＂U＂ and ＂U＋I＂ type ventilation experiments were performed on a three-dimensional fully mechanized caving face simulation experimental platform. The distribution laws of the pressure field and gas field in the min...＂U＂ and ＂U＋I＂ type ventilation experiments were performed on a three-dimensional fully mechanized caving face simulation experimental platform. The distribution laws of the pressure field and gas field in the mine goal were obtained. Results show that the flow field in the goaf is generally asymmetric; the location of the gas accumulation area changes with ventilation parameters and can be used as an evaluation indicator to study the air leakage extent in the goal. Hence, drainage pipes buried in the goaf to intensively extract gas can be designed in such gas areas, which can give considerations in both improving gas drainage efficiency and reducing air leakage. By comparing the gas extraction effect of model experiments with that of on-site underground practices, the basic laws are commonly consistent according to comparative analysis. Thus the experimental results can be used to guide the application of underground gas prevent!o_n_and.control..展开更多
The characteristics of the confined bubble and elongated bubble in subcooled flow boiling in a single horizontal rectangular microchannel with hydraulic diameter Dh=1mm are studied experimentally. The channel with 1 &...The characteristics of the confined bubble and elongated bubble in subcooled flow boiling in a single horizontal rectangular microchannel with hydraulic diameter Dh=1mm are studied experimentally. The channel with 1 ×1mm cross section is fabricated in a thin copper plate whose confinement number is Co=2.8 and the degassed deionized water is used as the working fluid. Visualization on the confined and elongated bubbles inside the microchannel is carded out by employing a high-speed CCD camera with a rnicrolens. The recorded images are carefully analyzed to illustrate the behaviors of the confinement and elongation processes of the bubble. The boiling number is used as an adjustable parameter to regulate the operating conditions which is eventually found to take a vital role in the bubble elongation process. Two formation patterns of the confined and elongated bubble are identified and the interactions between the neighboring confined and elongated bubbles are elucidated.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51174198 and 51304203)Supported by State Key Laboratory of Coal Resources and Safe Mining (No. SKLCRSM11X01)
文摘＂U＂ and ＂U＋I＂ type ventilation experiments were performed on a three-dimensional fully mechanized caving face simulation experimental platform. The distribution laws of the pressure field and gas field in the mine goal were obtained. Results show that the flow field in the goaf is generally asymmetric; the location of the gas accumulation area changes with ventilation parameters and can be used as an evaluation indicator to study the air leakage extent in the goal. Hence, drainage pipes buried in the goaf to intensively extract gas can be designed in such gas areas, which can give considerations in both improving gas drainage efficiency and reducing air leakage. By comparing the gas extraction effect of model experiments with that of on-site underground practices, the basic laws are commonly consistent according to comparative analysis. Thus the experimental results can be used to guide the application of underground gas prevent!o_n_and.control..
基金supported by National Natural Science Foundation of China (No. 51176008)the Fundamental Research Funds for the Central Universities (No.2011YJS267)Jiangsu Key Laboratory of Process Enhancement & New Energy Equipment Technology(Nanjing University of Technology)
文摘The characteristics of the confined bubble and elongated bubble in subcooled flow boiling in a single horizontal rectangular microchannel with hydraulic diameter Dh=1mm are studied experimentally. The channel with 1 ×1mm cross section is fabricated in a thin copper plate whose confinement number is Co=2.8 and the degassed deionized water is used as the working fluid. Visualization on the confined and elongated bubbles inside the microchannel is carded out by employing a high-speed CCD camera with a rnicrolens. The recorded images are carefully analyzed to illustrate the behaviors of the confinement and elongation processes of the bubble. The boiling number is used as an adjustable parameter to regulate the operating conditions which is eventually found to take a vital role in the bubble elongation process. Two formation patterns of the confined and elongated bubble are identified and the interactions between the neighboring confined and elongated bubbles are elucidated.
