Experiment On The Influence Of The Inside-Wall Condition Of The Pipe On The Boiling Characteristics Of The Flowing Water

In the nuclear-power device, usually use water as the heat transfer media, in order to ensure security, high-pressure water must be a single-phase liquid circulation in the primary circuits, and in the secondary circuits, hope that the boiling heat transfer coefficient and the critical heat flux the higher the better, to achieve the objective of efficient heat transfer and guarantee safe operation of nuclear-power device.At present, much effort has been given to the research about boiling heat transfer and hydraulics in the pipe, and the correlations are based on limited sets of data collected for specific experimental conditions. But now in the thermal study about reflect nuclear reactor, most literature lack the introduce of surface condition in the report about the single-phase liquid in the primary circuits and two-phase flow in the secondary circuits, based on the above background, research is carried out to investigate the influence of the inside-wall condition of the pipe on the boiling characteristics of the flowing water.On the basis of previous studies, according to the experiment purpose, make up of an experimental device, working three groupΦ10×1.5 pipes which was used in the nuclear-power device with different roughness, in the condition of the import pressure form 0.35MPa to 0.55MPa,and the water flow from 80 kg /h～180 kg /h , The major content is listed below:1,In order to observe the wall temperature changes, we try to use the infrared imaging system for non-contact temperature measurement.2,Research on the sub-cooling boiling heat transfer in the pipe, get the relationship between Heat flux and the degree of overheating, in the different roughness and different press.3,Research on the sub-cooling boiling heat transfer in the pipe, in different pressure, the flow characteristics of pressure drop in the three groups with different roughness.4,Research the onset of nucleate boiling in the sub-cooling boiling heat transfer, by the software of infrared imaging system, get the onset of nucleate boiling images.5,According to the measured experimental data, analysis the relationship between the boiling heat transfer coefficient and the wall roughness.The innovation of the paper is use of the infrared imaging system for non-contact measure the pipe wall's temperature, and use the intermittent temperature measured by thermocouple to calibration the infrared imaging system, gets the continuous possession of the temperature distribution, And thus get the exact location of ONB;By the experiment,we find that the ONB of the pipe with larger roughness is earlier than the pipe with low roughness.