透过多孔介质板热湿传递特性的实验研究

发布时间：2018-04-01 01:08

本文选题：质子交换膜燃料电池　切入点：增湿器　出处：《天津大学》2016年硕士论文

【摘要】：质子交换膜燃料电池(PEMFC)是一种高效、无污染的新型动力源,其具有能量密度高、启动速度快以及燃料来源广等优点。质子交换膜中的水含量会影响膜的质子传导能力以及机械强度,从而对燃料电池工作性能产生影响,因此对燃料电池进行水管理是必要的。电池内部的反应生成水不足以维持电池各种工作状态下的水平衡,所以采用外部增湿器对阴极进气进行增湿是合理有效的办法。本文主要研究一种以多孔碳板为核心技术的PEMFC外部增湿方式,通过实验对多孔碳板热湿传递特性的影响因素进行了研究。本文设计了测量透过多孔介质板的热湿传递特性实验系统,该系统由两个回路组成。本文进行了实验系统所需的加热加湿装置各参数的计算,以确保实验能够顺利进行。此外,还对整个实验系统的水平衡进行了计算,并且对误差结果进行了评估。本文针对流体流动参数对多孔介质板热湿传递特性的影响进行了实验研究,在使用相同的多孔介质板前提下,分别对气体流量、增湿气体温度以及相对湿度等因素对多孔介质板热湿传递特性的影响进行了实验。结果表明:气体流量的提高不利于被增湿气体温度和水分回收率的升高,但对水分传递量有促进作用;增湿气体相对湿度的提高对被增湿气体的温度和水分传递量提高有促进作用,但会导致水分回收率的降低;增湿气体温度的升高会明显提高被增湿气体的温度,且对水分传递量及水分回收率的提高均有促进作用,说明提高增湿气体进口温度可以提高增湿器的热湿传递性能。此外,本文还对多孔介质板的结构及物性参数对其热湿传递特性的影响进行了研究。选取了不同表面特性以及孔隙率的多孔介质板,在不同流体流动参数下分别进行了实验研究。结果表明:随着增湿气体进口相对湿度的提高,有肋面在高温侧及低温侧的热湿传递表现差异越发明显,有肋面在被增湿侧的传热效果较好,所以对多孔板被增湿侧表面肋化会促进其传热能力的提高;此外,孔隙率的提高会对多孔板的水分传递能力有明显地促进作用。
[Abstract]:Proton exchange membrane fuel cell (PEMFC) is a new type of power source with high efficiency and no pollution. It has the advantages of high energy density, high start-up speed and a wide range of fuel sources.The water content in the proton exchange membrane will affect the proton conductivity and mechanical strength of the membrane, which will affect the performance of the fuel cell, so it is necessary to manage the water of the fuel cell.The water generated by the reaction inside the battery is not enough to maintain the water balance of the battery under various working conditions, so it is reasonable and effective to use the external humidifier to humidify the cathode inlet air.In this paper, an external humidification mode of PEMFC with porous carbon plate as the core technology is studied, and the influencing factors of heat and moisture transfer characteristics of porous carbon plate are studied through experiments.In this paper, an experimental system for measuring the heat and moisture transfer characteristics through porous dielectric plates is designed. The system consists of two loops.In this paper, the parameters of the heating and humidifying device needed by the experimental system are calculated to ensure that the experiment can be carried out smoothly.In addition, the water balance of the whole experimental system is calculated, and the error results are evaluated.In this paper, the effects of fluid flow parameters on the heat and moisture transfer characteristics of porous media plates are studied experimentally.The effects of temperature and relative humidity of humidified gas on the heat and moisture transfer characteristics of porous media plates were studied.The results show that the increase of gas flow rate is not conducive to the increase of the temperature and water recovery rate of the humidified gas, but it can promote the moisture transfer.The increase of relative humidity of humidified gas can promote the increase of temperature and moisture transfer amount of humidified gas, but it will lead to the decrease of water recovery rate, and the temperature of humidified gas will obviously raise the temperature of humidified gas.It can also promote the increase of moisture transfer capacity and water recovery rate, which indicates that increasing the inlet temperature of humidifying gas can improve the heat and moisture transfer performance of humidifier.In addition, the influence of the structure and physical parameters of porous dielectric plate on the heat and moisture transfer characteristics is also studied.The porous media plates with different surface characteristics and porosity were studied experimentally under different fluid flow parameters.The results show that with the increase of the relative humidity of the inlet of the humidified gas, the difference of the heat and moisture transfer between the ribbed surface at the high temperature side and the low temperature side is more obvious, and the heat transfer effect of the ribbed surface on the humidified side is better.Therefore, the heat transfer ability of porous plate can be improved by the surface rib of the humidified side. In addition, the increase of porosity will obviously promote the water transfer ability of porous plate.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM911.4

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