Experiments were performed to examine the influence of thin wire heater orientation (phi = 0 degrees (horizontal), 22 degrees, 33 degrees, 44 degrees, 49.5 degrees, 74 degrees and 90 degrees (vertical)) on nucleate boiling in subcooled dodecane. Variations of both heat flux (q '') and temperature difference (Delta T) along with phi change were analyzed. The number, velocity, and size of bubbles (whose size were larger than the wire diameter) were recorded, and their influence on critical heat flux (CHF) at different orientation angles were discussed. As phi increased, CHF variations decreased slowly at first and then quickly. The decrease in CHF was accompanied by decrease of bubble number and size, but increase of bubble speed along the wire. A critical angle of phi = 22 degrees shows the highest heat transfer coefficient (HTC). (C) 2019 Elsevier Ltd. All rights reserved.