ISSN Online: 2377-424X
ISBN CD: 1-56700-226-9
ISBN Online: 1-56700-225-0
International Heat Transfer Conference 13
AN EXPERIMENTAL STUDY ON PRESSURE DROP AND HEAT TRANSFER PERFORMANCE OF SUB-COOLED AND SATURATED FLOW BOILING IN A MICRO-TUBE
Аннотация
This paper presents an experimental study on the pressure drop and the heat transfer performance of sub-cooled and saturated water boiling in a horizontal stainless steel micro-tube with an inside diameter of 0.399 mm and heated length of 80mm. The experiments have been conducted under the conditions of mass flux from 79.6 to 265.4 kg/m2s, inlet temperature from 30 to 60 °C, and heat flux from 5 to 25 W/cm2. It is observed that the outlet temperature and pressure drop fluctuated dramatically during sub-cooled flow boiling. Using the Infrared Radiometry, the flow boiling patterns are estimated from the thermographs. It is found that the flow boiling patterns of water in micro-tube are consisted of alternate changes of sub-cooled single flow, plug flow and annular flow with increasing of the heat flux, the fluid met the saturated boiling. Based on the experimental result, a new pressure drop correlation is derived with the mean absolute error less than 10.4%. The effects of mass flux, inlet temperature and vapor quality on the saturated boiling heat transfer performance are discussed.