More efficient electrochemical energy conversion through near-wall flow control

通过近壁流量控制实现更高效的电化学能量转换

基本信息

批准号：
239325001
负责人：
Professor Dr.-Ing. Christian Cierpka
金额：
--
依托单位：
Technische Thermodynamik
依托单位国家：
德国
项目类别：
Independent Junior Research Groups
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/239325001?language=en
关键词：
More efficient electrochemical energy conversion

项目摘要

The demand for energy is growing continuously due to the rising world population and the industrialization of emerging economies. An increasing part of this demand has to be produced using regenerative energy sources. Some of these sources, such as wind power and sunlight are not continuously available. Thus, the efficient energy storage is of great importance. Especially the electro chemical energy conversion in fuel cells or cells for electrolysis plays an important role. Since the reaction in these devices takes place at the electrodes surface, microfluidic solutions seem to be favourable. The surface can be largely increased by keeping the necessary volume small. The connection in series of plenty such microfluidic fuel cells can be used to establish the necessary power. The aim of the proposed project is to increase the efficiency of the electro chemical energy conversion by the application of near wall flow control and to understand the underlying physical phenomena in order to improve the design of future devices. Therefore measurements of the velocity field and scalar distributions of temperature, pH-value and pressure with high spatial and temporal resolution will be applied in single and multiphase micro flows. The proposed project focusses on the control of the near wall convection by the application of electromagnetic volume forces in multiphase systems and the flow control via passive secondary flows for single phase systems.One goal is the development of a microfluidic fuels cell in which the fuel and the oxidant flow next to each other without convective mixing. Therefore the expensive membrane of conventional fuel cell is not necessary. The efficiency of such a microfluidic fuel cell shall be enhanced using convection due to secondary flows which removes the depletion layer from the electrodes and refreshes the solution. Another goal is the investigation of the flow around single hydrogen bubbles produced on a macroscopic electrode mimicking a real electrolyser. Therefore highly resolved measurements of the velocity and the temperature will be performed with and without the application of Lorentz forces. Furthermore, a Marangoni convection was seen for the first time during water electrolysis on microelectrodes and further measurements on macroscopic electrodes on single hydrogen bubbles shall help to investigate if the origin of this phenomenon is related to temperature or concentration gradients.

由于世界人口不断上升和新兴经济体的工业化，对能源的需求正在不断增长。必须使用再生能源来产生这种需求的越来越多的部分。这些来源中的一些，例如风力和阳光，不连续可用。因此，有效的能量存储非常重要。尤其是燃料电池或电解细胞中的电能转化起着重要作用。由于这些设备中的反应发生在电极表面，因此微流体溶液似乎是有利的。通过保持必要的体积较小，可以大大增加表面。一系列大量微流体燃料电池的连接可用于建立必要的功率。拟议项目的目的是通过应用近壁流控制并了解基本的物理现象，以提高电能化学能量转化的效率，以改善未来设备的设计。因此，将在单个和多相微流中应用高空间和时间分辨率的温度，pH值和压力的标量分布的测量。提出的项目着重于通过在多相系统中应用电磁体积力和通过被动次级流的流量控制对近壁对流的控制。一个目标是开发微流体燃料燃料细胞，其中燃料和氧化剂流相互互相混合而无需对流混合。因此，无需使用常规燃料电池的昂贵膜。这种微流体燃料电池的效率应通过对流提高，这是由于次要流导致的对流，从而消除了电极的耗竭层并刷新溶液。另一个目标是研究模仿真实电解器的宏观电极上产生的单氢气泡周围的流动。因此，在有或不使用洛伦兹力的情况下，将执行速度和温度的高度分辨测量值。此外，在微电极上进行水电解期间，首次看到了马兰戈尼对流，并且在单个氢气气泡上的宏观电极上的进一步测量应有助于研究这种现象的起源是否与温度或浓度梯度有关。