【作者】 张志勤；

【导师】 朱颖心；

【作者基本信息】 清华大学 ， 土木工程， 2004， 硕士

【摘要】 随着中国城市化进程的不断加速,住宅小区成为中国城市人口的主要居住形式,创建健康、舒适、环保的住宅小区热环境越来越受到人们的重视。在小区环境设计中,喷泉已经成为一个重要的亮点。然而,长期以来喷泉对小区热环境的影响一直缺乏系统的研究。针对以上不足,开展了以下几个方面的研究。首先,由于室外热环境的复杂性,本课题针对室外测试的特点,提出了室外热环境参数测量的方法,并且对喷泉周围热环境参数进行了系统、详细的测量。通过对结果数据的分析,得到了室外喷泉周围热环境参数分布的特点。然后,从单个水珠出发,建立了水珠与空气的热质交换的计算公式,同时采用拉格朗日方法,在PSI-CELL模型的基础上,给出空气与水珠热质耦合计算的数学模型,并且将模型嵌入PHOENICS中,对喷淋室冷却加湿过程进行模拟,验证了该模型的准确性和可靠性。在对直管压力射流破碎过程进行详细分析的基础上,模拟了喷泉周围热环境,并将模拟结果与实验结果进行了对比,验证了喷泉模型的准确性,同时指出了风向和风速对结果验证影响的重要性。最后,根据小区环境联合模拟程序的特点,给出了喷泉嵌入联合模拟程序的方法,并且通过数值实验对比证明了方法的准确性,其计算精度完全能够满足工程应用要求。同时对影响喷泉周围热环境的各参数进行了数值实验,提出了优化喷泉设计的指导意见。包括:喷泉应当设在小区内人员活动密集、热舒适性差、空气流动通畅的广场、街道中间等地;尽可能降低喷水温度,或者通过改善喷嘴性能降低水珠粒径;射流高度控制在3.5 m;不建议通过增压、提过高流速和喷水量等方法来改善热环境;通过采取并排、增大间距等方式减小风速降幅;根据喷泉周围活动区域大小灵活选择喷嘴布置;具体的设计参数应该根据实际情况进行模拟优化。本论文为在小区环境联合程序中数值模拟喷泉周围热环境提出了解决方案,并且使得优化喷泉周围热环境设计成为可能。更多还原

【Abstract】 With the acceleration of Chinese urbanism pace, residential clusters have become the popular dwellings for Chinese resident. It has been gradually emphasized by most people to create healthy, comfortable, and green thermal environment in a residential cluster. In planning, fountains have been the focus of the public area. However, the systematic research of the thermal environment around fountains is lack. Aiming at this absence, some researches have been carried out.First of all, because of the complexity of outdoor thermal environment, some measurement means are advanced to decrease the error. Besides, a systematic and detailed experiment is put up. Based on the analysis of the experimental data, the distribution characteristics of the thermal parameter around the fountain are presented. Then, the calculation formulas of the heat and mass transfer between a droplet and the surrounding air are derived from the analysis of a single droplet. Lagrangian Schemes are adopted and the coupling calculation model between the air and droplets is advanced on the base of PSI-CELL model. The validity and reliability of the model is verified by simulating the air-handling process in a spray chamber. Moreover, the breakup process of a straight pressure atomizer is analyzed and the thermal environment around a fountain is simulated. The result is compared with the experimental data and the validity of the model is verified. At the same time it is pointed out that the wind velocity and direction have great influence on the comparison.At last, the coupled calculation method including fountains is advanced according to the characteristic of the simulation flow and it is verified by numerical experiment. At the same time the factors that affect the thermal environment around a fountain are analyzed by numerical experiment and some guidelines are presented to optimize the design of a fountain. These guidelines include: Fountain should be <WP=5>planned in a square or in the middle of a main street with large density occupant, bad thermal comfort and good ventilation; Decrease the water temperature as lower as possible; Reduce the SMD of the droplets by reform the atomizer; Controlling the jet height about 3.5 m; It is not suggested to improve the thermal comfort by raising pressure, flow velocity or flux; Decrease the change of the air velocity by larging the gap of the atomizer or arranging the atomizer in-line; Planning the atomizer according the public; All the design parameter should be optimized by simulation according to the fact.The conclusion of this thesis brings a scheme for the fountain thermal environment simulation in couple calculation of a residential cluster environment and makes it possible to optimize the design of a fountain.更多还原