by the water jacket. Local wall temperatures at both top and bottom surfaces are measured by T-type thermocouples at nine different points of the thermosyphon. The internal temperatures at the same points are also measured by inserting the thermocouples through the pipe. The inlet and outlet temperatures of the coolant at the condenser section are measured to calculate the heat rejection at the condenser. The contents of non-condensable gas are controlled into four cases − degassed, low, medium and high contents. The thermosyphon performance is measured at the heat flux ranging from 10 to 300 kW/m2 and inclination angles of 15°, 45° and 90°. The results show that the heat transfer coefficients in the evaporator section increase with heat flux at the inclination angle of 45° and 90°. However, boiling heat transfer coefficient at the inclination angle of 15° exhibits some degradation due to the partial dry-out. The Rohsenow correlation is used to normalize the heat transfer coefficients of the evaporator. The effect of non-condensable gas at the evaporator section is minimal. In contrast, the heat transfer coefficients at the condenser section show significant difference according to the amount of non-condensable gas.