社区尺度热环境快速准确预测与区域建筑能耗模拟耦合的仿真方法研究

With the accelerated urbanization, the urban thermal environment has attracted significant attentions. Through improving local urban neighborhood thermal environment that can reduce building energy consumption and improve the quality of human living environment, has been one of the important research field of urban planning and building energy conservation. Due to the requirement of high computational resource for macro-scale and medium scale urban thermal environment, the current numerical simulations of urban thermal environment were limited to micro-scale of the city center or suburban. This research investigates an improved zero-equation turbulence model that can rapidly and reliably predict thermal environment in urban neighborhood, by conducting scaled wind tunnel experiment and full-scale field measurement. Because the standard wall function can over-estimate the heat transfer in the adjacent building wall, so this project provides an adaptive-temperature wall function, and solves the problem of near-wall treatment and the requirement of finer mesh, in order to figure out the tradeoff between the purpose of accuracy of simulation results and limitation of current computational resources. These above zero-equation turbulence model and adaptive temperature wall function are integrated into an open-source Computational Fluid Dynamics (CFD) software, which was combined with an open-source Building Energy Simulation (BES) program. Finally, a new co-simulation technology with airflow program and energy consumption program is achieved. The co-simulation technology can rapidly and accurately transfer the weather data and building surface temperature between CFD and BES, and can qualify the effect of local urban neighborhood thermal environment on district building energy consumption. In the end, this project can provide sufficient theoretical foundation for the urban energy planning and building energy conservation through the rapid and reliable airflow and energy coupled simulation platform.

随着城市化进程加快，城市热环境日益受到重视，通过改善区域热环境来降低建筑能耗和提高人居环境质量已成为城市能源规划和建筑节能领域重要的研究方向之一。由于中大尺度环境仿真计算机资源需求大，目前城市热环境的预测仍仅局限于微尺度范围。本课题采用缩尺风洞实验和全尺度现场测试，研究一种快速有效地预测城市社区尺度热环境的零方程湍流模型；针对标准壁面方程过高预测近壁区对流换热的问题，研究一种可调节式的温度壁面函数，解决近壁区低雷诺数网格精细要求问题，实现兼顾计算结果准确和计算机资源有限的折衷方式。将上述湍流模型和温度壁面函数集成进免费开源的计算流体动力学仿真软件，与免费开源的建筑能耗模拟仿真软件相整合，构建气流与能耗耦合模拟的新型仿真技术，快速而准确地实现两者间气象温度、风速和壁面温度等参数的传递，定量探讨城市社区尺度下的局地热环境对区域建筑能耗的影响，最终为今后城市能源规划与建筑节能提供坚实的理论基础。

城市热环境研究及其对建筑能耗的影响日益受到重视，现有的建筑能耗预测大多局限于单栋建筑，且大多工具无法比较快速地预测建筑热环境和准确评估区域热环境对建筑能耗的影响。针对上述问题，研究主要内容为：研究通过缩尺实验优化改进应用于室外热环境的零方程湍流模型，集成在开源OpenFOAM软件中，通过实验数据，与SKE和LES湍流方程对比，验证其准确性并分析其应用的优劣；研究热环境空气温度、风速和建筑壁面温度等参数的数据传递方式，构建快速准确的气流和能耗耦合仿真平台；利用逐4h法和插值法预测最热月室外温度，修正不同风向和风速，分析容积率和绿化对小区热环境及建筑冷热负荷、空气渗透能耗和建筑总能耗的影响；研究测试美国马里兰大学校园局地热环境，验证数值仿真模型的准确性，实现了快速且定量分析单向耦合模式下区域建筑尺度下不同热环境参数对建筑能耗的影响。主要研究结果表明：（1）针对单栋建筑、规则街区和建筑群模型，优化的零方程湍流模型与SKE和LES模型相比，能快速（1:5:30）且相对准确地预测室外气流环境；（2）利用耦合仿真平台，分析得到济南某小区规划建筑容积率每增加10%，最大冷负荷指标约增加4%，制冷耗电量约增加5%；绿化对目标建筑的潜热负荷影响较大，与无绿化工况相比，潜热负荷增加13.8%；（3）以马里兰大学校园建筑为例，与独栋建筑相比，区域尺度建筑典型日平均空气温度（白天）增加约2.1℃，日平均风速（白天）减少约0.5m/s，日空调能耗峰值增加约19.7%，全天空调能耗增加约6.9%；模拟研究发现区域环境下建筑年供冷量和年供热量分别增加2.67%和减少2.18%。项目研究成果探讨城市区域尺度下的局地热环境对建筑能耗的影响，最终为今后城市能源规划与建筑节能提供坚实的理论基础。