地铁排热风流动与热湿耦合特性及其余热回收机理研究

It consumes a great quantity of power in subway running. An amount of waste heat is emitted meanwhile. As a result of the shortage in clear understanding toward the performance to waste heat in subway system, previous study on waste heat recovery from subway was limited. And the achievements have not been applied. Exhaust hot air is considered to be the most important object needing research for waste heat recovery from subway in this project. The operational process of exhaust hot air will be treated as a heat and moisture coupling problem during a channel flow with multi-source and variable flow rate. Mechanisms for fluid mechanics as well as heat and mass transfer will be simultaneously used in mathematical modeling exhaust hot air. A patented device named type heat exchanging muffler which is considered to be suitable for waste heat recovery from subway is proposed to solve the problem that the equipment occupies great area. Under the premise of giving a fully attention to the functions of both heat transfer and noise elimination, its mathematical model describing the flow process with heat transfer and noise elimination will be set up by integrating the mechanisms of fluid mechanics, heat transfer as well as acoustics. A test-bed will be built to exam the type heat exchanging muffler according to similarity theory. Field test will be taken on actually running exhaust hot air from subway in order to provide boundary conditions in mathematical models, supply input reference to test-bed, and serve as accordance of calculating and testing results. The process of waste heat recovery in subway will be analyzed by synthesizing the data resulted from simulation, model test and field test. Based on this, the performance of exhaust hot air from subway will be deeply understand, the mechanisms of the type heat exchanging muffler will be clarified, and the operating rules of the waste heat recovery system for exhaust hot air from subway will be grasped. All the work above will enrich the theory of the technology on waste heat recovery from subway.

地铁耗电量大，同时须排放大量余热。由于对地铁余热特性认识不足，致使既有地铁余热回收相关研究成果有限，且未能实际推广。本项目通过分析认为排热风应作为地铁余热回收的重点研究对象，将排热风运行过程归结为多源变流量流动热湿耦合问题，交叉利用流体力学和传热传质学理论建立其数学模型。为解决设备体积庞大等问题，提出适用于地铁排热风余热回收的专利设备片式换热消声器，在充分兼顾换热消声双重功能的前提下，融合流体力学、传热学及声学理论，建立其流动传热消声数学模型，依据相似原理搭建其模型试验台。对实际运行的地铁排热风系统开展现场测试，从而为数学模型提供边界条件，为模型试验提供输入参考，为计算、试验结果提供验证依据。整合模拟计算、模型试验及现场测试数据，分析地铁排热风余热回收过程，以求深刻认知地铁排热风特性，厘清片式换热消声器机理，把握地铁排热风余热回收系统运行规律，为余热回收技术在地铁中的发展应用增加理论储备。

地铁空间产生大量废热，须及时排除以保障设备正常运行及内部人员的舒适性。为对这部分废热加以利用，前人开发了多种废热回收设备和系统，但因自身局限性均未能真正得以推广使用。为克服该项技术的瓶颈，本研究分析了地铁废热特性，针对排热风道、车站隧道和车站设备用房三个区域开发了三套新型热回收系统或设备，给出了设计方法，并计算了使用这些新型热回收设备可能带来的热回收潜力。首先分析了地铁内部废热的来源及数量，得出地铁内部废热来源主要包括车辆启动制动产热、照明产热、车辆冷凝器散热、人员散热、其他设备散热等。由各项数量累计得隧道内的废热产量约为312kW，每个典型地铁车站设备用房的稳定废热产量约为210kW。继而对三种新型热回收系统的关键技术分别进行了研究。针对排热风道热回收设备体积大、布置困难的问题，开发了换热消声器，并对其性能进行了实验研究。结果表明，同等长度的换热消声器可获得比常规消声器更大的消声量，同时可获得18.42kW/m3的换热量。针对地铁隧道废热回收开发了模块化废热回收系统，该系统由模块化的蒸发器、冷凝器、压缩机、节流装置及水环路构成，可应用于新建或改建的地铁车站隧道。计算结果表明，仅在车站隧道及其附近的区间隧道内安装模块化蒸发器即可实现整条地铁隧道的废热回收。针对地铁车站的设备用房废热，分析了水环多联式热泵热回收系统应用的特殊性，建立了系统各部分的数学模型，在此基础上，计算了该新条件下系统的最佳环路水温，并对该技术应用于我国东北地区地铁车站设备用房废热回收以满足车站自身冬季供暖的废热回收潜力、系统能效比等进行了预估。结果表明，对于一个典型的地铁车站，在哈尔滨、长春、沈阳地区，该废热回收系统分别可获得534MW·h、491MW·h和396MW·h的废热回收量，系统能效比约为3.3，并且系统能效比几乎不随室外气候条件的变化而改变。该项研究的成果可作为地铁废热回收工程应用的理论参考。