纯电动公交车内气流分布特性及热舒适性研究

发布时间：2018-01-07 13:26

本文关键词：纯电动公交车内气流分布特性及热舒适性研究　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：为了应对能源短缺和环境污染问题,在交通领域我国正大力发展新能源城市公交车。人们在公交车内度过的时间越来越多,车厢内的舒适性也成为人们日益关注的问题。热舒适性直接影响着司机和乘客的身心健康,同时影响着行车安全性和燃油经济性。所以,车厢内热舒适性研究越来越受到汽车公司的重视。现阶段,车厢内热舒适性的研究主要有试验和数值模拟两种方法。为缩短开发周期,降低成本,计算流体动力学(CFD,Computational Fluid Dynamics)方法在汽车设计开发过程中应用广泛。本文采用CFD方法研究车厢内气流组织分布和人员的热舒适性,计算结果为提高纯电动公交车的热舒适性、降低空调系统能耗和优化空调系统设计提供了依据。根据研究车型CDK6850CBEV的车身结构和物性参数,建立了稳态情况下的热负荷模型。运用MATLAB编写了热负荷计算程序,通过改变各种参数分析其对车厢热负荷的影响,提出降低整车热负荷的方法。通过ICEM建立了合理简化的公交车车厢内部三维模型。对网格无关性和湍流方程的选择进行了研究,确定选用Realizable k-ε模型。对车厢内速度场和温度场进行了测定实验,通过仿真结果和实验数据对比,吻合较好,验证了数值模拟的可靠性。用FLUNT软件对比计算了车厢内空载、满座和满座三种模型,对比计算了满座模型下十种不同送风参数工况。在结果分析时,应用Tecplot软件提取了大量典型截面的速度场和温度场分布图,以及某些特征点温度和速度沿车厢高度(Z轴)方向的数据。最后对结果进行对比,定性分析乘客数量和送风参数对车厢内气流组织和热舒适性的影响。调取FLUENT软件计算结果,并对其进行统计分析处理。选取车厢内几个典型截面,用不均匀系数法和空气扩散性能指数(ADPI)评价气流组织好坏;选取车厢内不同座位的人员,用当量温度(EQT)评价人体的热舒适性,用能量利用系数(投入能量利用系数)对公交车空调系统进行经济评价。最后,根据之前的分析结果,在保证送风参数(送风热量)不变的前提下,对公交车空调通风系统进行优化设计,主要是通过改变车玻璃材料、回风口布置和送回风方式。设计了多温区独立控制空调系统,使车厢内的热舒适性得到了很大的改善。
[Abstract]:In order to deal with the problem of energy shortage and environmental pollution, China is vigorously developing new energy city buses in the field of transportation. People spend more and more time in buses. Thermal comfort directly affects the physical and mental health of drivers and passengers as well as safety and fuel economy. More and more attention has been paid to the study of thermal comfort in cars. At present, the research of thermal comfort in cars mainly includes two methods: test and numerical simulation, in order to shorten the development period and reduce the cost. Computational fluid dynamics (CFD). Computational Fluid dynamics). The method is widely used in automobile design and development. In this paper, CFD method is used to study the distribution of airflow and the thermal comfort of persons. The results provide the basis for improving the thermal comfort of the pure electric bus, reducing the energy consumption of the air conditioning system and optimizing the design of the air conditioning system. According to the study of the body structure and physical parameters of the vehicle CDK6850CBEV. The model of heat load under steady state is established, and the calculation program of heat load is compiled by MATLAB. The influence of various parameters on the thermal load of carriage is analyzed by changing all kinds of parameters. This paper presents a method to reduce the heat load of the whole vehicle. Through ICEM, a reasonably simplified three-dimensional model of the bus compartment is established. The grid independence and the selection of turbulent equations are studied. The Realizable k- 蔚 model is chosen. The velocity field and temperature field in the car are measured. The simulation results are in good agreement with the experimental data. The reliability of numerical simulation is verified. The three models of no load, full seat and full seat are calculated by FLUNT software, and ten different conditions of air supply parameters under full seat model are calculated. Tecplot software is used to extract a large number of distribution maps of velocity field and temperature field of typical cross section, as well as the temperature and velocity data of some characteristic points along the Z axis of carriage height. Finally, the results are compared. This paper qualitatively analyzes the influence of passenger number and air supply parameters on airflow organization and thermal comfort in the carriage. The calculation results of FLUENT software are obtained, and the statistical analysis is carried out. Several typical sections of the carriage are selected. The non-uniformity coefficient method and the air diffusivity index (ADPI) were used to evaluate the airflow distribution. The thermal comfort of human body was evaluated by equivalent temperature EQT, and the economic evaluation of bus air-conditioning system was carried out with energy utilization coefficient (input energy utilization coefficient). According to the previous analysis results, under the premise that the air supply parameters (air supply heat) remain unchanged, the optimization design of the bus air conditioning ventilation system is carried out, mainly by changing the vehicle glass material. The air conditioning system with independent control in multi-temperature zone is designed, which improves the thermal comfort of the compartments greatly.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U469.72

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