CONSECUTIVE-PHOTO METHOD TO MEASURE VAPOR VOLUME FLOW-RATE DURING BOILING FROM A WIRE IMMERSED IN SATURATED LIQUID

A photographic measurement technique is developed to quantify the vapo r volume flow rate departing from a wire during boiling, The vapor flo w rate is determined by measuring the volume of bubbles after departur e from the boiling surface in consecutive frames of high-speed video. The measurement technique is more accurate and easier to implement tha n a previously developed photographic/laser Doppler anemometry (LDA) m ethod. Use of the high-speed camera in place of a standard video camer a eliminates the requirement for LDA-acquired bubble velocity measurem ents. The consecutive-photo method requires relatively few video image s to be analyzed to obtain steady-state vapor volume flow rates. The v olumetric flow rate data ai-e used to calculate the latent heat transf er and, indirectly, sensible hear transfer which comprise the nucleate boiling heat flux. The measurement technique is applied to a 75-mu m diameter platinum wire immersed in saturated FC-72.