PSHE（Personal,Social,Health and Economic）课程兴起于英国,是一门培养学生有关自信、健康和独立生活的知识、技能和其他能力,能够养成健康生活方式和形成良好的人际关系的,并且能够处理生活中道德、文化等问题的课程[1]。该课程包...PSHE（Personal,Social,Health and Economic）课程兴起于英国,是一门培养学生有关自信、健康和独立生活的知识、技能和其他能力,能够养成健康生活方式和形成良好的人际关系的,并且能够处理生活中道德、文化等问题的课程[1]。该课程包括个人教育、社会教育、健康教育和理财教育四个方面的内容。展开更多
英国中学普遍开设名为PSHE(Personal,Social and Health Education,即个人、社会与健康教育)的课程。学校的教学大纲规定,该门课程的教学目的是倡导健康的生活方式,使学生在生活技能、表达能力、学习新知识、思考能力、与人相处以及道...英国中学普遍开设名为PSHE(Personal,Social and Health Education,即个人、社会与健康教育)的课程。学校的教学大纲规定,该门课程的教学目的是倡导健康的生活方式,使学生在生活技能、表达能力、学习新知识、思考能力、与人相处以及道德修养等方面都得到提高。根据英国《国家课程》的规定。展开更多
Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop cha...Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop channels, besides a third mixed configuration as to achieve in-between results regarding hydraulic performance. Friction factor correlations were provided with the channel Reynolds number ranging from 1175 to 8325. Two-dimensional (2D) mean velocity field was obtained by Particle Tracking Velocimetry (PTV) with Reynolds number equal to 3450. To the best of our knowledge, this is the first experimental study that quantified the complete 2D velocity field of a typical PHE channel. This value allowed comparison with literature results of Plate and Shell Heat Exchanger (PSHE) channels with the same Reynolds number. PSHE mean velocity field is highly heterogeneous as compared to the one obtained for PHE channels. Peak velocity magnitude in the PSHE center is 50% higher than its bulk velocity, whereas this value is only 15% higher in the PHE center. Pressure drop in PHE mixed channels cannot be approximated by averaging chevron angles: furrow flow prevailed in the specified conditions. The axial velocity is asymmetric regarding the vertical plane. Smooth streamlines prevail in the channel inlet. Recirculation zones at the channel exit affect pipe flow in the manifold outlet with swirling flow structures. The necessary length to obtain fully developed pipe flow at the channel outlet was estimated. Significant velocity components occur in the distribution areas and can limit the heat exchanger performance. The results reported herein are essential to understand how the PHE channel geometry affects the velocity field and, therefore, local heat transfer and dissipation processes.展开更多
文摘PSHE（Personal,Social,Health and Economic）课程兴起于英国,是一门培养学生有关自信、健康和独立生活的知识、技能和其他能力,能够养成健康生活方式和形成良好的人际关系的,并且能够处理生活中道德、文化等问题的课程[1]。该课程包括个人教育、社会教育、健康教育和理财教育四个方面的内容。
文摘英国中学普遍开设名为PSHE(Personal,Social and Health Education,即个人、社会与健康教育)的课程。学校的教学大纲规定,该门课程的教学目的是倡导健康的生活方式,使学生在生活技能、表达能力、学习新知识、思考能力、与人相处以及道德修养等方面都得到提高。根据英国《国家课程》的规定。
文摘Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop channels, besides a third mixed configuration as to achieve in-between results regarding hydraulic performance. Friction factor correlations were provided with the channel Reynolds number ranging from 1175 to 8325. Two-dimensional (2D) mean velocity field was obtained by Particle Tracking Velocimetry (PTV) with Reynolds number equal to 3450. To the best of our knowledge, this is the first experimental study that quantified the complete 2D velocity field of a typical PHE channel. This value allowed comparison with literature results of Plate and Shell Heat Exchanger (PSHE) channels with the same Reynolds number. PSHE mean velocity field is highly heterogeneous as compared to the one obtained for PHE channels. Peak velocity magnitude in the PSHE center is 50% higher than its bulk velocity, whereas this value is only 15% higher in the PHE center. Pressure drop in PHE mixed channels cannot be approximated by averaging chevron angles: furrow flow prevailed in the specified conditions. The axial velocity is asymmetric regarding the vertical plane. Smooth streamlines prevail in the channel inlet. Recirculation zones at the channel exit affect pipe flow in the manifold outlet with swirling flow structures. The necessary length to obtain fully developed pipe flow at the channel outlet was estimated. Significant velocity components occur in the distribution areas and can limit the heat exchanger performance. The results reported herein are essential to understand how the PHE channel geometry affects the velocity field and, therefore, local heat transfer and dissipation processes.
