Experimental Investigation On Pool Boiling Heat Transfer Of Methane And Its Hydrocarbon Mixtures

The nucleate pool boiling heat transfer data of liquefied nature gas (LNG) is important for design and optimization of LNG transportation, storage and gasification equipments. The heat transfer characteristics of pool boiling of methane and its hydrocarbon mixtures were investigated theoretically and experimentally in this dissertation.First of all, after careful references review, a new apparatus for LNG pool boiling heat transfer measurement was designed and established, in which high accurate temperature and pressure transducers were used to obtain such important parameters. With this apparatus, the pool boiling heat transfer behaviors of methane and its natural gas mixtures were measured systemically, and some analysis were also made on the measured results, the details are listed as follows:Systematic measurements on pool-boiling heat transfer of methane and its hydrocarbon mixtures were performed. In detail, these substances such as pure methane, three binary mixtures of methane + ethane, methane + propane, methane + isobutane and a multi-component mixture were measured extensively at 0.13MPa (approximately 115 K) in this paper. The pool boiling data of pure methane and its mixtures were measured at different heat flux. The influence on boiling behavior of these substances with different components and composition were also obtained. The data shows the heat transfer characteristic of liquid changes with the change of the components.The heat transfer characteristic of methane and its mixtures were analyzed deeply in this paper. Compared with pure methane's boiling data, the heat transfer coefficients of mixtures decrease with the decrease of the methane composition in the mixture. This is due to the change of the mixture thermal properties and the mass transfer resistance near the boiling surface. The existed heat transfer correlations were summarized and some of the well known correlations were compared with the present experimental data. The result shows that Nishikawa's correlation agrees well with the methane experimental data. However, there are no correlations agreeing well with the mixture data. The status of the surface was analyzed with the experimental data. The bubble's diameter of department and the bubble's departure frequency were calculated for each condition in this experiment. The active nucleate sites density of nucleate pool boiling was calculated as well. Such analyses are helpful in understanding the LNG pool boiling in low temperature range. In a word, experiments of nucleate pool boiling heat transfer characteristics of liquid methane and its hydrocarbon mixtures were carried and the experimental data are analyzed in this paper.