摘要
交通流的物理本质是能量驱动的物质位移。为挖掘交通流和能量的关系,基于交通流功率分布模型探索建立了流量、速度、密度和能量四要素图谱。其中,能量(kJ·km^(-1)·h^(-1))在数学上描述为能耗因子(kJ·km^(-1)·veh^(-1))和交通流量(veh·h^(-1))的乘积。首先,基于均衡态交通流不同空间平均速度下的功率分布,建立随平均速度变化的能耗因子曲线;其次,基于4个经典交通流基本图模型(Greenshields、Greenberg、Underwood和Van Aerde)建立速度与流量关系;最后,结合流量和能耗因子得到流量-速度-密度-能量图谱。当能量转换效率为100%时:在速度-能量方面,流量对能量的变化起到主导作用,因此,随着速度上升能量呈现先上升后下降趋势;在密度-能量方面,随着密度上升能量同样先上升后下降,但由于密度和速度呈负相关,其变化原理与速度-能量相反;在流量-能量方面,同一流量可对应低速/高速下的拥堵/非拥堵状态,能耗因子随着流量上升呈现2种状态,能耗因子上升或能耗因子下降,但下降速率低于流量上升速率。该研究是面向能量网络制定精细化政策和优化能源网络设施设计的先行工作。
The physical essence of traffic flow is the energy-driven displacement of matter. To explore the relationship between traffic flow and energy, this study developed a four-factor diagram that included flow, speed, density, and energy based on the power distribution. In this context, the energy/(kJ·km~(^(-1))·h~(^(-1))) was mathematically described as the product of the energy factor/(kJ·km~(^(-1))·veh~(^(-1))) and the flow/(veh·h~(^(-1))). First, the energy factor curve varying with the average speed was established based on the power distribution of the traffic flow at each spatial average speed under equilibrium conditions. Subsequently, the relationship between the speed and the flow was obtained based on four classical traffic flow fundamental diagram models: Greenshields, Greenberg, Underwood, and Van Aerde. Finally, a flow-speed-density-energy diagram was established by combining the flow and energy factors. When the energy conversion efficiency was 100%, the following results were obtained. For speed-energy, as the speed increases, the energy first increases and then decreases because the flow plays a dominant role in the energy changes. For density-energy, the energy exhibits a pattern similar to that of the speed-energy relationship as the density increases;however, the changing pattern is the opposite, as the density is negatively associated with speed. For flow-energy, the energy increases with the flow. A flow value corresponds to two energy values under congestion/non-congestion conditions. Accordingly, the energy factors have two states as the flow increases: The energy factor is increasing or the decreasing rate of the energy factor is lower than the increasing rate of the flow. This study represents a pioneering effort towards formulating refined policies for energy networks and optimizing the design of energy infrastructure.
作者
黄健畅
宋国华
HUANG Jian-chang;SONG Guo-hua(School of Traffic and Transportation,Beijing Jiaotong University,Beijing 100044,China;Key Laboratory of Transport Industry of Big Data Application Technologies for Comprehensive Transport Ministry of Transport,Beijing Jiaotong University,Beijing 100044,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2024年第4期84-97,共14页
China Journal of Highway and Transport
基金
国家重点研发计划项目(2018YFB1600701)
国家自然科学基金项目(71871015,71901018)。
关键词
交通工程
流速密能
图谱
功率分布
能量
交能融合
traffic engineering
flow-speed-density-energy
diagram
power distribution
energy
integration of transportation and energy
