This paper introduces the clarifying influence of the intertube spacing

the tube arrangement

the heat flux and the working fluid on boiling heat tra(?)sfer of smooth tube bundles. The tube bundles include the arrangements of twin tubes

triple tubes

seven tubes and thirteen tubes. The relative intertube spacing of the tube bundles is from 0. 9 to 3. 3. Experimental results show that the tube position and intertube spacting have no effect on boiling curves for the region of fully-devoloped boiling. And they considerably affect the heat transfer coefficient for the transition region between natural convection and nucleate boiling. In general

the heat transfer coefficient in the transition region for the upper tubes can be enhanced by 0. 5 to 1. 5 times.